No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Atmospheric CO 2 enrichment changes the wheat grain proteome
Abstract
Spring wheat (Triticum aestivum L. cv. Triso) was grown in a free-air CO2 enrichment (FACE) field experiment in order to gain information on CO2-induced effects on grain composition and quality at maturity. A proteome analysis was performed using two-dimensional gel electrophoresis (2-DE) and protein identification was done with mass spectrometry (MALDI-TOF MS). In elevated CO2 (526μl l−1), an increase of 13.5% in grain yield was observed relative to 375μl l−1 at a low level of significance (P=0.528). Total grain protein concentration was decreased by 3.5% at a high level of statistical significance. Most importantly, a number of statistically significant changes within the grain proteome were observed, as the levels of 32 proteins were affected by elevated CO2: 16 proteins were up-regulated and 16 were down-regulated. Our experiment demonstrates that high-CO2 can markedly affect the proteome of mature wheat grain. The potential role of the proteins, changed in response to CO2 enrichment, is discussed as some may affect grain quality. For the task of selecting cultivars resistant to CO2-induced quality loss, we propose to consider the proteins affected by elevated CO2 identified in this work here.
... These changes include the up-and downregulation of proteins with metabolic and stress-related functions and of storage globulins. 19,30,31 The S, Fe, and Zn acquisitions of the grains are complex processes involving root uptake and subsequent xylem translocation, remobilization from vegetative organs, and deposition in the grains. 32 The mechanism and environmental conditions leading to the reductions of grain S, Fe, and Zn concentrations by e[CO 2 ] are unclear. ...
... The decrease of crude protein concentration by e[CO 2 ] was associated with a decrease of gluten proteins, although the ALGL concentration was shown to be unaffected in previous FACE studies. 4,19,23,24,29,30 For instance, a strong decrease of HMW-GS, 19,30 which is particularly important for baking quality, 51 of all GLIA fractions (by 8−26%), 24 and all GLIA types (ω, α and γ) and GLUT subunits (HMW-GS and LMW-GS) (by 12−35%) 23 have been found. In the present study, however, apart from a slight decrease of total gluten concentration under all N levels and that of GLUT under Nad, no e[CO 2 ] effects on concentration and composition of gluten proteins were detected. ...
... The decrease of crude protein concentration by e[CO 2 ] was associated with a decrease of gluten proteins, although the ALGL concentration was shown to be unaffected in previous FACE studies. 4,19,23,24,29,30 For instance, a strong decrease of HMW-GS, 19,30 which is particularly important for baking quality, 51 of all GLIA fractions (by 8−26%), 24 and all GLIA types (ω, α and γ) and GLUT subunits (HMW-GS and LMW-GS) (by 12−35%) 23 have been found. In the present study, however, apart from a slight decrease of total gluten concentration under all N levels and that of GLUT under Nad, no e[CO 2 ] effects on concentration and composition of gluten proteins were detected. ...
Elevated atmospheric CO2 concentrations (e[CO2]) can decrease the grain quality of wheat. However, little information exists concerning interactions between e[CO2] and nitrogen fertilization on important grain quality traits. To investigate this, a two-year free air CO2 enrichment (FACE) experiment was conducted with two CO2 (393 and 600 ppm) and three (deficiency, adequate, and excess) nitrogen levels. Concentrations of flour proteins (albumins/globulins, gliadins, and glutenins) and key minerals (iron, zinc, and sulfur), and baking quality (loaf volume) were markedly increased by increasing nitrogen levels and varied between years. e[CO2] resulted in slightly decreased albumin/globulin and total gluten concentration under all nitrogen conditions, whereas loaf volume and mineral concentrations remained unaffected. Two-dimensional gel electrophoresis revealed strong effects of nitrogen supply and year on the grain proteome. Under adequate nitrogen, the grain proteome was affected by e[CO2] with 19 down-regulated and 17 up-regulated protein spots. The down-regulated proteins comprised globulins, but no gluten proteins. e[CO2] resulted in decreased crude protein concentration at maximum loaf volume. The present study contrasts with other FACE studies showing markedly stronger negative impacts of e[CO2] on chemical grain quality and reasons for that might be differences between genotypes, soil conditions or the extent of growth stimulation by e[CO2].
... 3−12 However, the improvement in the grain yield may occur at the expense of grain quality traits, such as nitrogen (N) and protein contents, mineral composition, or starch properties. 5,8,13 Durum wheat is the preferred raw material for the production of pasta worldwide. For pasta making, dough properties are crucial aspects of quality, and they are mostly determined by storage proteins of the wheat endosperm [here, "quality" refers to nutritional and end-use properties that can be influenced by the genetic background (wheat line) as well as culture management and environmental conditions]. ...
... In fact, numerous studies described in the literature have shown a general decrease in gluten protein fractions. 8,9,15,16 Along with a lowered protein concentration in grain, the amino acid composition has also been shown to be modified under elevated CO 2 . 17 The grain N content has been found to decrease as a result of a lower N pool available for remobilization from leaves. ...
... This shows that both the length of fatty acids used for esterification and the nature of membrane lipid headgroups (or the proportion of plastidial galactolipids) changed upon CO 2 enrichment. Some authors 8,31 found that the total lipid content remained unchanged in the high-CO 2 treatment, and others 32 found an increase in palmitate and a decrease in linoleate at high CO 2 . Our data suggest that the overall impact of elevated CO 2 on grain lipids depends upon the developmental stage considered and, therefore, that CO 2 influences the kinetics of lipid synthesis in grains. ...
... Wieser et al. (2008) [5] reported that HMW-GS fraction was more affected than LMW-GS fraction under eCO 2 . In wheat grain, HMW-GS represents about 12% of the total grain protein and plays an important role in determining the dough strength [32]. LMW-GS determined the dough extensibility and resistance and its level were also increased by eCO 2 in agreement with previous findings of Hogy et al. (2009b) [32]. ...
... In wheat grain, HMW-GS represents about 12% of the total grain protein and plays an important role in determining the dough strength [32]. LMW-GS determined the dough extensibility and resistance and its level were also increased by eCO 2 in agreement with previous findings of Hogy et al. (2009b) [32]. It has been reported that LMW-GS rapidly accumulates during early to mid grain filling while HMW-GS accumulates more rapidly during later phase of grain filling [33]. ...
... Homogeneous 10% polyacrylamide-Bis-Tris gel representing the effect of eCO 2 on two seed proteins determining the quality of seeds (a) Gluten and (b) Gliadin. been reported by Hogy et al.(2009b) [32]. While both glutens and their fractions were reduced in a comparable FACE study[5]. ...
Impact of elevated CO 2 (free air CO 2 enrichment) was studied on wheat (Triticum aestivum L. var Kundan) growth, yield and proteome. Elevated CO 2 significantly impacted both underground (+24%) and aboveground (+15%) biomass. Grain weight/plant and harvest index were increased by 35% and 11.4%, respectively under high CO 2. On the other hand, seed protein content was decreased by 19% under CO 2 enrichment while seed starch and soluble sugar contents were increased by 8% and 23%, respectively. Wheat leaf pro-teomics revealed that 50 proteins were showing differential expression. Twenty proteins were more abundant while 30 were less abundant. Thirty two proteins were identified by MALDI TOF TOF. More abundant proteins were related to defense, photosynthesis, energy metabolism etc. While less abundant proteins were related to glycolysis and gluconeogenesis. Wheat grain proteomics revealed that out of 49 differentially abundant proteins, 24 were more in abundance and 25 were less in abundance in wheat grains under eCO 2 condition. Thirty three proteins were identified and functionally characterized. They were found to be involved mainly in carbon metabolism, storage , defence and proteolysis. Gluten proteins are the major component of wheat storage proteins. Our results showed that both high and low molecular weight glutenins were more in eCO 2 wheat seeds while there was no change in gliadin evels. This might alter wheat dough strength. Concentration of grain Cr and As was increased at eCO 2 while that of Fe, Cu, Zn and Se were found to be decreased. Dynamics of carbon utilization and metabolic abilities of soil microbes under eCO 2 were significantly altered. Our study showed that altered wheat seed composition is cause for concern vis-à-vis nutrition and health and for industries which may have implications for agriculturally dominated country like India.
... However, those authors emphasise that differing results have been obtained among FACE experiments because of the interaction between CO 2 concentration and other environmental factors. CO 2 enrichment was shown to affect even the proteome profile of wheat grains under well-watered, temperate conditions (Högy et al. 2009b) and Mediterranean rainfed conditions (Fernando et al. 2015) in FACE facilities during a single growing season. ...
... Bologna seeds did show the accumulation of oxidatively modified polypeptides under e[CO 2 ]. The accumulation of APX and other defencerelated proteins in spring wheat grains under elevated CO 2 was also reported by Qiu et al. (2008) and Högy et al. (2009b). In plants, SOD and APX are two of the main ROS-scavenging enzymes, and constitute a highly efficient system for removing superoxide and hydrogen peroxide. ...
... Plants of various species exhibit altered antioxidant capacity and an increased oxidative stress under elevated CO 2 (Cheeseman 2006;Qiu et al. 2008;Naudts et al. 2014). This increased oxidative stress under elevated CO 2 might be due to increased canopy temperatures (Kimball et al. 1999;Högy et al. 2009b). Uncontrolled ROS production might have an impact on grain germination (Bykova et al. 2011). ...
The aim of this study was to investigate the impact of elevated concentration of carbon dioxide (CO2), as expected over coming decades, on yield and quality of winter bread wheat (Triticum aestivum L.). Plants (cv. Bologna) were grown by using the free-air CO2 enrichment (FACE) system at Fiorenzuola d'Arda under ambient (control) and elevated (570 ppm, e[CO2]) CO2 concentrations for two growing seasons. We addressed whether there would be a response of wheat grains to elevated CO2 concentration in terms of the contents of nitrogen (N), micro-and macronutrients, proteins and free amino acids. Under e[CO2], total wheat biomass and grain yield increased in both years of the study. Grain N percentage was reduced under e[CO2], but grain N yield (kg ha-1) was increased. Among macro-and micronutrients, a decrease in zinc concentration was observed. The proteome pattern was significantly different in grains grown at the two different CO2 levels, but the observed changes were highly dependent on interactions with prevailing environmental conditions. Finally, a negative trend was observed in the early germination rates of seeds from plants grown under e[CO2] compared with the controls. The results suggest that the expected increase in CO2 levels and their interactive effects with environmental variables may influence agronomic performance by increasing yield and negatively affecting quality.
... Shoot and grain N concentration is substantially decreased at e[CO 2 ] (Cotrufo et al., 1998;Kimball et al., 2002) and consequently, grain protein concentration is reduced (Hogy et al., 2009a). The grain proteome is also altered under e[CO 2 ] (Fernando et al., 2015;Hogy et al., 2009b;Panozzo et al., 2014). Therefore, understanding of grain protein and proteome responses to e[CO 2 ] will become increasingly important as CO 2 levels rise. ...
... It has been reported that the reduction of the gliadin to glutenin ratio under e[CO 2 ] leads to a deleterious effect on dough rheology characteristics (Wieser et al., 2008). Furthermore, metabolic proteins involved in diverse physiological processes have been changed under e[CO 2 ] (Hogy et al., 2009b). A recent study demonstrated a significant increase in metabolic proteins in wheat grain when plants are exposed to e[CO 2 ] . ...
... Responsive proteins under e[CO 2 ] can possibly serve as genetic markers to select useful quality traits and therefore, play an important role in future wheat breeding to adapt to climate stress (Hogy et al., 2009b). However, grain proteome analysis has been challenging due to the large dynamic range of proteins akin to that of the plasma proteome, but the principal advantage of using a proteomics approach is that, proteomic data allow estimating the post-translational changes in gene products that are not identified from transcriptome analysis. ...
The impact of rising carbon dioxide concentration ([CO2]) in the atmosphere on wheat grain protein concentration and proteome was investigated in this study. Wheat genotypes (H45, SB003, SB062 and Yitpi) were grown in the Australian Grains Free-Air CO2 Enrichment (AGFACE) facility, Horsham, Victoria, Australia under ambient [CO2] (a[CO2], ∼ 390 μmol mol⁻¹) and elevated [CO2] (e[CO2], ∼ 550 μmol mol⁻¹). Grain yield and grain protein concentration were measured. Global grain proteome comparison was carried out using stable isotope dimethyl labelling followed by liquid chromatography - mass spectrometry (LC-MS/MS). Grain yield was significantly increased at e[CO2], whereas protein concentration was significantly decreased and responses varied between genotypes. Proteome-wide analysis revealed that protein composition was also altered under e[CO2]. Grain protein concentration and composition of SB003 was very responsive to e[CO2]. Mainly storage proteins were decreased at e[CO2] and the responses varied between genotypes. These findings suggest that e[CO2] have a major impact grain protein quality and thus bread quality and human and animal nutrition. Further, these findings suggest that [CO2] insensitive cultivars can be identified for crop quality improvement under changing climate.
... Zhang et al. have studied the ALPs and its potential Fusarium head blight resistant functions [59], further illustrated their antifungal properties. Other research suggest that ALP type b are minor storage proteins which are important to protect endosperm starch reserves from degradation [60]. It is reported that, a putative ALP type b that comprises a cereal-type AAIs, as well as serpin-Z1C like defence proteins were increased by elevated CO 2 [60,61]. ...
... Other research suggest that ALP type b are minor storage proteins which are important to protect endosperm starch reserves from degradation [60]. It is reported that, a putative ALP type b that comprises a cereal-type AAIs, as well as serpin-Z1C like defence proteins were increased by elevated CO 2 [60,61]. Another novel study, indicated induction of one ALP and one chitinase in winter wheat (varieties. ...
Background:
Wheat grain avenin-like proteins (ALPs) belong to a recently discovered class of wheat grain storage protein. ALPs in wheat grains not only have beneficial effects on dough quality but also display antifungal activities, which is a novel observation for wheat storage proteins. Previous studies have shown that ALPs are likely present in the albumin/globulin fractions of total protein extract from wheat flour. However, the accumulation characteristics of these ALPs in the mature wheat grain remains unknown.
Results:
In the present study, a total of 13 ALPs homologs were isolated and characterized in the albumin/globulin fractions of the wheat protein extract. A combination of multiple techniques including RP-HPLC, SDS-PAGE, MALDI-TOF and peptide sequencing were used for accurate separation and identification of individual ALP homolog. The C-terminal TaALP-by-4AL/7DS, TaALP-by-4AL/7AS/7DS, TaALP-bx/4AL/7AS/7DS, TaALP-ay-7DS, TaALP-ay-4AL, TaALP-ax-4AL, TaALP-ax-7AS, and TaALP-ax-7DS, were separated as individual protein bands from wheat flour for the first time. These unique ALPs peptides were mapped to the latest wheat genome assembly in the IWGSC database. The characteristic defence related proteins present in albumin and globulin fractions, such as protein disulfide-isomerase (PDI), grain softness protein (GSP), alpha-amylase inhibitors (AAIs) and endogenous alpha-amylase/subtilisin inhibitor were also found to co-segregate with these identified ALPs, avenin-3 and α-gliadins. The molecular weight range and the electrophoresis segregation properties of ALPs were characterised in comparison with the proteins containing the tryp_alpha_amyl domain (PF00234) and the gliadin domain (PF13016), which play a role in plant immunity and grain quality. We examined the phylogenetic relationships of the AAIs, GSP, avenin-3, α-gliadins and ALPs, based on the alignment of their functional domains. MALDI-TOF profiling indicated the occurrence of certain post-translations modifications (PTMs) in some ALP subunits.
Conclusions:
We reported for the first time the complete profiling of ALPs present in the albumin/globulin fractions of wheat grain protein extracts. We concluded that majority of the ALPs homologs are expressed in wheat grains. We found clear evidence of PTMs in several ALPs peptides. The identification of both gliadin domain (PF13016) and Tryp_alpha_amyl domain (PF00234) in the mature forms of ALPs highlighted the multiple functional properties of ALPs in grain quality and disease resistance.
... In a number of countries, its influence on the formation of technological properties of flour and dough is studied [25,[43][44][45]. In some studies, besides properties, the changes in the grain proteome under the action of elevated CO 2 concentration have been assessed [45,46]. An increasing CO 2 in the atmosphere affects the gluten content and leads to a deterioration of baking properties, i.e. the bread volume of and flour strength decreases, while dough kneading takes more time. ...
... Under elevated CO 2 [50], changes had been observed in the ratio of the main protein fractions of gluten, the glutenins and gliadins. By contrast, elevated CO 2 concentrations do not reduce the expression of low molecular weight glutenins [45] or reduce their amount not as much as high molecular weight ones [46]. With low-molecular-weight glutenin such rheological properties are connected as dough extensibility and stability [51]. ...
The purpose of this interdisciplinary research is to analyze the available data on the domestic market of bakery products, assess the factors resulting in increase of the bread consumption, and opportunities of improvement of technological properties of flour and dough through the realization of the genetic potential of bread wheat varieties, taking into account environmental factors. In modern conditions, in the bakery products market of such negative tendencies are observed as decrease in volumes of bread production and deterioration of quality of the products. Among the various factors influencing the formation of these trends, one can point out the poor quality of flour, accompanied by deterioration in the rheological properties of the dough. In the practice, the correction of flour of inadequate quality is increasingly being made through the introduction of chemical improvers, which contributes to improving the technological process. At the same time there is a loss of traditional taste and a change in the consumer characteristics of bread, which leads to the refusal or reduction of consumption of bread by a part of the population of our country. This review summarizes data on the dynamics of average per capita consumption of bread and bakery products and the change in the ratio of these indicators to the consumption of meat products. An alternative approach to solving the problems of flour quality can be attributed to the possibilities of natural improvement of its initial characteristics through the realization of the genetic potential of bread wheat varieties, taking into account environmental factors that ultimately influence the formation of technological properties of flour and dough. In recent years, data have been accumulated that have made significant progress in understanding the complex interaction of various genetic systems and biochemical processes underlying the formation of grain properties that affect the quantity and quality of the flour. Integral components in this complex interaction are the environmental factors, under the influence of which the physiological and biochemical processes are modulated, and the mode of realization of genetic information is changing. The article summarizes the data on the influence of various environmental factors on the technological properties of flour and dough and describes the possibilities of modern IT-support of the selection process, facilitating the evaluation of quantitative characteristics and taking into account the relationship between genotype, phenotype and environmental conditions. Advances in the identification of genetic factors affecting the technological properties of flour and dough are discussed and sources of useful variants of these genes are considered. The importance of the use of winter bread wheat for increasing the share of production of high-quality nutritive grains is emphasized, as well as the results of the search for donors of useful genes among the old varieties of spring bread wheat. Among the latter, varieties with a high content of raw gluten and high elasticity of the dough have been identified. In conclusion, the ways of applying data on the influence of genetic and environmental factors on the formation of technological properties of flour and dough in a selection experiment are discussed, and the importance of obtaining varieties with genetically determined high strength of flour as a source of natural improver of weak flour is replaced in place of widely used chemical additives.
... В ряде стран изучается ее влияние на формирование технологических свойств муки и теста (25,(43)(44)(45). В отдельных исследованиях, кроме свойств, оценены изменения протеома зерна под действием повышенной концентрации СО 2 (45,46). Установлено, что в целом увеличение количества СО 2 в атмосфере существенно сказывается на содержании клейковины и приводит к ухудшению хлебопекарных свойств: снижается объем хлеба и сила муки, увеличивается продолжительность замеса. ...
... В условиях повышенного содержания углекислого газа (50) также наблюдали сдвиги в соотношении между основными белковыми фракциями клейковины -глютенинов и глиадинов. Напротив, повышенная концентрация CO 2 не снижает экспрессию низкомолекулярных глютенинов (45) или уменьшает их количество не столь сильно, как высокомолекулярных (46). Именно с низкомолекулярными глютенинами связаны такие реологические свойства, как растяжимость теста и его стабильность (51). ...
... Exposure at 700 ppm in the current study slightly decreased biomass production of the spike, stem, flag leaf and other leaves (although differences were not significant); however, there were increases in root biomass ( Fig. 1 and Table S1). Aranjuelo et al. (2011) in their FACE study with durum wheat contrasting [CO 2 ] conditions (700 versus 370 mmol mol À1 ), showed that elevated [CO 2 ] did not contribute to increased grain filling in wheat plants, and with other previous reports (Amthor, 2001;Högy et al., 2009;Uddling et al., 2008). Further, many studies indicated the variability of the responses to increased biomass at elevated [CO 2 ] in FACE and growth chambers. ...
... At elevated [CO 2 ] the autotrophic biomass in WW and mild WS was decreased by 36% and 19%, respectively, with leaves being the most affected organs. However, the root biomass increased 10% and 5% for WW and mild WS plants, respectively, and this is in agreement with previous reports (Amthor, 2001;Uddling et al., 2008;Högy et al., 2009;Aranjuelo et al., 2011). These data suggest that plants invest more C in roots than shoots at elevated [CO 2 ] and this effect is modulated by water availability, with a greater effect in WW plants. ...
Drought is the main constraint on wheat yield in Mediterranean conditions. The photosynthesis, chlorophyll fluorescence and plant growth parameters of durum wheat (Triticum turgidum, L. var. durum) were compared at three [CO2] (i.e., depleted 260 ppm, current 400 ppm and elevated 700 ppm) in plants subjected to two water regimes (i.e., well-watered WW, and mild water stress by drought or water deficit WS), during pre-anthesis, post-anthesis and the end of grain filling. We showed that [CO2] effects on plants are modulated by water availability. Plants at depleted [CO2] showed photosynthetic acclimation (i.e., up-regulation) and reduced plant biomass and Harvest Index, but depleted [CO2] combined with WS has a more negative impact on plants with decreases in C assimilation and biomass. Plants at elevated [CO2] had decreased plant growth and photosynthesis in response to a down-regulation mechanism resulting from a decrease in Rubisco and N content, but plants exposed to a combination of elevated [CO2] and WS were the most negatively affected (e.g., on plant biomass).
... In contrast to experimental warming, elevated [CO 2 ] can increase leaf photosynthesis and boost plant growth of C 3 species (Long et al., 2006), which can benefit more from CO 2 enrichment and meanwhile suffer less from climate warming under future global change (Kang et al., 2002;Bencze et al., 2014). Therefore, elevated temperature and [CO 2 ] may have combined effects on plant growth, water use efficiency, and crop grain yield (Taub et al., 2008;Högy et al., 2009;Nebauer et al., 2011) with modifying leaf photosynthesis (Bencze et al., 2014), dark respiration (Aranjuelo et al., 2011) and transpiration rates (Wei et al., 2018). Nevertheless, most of previous studies investigated plant growth and leaf photosynthesis in response to single environmental factor such as elevated [CO 2 ] or experimental warming (Yu et al., 2012a) and the mechanisms and processes of experimental warming modulating CO 2 fertilization effect on plants/crops are still unclear . ...
... In addition to carbohydrates and minerals, wheat grains also contain a substantial amount of storage proteins (gluten) which ultimately regulate Chaudhuri et al. (1986) Cotton, C 3 650 Field plot, OTC +60% above ground biomass; +63% seed cotton yield (lint plus seed) Kimball and Mauney (1993) Spring wheat, C 3 520 and 680 Pot culture, OTC Average +36% shoot biomass; +34% grain yield under elevated [CO 2 ] Fangmeier et al. (1996) Winter wheat, C 3 700 Polyethylene-covered tunnels +6%-31% biomass; +7%-44% seed dry weight Wheeler et al. (1996) Rice, C 3 586-645 Field plot, FACE Average +13% plant biomass; +11% grain yield Kim et al. (2003) Spring wheat, C 3 537-572 Field plot, FACE Average +11.8% above ground biomass; +10.4% grain yield Högy et al. (2009a) Maize, C 4 550 Field plot, FACE +24% biomass; +41% grain yield under limited water supply Manderscheid et al. (2014) Rice, C 3 490 Field plot, OTC Average +8% above ground biomass; -4% grain yield Satapathy et al. (2015) Soybean, C 3 550 Pot culture, OTC Average +46% shoot biomass; +40% seed yield Li et al. (2017) the dough-making properties of flour. Therefore, a reduction in the protein content and alterations of gluten components (glutenins and gliadins) under the elevated [CO 2 ] (Högy et al., 2009b) could destabilize the whole bakery industries around the world. ...
Impact of global climate change and atmospheric pollution have imposed a serious threat to food security in the 21st century and beyond. Elevated [CO2] and [O3] are able to induce physiological and biochemical changes in crops and thus affect their yield and quality. Growth chambers and free-air CO2 enrichment (FACE) are commonly used to assess agricultural outcomes under the projected future climate. Higher [CO2] mostly caused yield gain of C3 crops due to enhanced photosynthetic activities. However, temperature rise and precipitation variation have been projected to counteract the fertilization effect of CO2. Nevertheless, increased photosynthates accumulation under elevated [CO₂] might also degrade the grain quality. Therefore, suitable agro-technologies are required as adaptive measures. Increasing surface [O3] is another outcome of the changing climate. Anthropogenic activities release precursors (NOX and VOCs) which increased the surface [O₃] by 3-5 folds in the last 150 years. Uptake of the same through stomata results in oxidative stress in plants and significant loss of crop yields. The extent of damage differs among the species depending on the effectiveness of the antioxidants of each crop. Interestingly, elevated [CO₂] can ameliorate the damages caused by O₃ exposure and reduce the risk of yield loss upto 50%.
... Proteomics and metabolomics are considered as prominent strategies to study the responses of crop plants to different environmental conditions. The recently reported proteome and metabolomic studies on various crop plants, including wheat, basil and peppermint, majorly helped in understanding the molecular responses of these crops to elevated CO 2 (Hogy et al. 2009;Pandey et al. 2017;Jaouni et al. 2018;Soba et al. 2019). However, there are very limited studies to understand the legume seed responses to elevated CO 2 . ...
In the present study, we have analyzed the seed yield and seed quality of pigeonpea grown under elevated CO2. Pigeonpea was grown for its complete life cycle in open top chambers under elevated CO2 (600 µmol/mol) and atmospheric ambient CO2 (400 µmol/mol). The growth, biomass and seed yield were increased under elevated CO2 when compared to plants grown at ambient CO2 concentrations. The mature seeds were collected after 120 days for various biochemical analyses to determine their nutritional quality. The biochemical analyses indicated that elevated CO2 grown pigeonpea seeds did not show any significant decrease in nitrogen and protein contents but showed an increase in total carbohydrates. The metabolomics of seeds revealed changes in sugars, amino acids, organic acids and fatty acid levels under elevated CO2 growth. The seeds collected from elevated CO2 grown pigeonpea showed higher levels of essential amino acids inferring their better nutritional quality. The total proteome of pigeonpea seed was studied through label-free quantification and recorded an increase in several seed specific proteins including certain stress related proteins in elevated CO2 grown pigeonpea seeds. The proteome and metabolome data demonstrate better seed vigor in elevated CO2 grown pigeonpea.
... While the effect of introducing semi-dwarf varieties should also be considered, our study showed that increasing [CO 2 ] favored crop production. Previous experiments, carried out with wheat plants grown in environments where atmospheric [CO 2 ] was increased by 150-300 ppm, showed similar increases www.nature.com/scientificreports/ in grain yield values 5,24 . As has been widely described in these previous experiments, the higher yield records would be associated with the stimulation of photosynthetic rates. ...
The current study focuses on yield and nutritional quality changes of wheat grain over the last 166 years. It is based on wheat grain quality analyses carried out on samples collected between 1850 and 2016. Samples were obtained from the Broadbalk Continuous Wheat Experiment (UK) and from herbaria from 16 different countries around the world. Our study showed that, together with an increase in carbohydrate content, an impoverishment of mineral composition and protein content occurred. The imbalance in carbohydrate/protein content was specially marked after the 1960’s, coinciding with strong increases in ambient [CO2] and temperature and the introduction of progressively shorter straw varieties. The implications of altered crop physiology are discussed.
... A predicted increase of CO 2 concentration due to climate change is expected to increase yield in crops, particularly in C3 plants like wheat and rice, but to the detriment of quality (Leakey et al. 2009). Högy et al. (2009) reported changes in the wheat proteome due to increased CO 2 levels. Fernando et al. (2015) did a study on spring wheat with a maximum of 550 μm mol −1 CO 2 . ...
Gluten proteins account for 80% of wheat grain protein and are the largest contributor to wheat quality. Proteomics tools can be deployed in a programme designed to manipulate gluten proteins to improve quality and functional properties, to understand gluten structure and interrelationships between its components, and potentially to reduce allergies. The aim of this chapter is to review developments in the proteomics of gluten proteins, mainly from the last decade. It is clear that the technology used for gluten proteomics has developed significantly in this period, and the publication of the first completely sequenced wheat genome in 2014 has facilitated the application of these techniques in cereal research. Proteomics was shown to be useful for studying the effects of various biotic and abiotic stress conditions on gluten proteins during grain development. Proteomics will be increasingly important in investigating genotype by environment interaction in terms of baking quality characteristics. Great strides have also been made in the use of proteomics to identify gluten peptides with allergenic or toxic sequences. The integration of functional genomics, proteomics, bioinformatics, breeding and genetic resources is contributing to our understanding of the genetic and biochemical bases of quality traits in wheat. Technology is continually being developed and applied to elucidate interactions between biological molecules at all stages of the flow of genetic information in biological systems, and proteomics in combination with genomics will continue to play an important role in gluten protein research.
... Due to its high content of starch and gluten proteins, wheat is one of the most vital cereal crops worldwide (Hogy and Fangmeier 2008). The reported effects of CO 2 enrichment on protein and nitrogen content of wheat grains have mostly been negative (Blumenthal et al. 1996;Hakala 1998;Monje and Bugbee 1998;Högy et al. 2009b). Following CO 2 acclimation, an overall decline in shoot protein and nitrogen content has been documented in wheat (Bowes 1993;Moore et al. 1998;Makino and Mae 1999;Bloom et al. 2002), and it has been reported that the quality of wheat flour is likely to be impacted (Panozzo et al. 2014;Fernando et al. 2015). ...
... It is well known that a considerable number of proteins and enzymes, such as ZIP transporters, Nramp family proteins and Ca 2+ transporters, are involved in Cd uptake processes (Krämer et al., 2007). Within a certain range, elevated CO 2 concentrations can increase enzyme activity and protein synthesis (Högy et al., 2009), which results in higher metal uptake. Furthermore, elevated CO 2 could upregulate the expressions of heavy metal transport genes, and hence strengthen Cd tolerance and increase Cd accumulation (Wu et al., 2018). ...
... Thioredoxins regulate the cell redox environment by reducing protein disulphide bonds . Peroxidases, which catalyze the oxidation of phenolic compounds and protect cells from peroxide attack, have been recognized for their role in dehydration stress and pathogen defense (Högy et al. 2009). Among these proteins, three peroxidases (W5FA81, W5GIY3, W5AL94) peaked at 20 DPA and were sharply down-regulated at 30 DPA. ...
Using isobaric tags for relative and absolute quantification (iTRAQ) and associated analytic technologies, we have cataloged and compared 7 069 unique wheat proteins expressed during four substages of the filling stage. Among them, 859 are differentially expressed, showing at least a 2-fold difference in concentration across substages. Differentially expressed proteins (DEPs) includind high-molecular weight glutenin subunit (W5AIU1), low-molecular weight glutenin subunit (Q8W3V4), gliadin/avenin-like seed protein (D2KFG9), and avenin-like protein (W5DVL2), all of which have previously been identified as important for nutritional quality and bread-making properties, and all of which were found to increase at the latter stages of development. We have applied statistical techniques to group the proteins into hierarchical clusters, and have consulted databases to infer functional and other relationships among the identified proteins.
... Previous studies (Högy and Fangmeier 2008;Högy et al. 2010;Aranjuelo et al. 2013) conducted with wheat plants exposed to elevated [CO 2 ] show that crop yield will be increased. However, when [CO 2 ] effect is analysed in interaction with environmental stress factors, the elevated [CO 2 ] positive effect on plant production might be lower than expected or even insignificant (Högy et al. 2009;Aranjuelo et al. 2011Aranjuelo et al. , 2013Erice et al. 2014). ...
Predicted reduced precipitation, enhanced evaporative demand and increasing CO2 in the atmosphere will strongly influence wheat production. The association of wheat with arbuscular mycorrhizal fungi (AMF) improves growth under stressful conditions. Our objective was to test the influence of mycorrhizal inoculation on yield, and accumulation of macro- and micro-nutrients and gliadins in grains of durum wheat (Triticum durum Desf.) plants grown under different CO2 concentrations and water regimes. The main factors of the experimental design were mycorrhizal inoculation (inoculated or non-inoculated plants); atmospheric CO2 concentration (ambient, ACO2, or elevated, ECO2); and water regime (optimal or restricted water regime). At ACO2, the simultaneous application of AMF and water deficit decreased the number of seeds per spike without affecting the biomass of grains, and grains accumulated higher contents of copper, iron, manganese, zinc and gliadins. The opposite effect was observed with ECO2 where, regardless of mycorrhizal and water treatment factors, a general depletion of contents of micro- and macro-nutrients and gliadins was detected. Whereas mycorrhizal inoculation together with drought applied to plants cultivated at ACO2 improved wheat grain quality parameters, under ECO2, mycorrhization did not ameliorate grain quality parameters detected in plants that produced the largest grain dry matter values.
... The weather data recorded at experimental fields was used for calibration of the crops grown on them. Winter wheat, silage maize and winter rapeseed were grown on four fields in 2009 and three fields in 2010/2011 as part of normal crop rotations, grown over five, three and two seasons, respectively, to provide bi-weekly or monthly plant development (BBCH 1997) and leaf area index (LAI, 0+) measurements plus intermittent measurements on whole plant and generative biomass partitioned dry weight (DW, kg/ha) and nitrogen (N) concentration (% DW) (Högy et al. 2009;Ingwersen et al. 2011). Table 1 shows the number of plant measurements provided by field surveys for crop model calibration. ...
Agriculture is a largely technical endeavour involving complicated managerial decision-making that affects crop performance. Farm-level modelling integrates crop models with agent behaviour to account for farmer decision-making and complete the representation of agricultural systems. To replicate an important part of agriculture in Central Europe a crop model was calibrated for a unique region's predominant crops: winter wheat, winter and spring barley, silage maize and winter rapeseed. Their cultivation was then simulated over multiple decades at daily resolution to test validity and stability, while adding the dimension of agent behaviour in relation to environmental and economic conditions. After validation against regional statistics, simulated future weather scenarios were used to forecast crop management and performance under anticipated global change. Farm management and crop genetics were treated as adaptive variables in the milieu of shifting climatic conditions to allow projections of agriculture in the study region into the coming decades.
... Despite the expected increase in cereal production as a result of the projected increase in CO 2 (Manderscheid and Weigel 1995;Schütz and Fangmeier 2001;Högy et al. 2009a;Högy et al. 2010;Qiao et al. 2010), the interaction of CO 2 with environmental stress factors might decrease or eliminate the positive effect of elevated CO 2 on plant production (Högy et al. 2009b;Aranjuelo et al. 2011Aranjuelo et al. , 2013. According to Mitchell et al. (2001), elevated [CO 2 ] would have a minimal effect on plant growth under drought conditions because the rate of photosynthesis is already limited. ...
Despite its relevance, few studies to date have analysed the role of harvest index (HI) in the responsiveness of wheat (Triticum spp.) to elevated CO2 concentration ([CO2]) under limited water availability. The goal of the present work was to characterise the role of HI in the physiological responsiveness of durum wheat (Triticum durum Desf.) exposed to elevated [CO2] and terminal (i.e. during grain filling) water stress. For this purpose, the performance of wheat plants with high versus low HI (cvv. Sula and Blanqueta, respectively) was assessed under elevated [CO2] (700 mmol mol(-1) vs 400 mmol mol(-1) CO2) and terminal water stress (imposed after ear emergence) in CO2 greenhouses. Leaf carbohydrate build-up combined with limitations in CO2 diffusion (in droughted plants) limited the responsiveness to elevated [CO2] in both cultivars. Elevated [CO2] only increased wheat yield in fully watered Sula plants, where its larger HI prevented an elevated accumulation of total nonstructural carbohydrates. It is likely that the putative shortened grain filling period in plants exposed to water stress also limited the responsiveness of plants to elevated [CO2]. In summary, our study showed that even under optimal water availability conditions, only plants with a high HI responded to elevated [CO2] with increased plant growth, and that terminal drought constrained the responsiveness of wheat plants to elevated [CO2].
... Several molecular chaperones and APX were found to be up-regulated under higher CO 2 , whereas major photosynthetic proteins like RuBisCO and RuBisCO activase, different proteins of Calvin cycle were down-regulated. Hogy et al. (2009) have studied the effect of elevated CO 2 on the grain proteome of wheat (T. aestivum L. cv. ...
... The [CO 2 ]-derived stimulation of Sula was mainly due to an increase in grain DM. Although sink strength has been described to be a key factor conditioning plant responsiveness to elevated [CO 2 ] (Ziska et al., 2004;Alonso et al., 2008;Uddling et al., 2008;Högy et al., 2009Högy et al., , 2010Aranjuelo et al., 2011;Pérez et al., 2011), little attention has been given to HI as a target for research. The fact that Sula had a larger HI under both CO 2 levels reveals that this genotype has been subjected to more intense wheat breeding programmes seeking plants with proportionally larger ear grain DM (Ziska et al., 2004;Uddling et al., 2008;Foulkes et al., 2011;Reynolds et al., 2012). ...
The expansion of the world’s population requires the development of high production agriculture. For this purpose, it is essential to identify target points conditioning crop responsiveness to predicted [CO2]. The aim of this study was to determine the relevance of ear sink strength in leaf protein and metabolomic profiles and its implications in photosynthetic activity and yield of durum wheat plants exposed to elevated [CO2]. For this purpose, a genotype with high harvest index (HI) (Triticum durum var. Sula) and another with low HI (Triticum durum var. Blanqueta) were exposed to elevated [CO2] (700 µmol mol–1 versus 400 µmol mol–1 CO2) in CO2 greenhouses. The obtained data highlighted that elevated [CO2] only increased plant growth in the genotype with the largest HI; Sula. Gas exchange analyses revealed that although exposure to 700 µmol mol–1 depleted Rubisco content, Sula was capable of increasing the light-saturated rate of CO2 assimilation (Asat) whereas, in Blanqueta, the carbohydrate imbalance induced the down-regulation of Asat. The specific depletion of Rubisco in both genotypes under elevated [CO2], together with the enhancement of other proteins in the Calvin cycle, revealed that there was a redistribution of N from Rubisco towards RuBP regeneration. Moreover, the down-regulation of N, NO3
–, amino acid, and organic acid content, together with the depletion of proteins involved in amino acid synthesis that was detected in Blanqueta grown at 700 µmol mol–1 CO2, revealed that inhibition of N assimilation was involved in the carbohydrate imbalance and consequently with the down-regulation of photosynthesis and growth in these plants.
... The accumulation of carbohy - drates is in contrast to the improved water use efficiency , eventu - ally resulting in lower osmotic stress under elevated CO 2 levels . CO 2 - induced changes in the wheat grain proteome which revealed a higher level of the glycolytic enzyme glyceraldehyde - 3 - phos - phate dehydrogenase ( GAPDH ) and peroxidase ( Högy et al . , 2009c ...
Spring wheat (Triticum aestivum L.) was grown in a free-air carbon dioxide (CO2) enrichment (FACE) field experiment. Grain and biomass yield and its components were determined at maturity and the grain metabolome was analysed by gas chromatography-mass spectrometry (GC–MS). Elevated CO2 (537 versus 409 μl l−1) increased biomass production except for leaves. In total, levels of 16 grain metabolites were decreased and four were increased. CO2 enrichment resulted in significant decreases of amino acids such as o-acetyl-L-homoserine, leucine, arginine, L-homoserine and the group of ornithine, arginine and citrulline and negative trends for norleucine, L-aspartate, proline, L-cysteine and tyrosine. The amines D/L-diaminopimelate and alpha-ketoaminobutyrate and the polyamine putrescine were significantly decreased. In contrast, the polyamine spermidine tended to increase under elevated CO2. Among sugars and sugar derivatives, ribose-5-P was significantly increased, while gluconate-6-P was decreased. There were also negative CO2-induced effects on sugar alcohols: significant for glycerol-2-P (P = 0.008) and almost significant for myo-inositol-P (P = 0.066). In contrast, organic acids such as pyruvate and glucuronic acid were significantly increased. Overall, the N-rich metabolites especially were reduced. CO2 enrichment can markedly affect the physiology and metabolome of mature grains which may in turn lead to changes in nutritional status.
... As shown inTable 1, exposure to 700 lmol mol À1 CO 2 marginally decreased ear DM during the post-anthesis period (P¼0.093) and no effect was observed in total DM and ear DM/total DM ratio. This revealed that elevated [CO 2 ] did not contribute to increased grain filling, which is in agreement with previous reports (Amthor, 2001; Uddling et al., 2008; Hö gy et al., 2009). These results were corroborated in the supplementary harvest conducted at the grain maturity stage (see Supplementary Table S1 at JXB online). ...
Wheat plants (Triticum durum Desf., cv. Regallo) were grown in the field to study the effects of contrasting [CO2] conditions (700 versus 370 μmol mol−1) on growth, photosynthetic performance, and C management during the post-anthesis period. The aim was to test whether a restricted
capacity of sink organs to utilize photosynthates drives a loss of photosynthetic capacity in elevated CO2. The ambient 13C/12C isotopic composition (δ13C) of air CO2 was changed from –10.2‰ in ambient [CO2] to –23.6‰ under elevated [CO2] between the 7th and the 14th days after anthesis in order to study C assimilation and partitioning between leaves and ears.
Elevated [CO2] had no significant effect on biomass production and grain filling, and caused an accumulation of C compounds in leaves.
This was accompanied by up-regulation of phosphoglycerate mutase and ATP synthase protein content, together with down-regulation
of adenosine diphosphate glucose pyrophosphatase protein. Growth in elevated [CO2] negatively affected Rubisco and Rubisco activase protein content and induced photosynthetic down-regulation. CO2 enrichment caused a specific decrease in Rubisco content, together with decreases in the amino acid and total N content of
leaves. The C labelling revealed that in flag leaves, part of the C fixed during grain filling was stored as starch and structural
C compounds whereas the rest of the labelled C (mainly in the form of soluble sugars) was completely respired 48 h after the
end of labelling. Although labelled C was not detected in the δ13C of ear total organic matter and respired CO2, soluble sugar δ13C revealed that a small amount of labelled C reached the ear. The 12CO2 labelling suggests that during the beginning of post-anthesis the ear did not contribute towards overcoming flag leaf carbohydrate
accumulation, and this had a consequent effect on protein expression and photosynthetic acclimation.
Previous studies indicated the grain yield and compositions of wheat (Triticum aestivum L.) were affected by long-term elevated atmospheric CO2 concentration conditions. However, the roles of protein expression in wheat grain quality changes under multigenerational elevated atmospheric CO2 concentration are still rarely known. This study explored that the changes of grain quality in wheat offspring induced by multigenerational elevated atmospheric CO2 concentration exposure and analyzed the roles of the differently expressed proteins using 4D proteomics in regulating the wheat grain quality. The changes of grain protein accumulation, gluten index and dough development time indicated that the nutritional and end-use quality of wheat grains were directly affected by elevated atmospheric CO2 concentration. This was mainly due to the changed expressions of α-amylase inhibitors, glutamine synthetase, glutamate dehydrogenase, formamidase and β-glucosidase, which regulated the starch accumulation and nitrogen metabolism in grains. This study elucidates the mechanisms underlying the effects of long-term elevated atmospheric CO2 concentration on wheat grain quality.
The user has requested enhancement of the downloaded file.
Understanding the key processes and potential mechanisms of crops in response to elevated atmospheric CO2 concentration and drought may further shed lights on the impacts of climate change on the global agriculture ecosystems. This study examined the effects of elevated atmospheric CO2 concentration on the growth of winter wheat under different soil water conditions (full irrigation, mild water stress, moderate water stress, and severe water stress) with growth chambers where the CO2 concentration was controlled at 400 and 800 µmol mol⁻¹, respectively. We found a very strong CO2 fertilization effect on the growth of winter wheat under full irrigation condition, whereas this CO2 fertilization effect declined and eventually vanished with soil water stress, as evidenced by the decreased plant biomass and leaf photosynthesis of winter wheat independent of CO2 concentration. This adverse impact of water stress on the CO2 fertilization effect for plant growth may attribute to the changes in morphological characteristics of individual stoma and spatial distribution pattern of stomata as well as the non-structural carbohydrates of winter wheat. These results suggested that water stress may lower the CO2 fertilization effect on plant growth through altering stomatal traits, leaf photochemical processes, and biochemical compositions of winter wheat. Therefore, many current climate models based on earlier “double-CO2” experiment may overestimate the CO2 fertilization effect on crops, and meanwhile underestimate the impacts of climate change on global agriculture production when the elevated atmospheric CO2 concentration confounded with drought stress under future climate change.
Global climate changes involve elevated temperature and CO2 concentration, imposing significant impact on plant growth of various plant species. Elevated temperature exacerbates heat damages, but elevated CO2 has positive effects on promoting plant growth and heat tolerance. The objective of this study was to identify metabolic pathways affected by elevated CO2 conferring the improvement of heat tolerance in a C4 perennial grass species, bermudagrass (Cynodon dactylon Pers.). Plants were planted under either ambient CO2 concentration (400 μmol⋅mol-1) or elevated CO2 concentration (800 μmol⋅mol-1) and subjected to ambient temperature (30/25°C, day/night) or heat stress (45/40°C, day/night). Elevated CO2 concentration suppressed heat-induced damages and improved heat tolerance in bermudagrass. The enhanced heat tolerance under elevated CO2 was attributed to some important metabolic pathways during which proteins and metabolites were up-regulated, including light reaction (ATP synthase subunit and photosystem I reaction center subunit) and carbon fixation [(glyceraldehyde-3-phosphate dehydrogenase, GAPDH), fructose-bisphosphate aldolase, phosphoglycerate kinase, sedoheptulose-1,7-bisphosphatase and sugars) of photosynthesis, glycolysis (GAPDH, glucose, fructose, and galactose) and TCA cycle (pyruvic acid, malic acid and malate dehydrogenase) of respiration, amino acid metabolism (aspartic acid, methionine, threonine, isoleucine, lysine, valine, alanine, and isoleucine) as well as the GABA shunt (GABA, glutamic acid, alanine, proline and 5-oxoproline). The up-regulation of those metabolic processes by elevated CO2 could at least partially contribute to the improvement of heat tolerance in perennial grass species.
The success or otherwise of novel grain-based products is ultimately determined by the consumers because they ‘vote’ with their purchasing power. Trends are also determined by the scientist (who develops notional feasibilities) and the technologist (who dwells on realities in pursuing innovations). The breeder has a key role to play by introducing genotypes with novel quality attributes, which can be exploited further down the grain chain. New technologies are being introduced to assist the grain grower in providing quality grain, even though in a changing climate. New technologies will facilitate quality-based segregation of grain at harvest, helping to maximise returns to growers and to provide more uniform quality for processors. The nutritional value of grain-based foods will continue to feature as a major factor in the processing and retailing of foods based on grains.
A simulated climate warming experiment was conducted to evaluate the combined effects of elevated temperature and CO2 concentration on the bioaccumulation, translocation and subcellular distributions of Cd and Zn in wheat seedlings (Triticum aestivum L. cv. Xihan 1.) at Dingxi, Gansu Province, China. The objective of this study was to find evidence that global climate change is affecting the bioaccumulation of Cd and Zn in T. aestivum L. cv. Xihan 1. The results showed that compared to control A, elevated temperature and CO2 increased Cd bioaccumulation in the shoots by approximately 1.4–2.5 times, and increased that in the roots by approximately 1.2–1.5 times, but decreased Zn levels in wheat shoots by approximately 1.4–2.0 times, while decreased that in the roots by approximately 1.6–1.9 times. Moreover, temperature and CO2 concentration increase also led to increased Cd concentration, and decreased Zn concentration in subcellular compartments of wheat seedlings. The largest Cd concentration increase (174.4%) was observed in the cell wall and debris fractions of shoots after they were subjected to the highest CO2 and temperature treatment (TC3). The largest Zn concentration decrease (53.1%) was observed in the soluble (F3) fractions of shoots after they were subjected to the medium CO2 and temperature treatment (TC2). The temperature and CO2 increase had no significant effect on the proportional distribution of Cd and Zn in the subcellular fractions. In addition, the root-to-shoot translocation of Cd significantly increased with the increasing temperature and CO2 concentration. However, the Zn distributions only fluctuated within a small range.
Wheat is unique as a source of the gluten proteins that alone have the dough-forming properties needed to make the variety of foods that rely on the rheology of dough, namely, leavened breads, pasta, noodles, flat/pocket breads, steamed breads, biscuits, cakes, pastries and various food ingredients. Therefore wheat, an essential part of the diet of most of the world's population, is prominent in world trade. Its quality traits are the most critical of all the grains. The glutenin polypeptides (subunits) make a substantial contribution to the wheat quality and their composition is used extensively as a selection tool in breeding and in quality-based segregation of grain.
In this manuscript, an effort has been made to analyze the 19 research studies with 82 experiments being conducted in 9 countries of the world. Selected studies based on growth, yield and yield components of Wheat (Tritium aestivum L.) crop under various CO2 levels. Only the recently published real research studies (excluding models and mathematical tools based research) were considered in the study. More than 90 percent of research findings proved that elevated CO2 have positive impact on growth, yield and its components. Majority of the observations confirm that the elevated CO2 improved the yield of crop due to significant increase in growth and growth parameters like leaf area index, plant height, leaf area duration etc. No doubt elevated CO2 have positive impact on various growth and yield parameters but when we consider the impact of climate change (elevated temperature, drought, and increasing concentration of anthropogenic gases like CO, CH4 etc.) the response of CO2 will become negative. Even though elevated levels of CO2 has potential to compensate the impact of other changes in climate and may create a path in future to meet the demand of burgeoning world population.
Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies, causing a loss of 63 million life-years annually. Most of these people depend on C3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO2 concentration predicted for the middle of this century. C3 crops other than legumes also have lower concentrations of protein, whereas C4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO2 concentration could partly address these new challenges to global health.
Spring wheat (Triticum aestivum L. cv. Triso) was grown in a free-air carbon dioxide (CO2) enrichment (FACE) system at Stuttgart–Hohenheim (Germany) in 2008 to examine effects on crop yield and grain quality. Elevated CO2 had no significant impacts on aboveground biomass and grain yield components except for an increase in thousand grain weight by 5.4% with size distribution shifted towards larger grains. Total grain protein concentration decreased by 7.9% under CO2 enrichment, and protein composition was altered. Total gliadins and their single types (ω5-gliadins, ω1,2-gliadins, α-gliadins, and γ-gliadins) were reduced, while albumins/globulins, total glutenins and their subunits were not influenced. The gluten proteins (gliadins plus glutenins) were lowered by 11.3% in the high-CO2 treatment, whereas proportions of gluten protein types were slightly affected as only ω1,2-gliadins decreased. Accordingly, all proteinogenic amino acids were decreased by 4.2 to 7.9% in concentrations per unit flour mass, although partly below the level of statistical significance. In contrast, the composition of amino acids on a per protein basis remained unaffected except for a decline in serine. Among the minerals, the concentrations of calcium, magnesium, iron and cobalt decreased, while an increase was observed for boron. The concentrations of total non-structural carbohydrates and starch decreased, whereas fructose, raffinose and fructan increased. Total lipid concentration remained unaffected by the CO2 enrichment, whereas the grain carbon/nitrogen relation was increased by 8.5%. Implications may occur for consumer nutrition and health, and for industrial processing, thus breeding of new wheat cultivars that exploit CO2 fertilisation and maintain grain quality properties is regarded as one potential option to assure the supply chain for the future.
In this study, we developed and analyzed a new model for the simulation of photosynthetic active nitrogen (NP) turnover dynamics in crops and assessed its impact on the acclimation of canopy photosynthesis to atmospheric CO2 enrichment. Typical canopy models assume a vertical exponential decline of light interception following the Beer–Lambert law and vertical distributions of leaf NP contents directly proportional to the light distribution. This assumption is often inconsistent with experimental observations. We therefore modified and extended the photosynthesis model of the GECROS crop model to consider the trade-off that occurs between the use of degraded NP for plant growth and the synthesis of new NP. This model extension thus enabled the examination of the CO2-induced down-regulation of photosynthesis hypothesis using a crop model. The simulation results of the original and modified GECROS model were compared and evaluated based upon measurements of field-grown spring wheat. The modified GECROS model better simulated the dynamics of crop growth under varying atmospheric CO2 concentrations. Furthermore, the application of different temperature functions to NP degradation strongly influenced the simulation results, revealing the necessity for improving the understanding of the temperature dependence of NP turnover for different crop species and varieties. In conclusion, the redistribution of nitrogen within the plant and its alternative use either for growth or the optimization of the photosynthetic apparatus is an important mechanism for crop growth acclimation to regionally changing climatic conditions and in particular, atmospheric CO2 enrichment.
Trend of atmospheric carbon dioxide concentration [CO2] in last fifty years, known as 'Keeling curve', and monitoring of CO2 in Mauna Loa Observatory of Hawaii is described in the paper. Enhanced level of CO2 affects plants, including wheat, which is one of the most important crop plant species. Some changes caused by this factor are positive, particularly faster growth, development and better photosynthesis of plants. On the other hand, elevated [CO2] affected lower yield quality. Some results of own experiments on the wheat plants are presented.
The increasing concentration of atmospheric CO2 and the nutritional quality of human diets are the two important issues we are facing. At present, the atmospheric CO2 concentration is about 380 micromol mol(-1), and to be reached 550 micromol mol(-1) by 2050. A great deal of researches indicated that the quality of agricultural products is not only determined by inherited genes, but also affected by the crop growth environmental conditions. This paper summarized the common methods adopted at home and abroad for studying the effects of CO2 enrichment on the quality of agricultural products, and reviewed the research advances in evaluating the effects of elevated CO2 on the quality of rice, wheat, soybean, and vegetables. Many experimental results showed that elevated CO2 concentration causes a decrease of protein content in the grains of staple food crops and an overall decreasing trend of trace elements contents in the crops, but improves the quality of vegetable products to some extent. Some issues and future directions regarding the effects of elevated CO2 concentration on the quality of agricultural products were also discussed, based on the present status of related researches.
In an attempt to further elucidate the impact of elevated levels of CO2 on grain protein composition and quality a proteome analysis was performed. Wheat (Triticum aestivum L. cv. H45), was grown in the Australian Grains Free-Air Carbon dioxide Enrichment (AGFACE) facility under current ambient [CO2] (384 µmol mol-1) and elevated [CO2] (550 µmol mol-1) in 2009 growing season. Crops were sampled at harvest maturity and carbon (C), nitrogen (N) and sulphur (S) concentrations of leaves, sheaths and spikes were analysed. Total protein content in whole-grain was determined by near infrared reflectance spectroscopy. Comparative proteomics analysis was performed using 2-D DIGE and protein identification was performed with matrix assisted laser desorption ionisation mass spectrometry (MALDI TOF/TOF MS) Analyser. Total grain protein concentration was significantly declined by (8.7%) and grain yield was increased by (38.2%) at elevated [CO2]. Total N uptake was much greater at elevated CO2, although N allocation per grain was lower at elevated CO2.
Grain proteome was significantly changed under elevated [CO2], seven proteins were down regulated by a factor (1.5 to <2) while three proteins were up regulated (1.5 to <2). Four down regulated proteins were identified as glutenin high molecular weight sub units (HMW-glutenin) and 1-Cys peroxiredoxin. Two up regulated proteins were identified as serpin Z1C. Most of the flour rheological properties were affected by elevated [CO2] and amount of water received by crops including a significant reduction in bread volume. Changes of flour rheological proerties were closely link with the compositional changes of grain proteome. These findings indicate that reduction of HMW-glutenin one of major strage protein in wheat grain, is mainly responsible for the total reduction of grain protein concentration at higher atmospheric [CO2].
Proteome analysis was conducted on the grain of 2 closely related soft biscuit-making wheats (Bowie and Rosella cultivars) differing in processing quality. Comparisons between these wheat cultivars were carried out on total wholemeal proteins, extracts with enriched starch granule proteins, and extracts enriched with gliadin storage proteins, with the intention of characterising, identifying, and cataloguing cultivar-specific proteins that could be used for segregation purposes. Initially, 2-dimensional gel electrophoresis was carried out on total wholemeal proteins using a broad range pH 3-10 immobilised pH gradient for the first dimension. Further screening was carried out using a combination of mid to narrow range immobilised pH gradients, including pH 4-7, 5.5-6.7, 5-8, 6-9, and 6-11. Best cultivar-specific protein fractionation was provided by the pH 5-8 range. Altogether, 4 unique cultivar-specific protein spots were excised from the pH 5-8 gels and identified by means of peptide mass fingerprinting, tandem mass spectrometry, or N-terminal sequencing. Starch granule protein extracts were prepared and fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A western blot was performed and probed with an anti-puroindoline-a antibody. Further to this, extracts enriched in gliadin storage proteins were isolated using 70% ethanol and analysed by 2-dimensional gel electrophoresis. The resulting gliadin protein maps showed 18 unique cultivar-specific gliadins. They were excised from the pH 6-9 gels and submitted for N-terminal amino acid sequencing. Overall, this study identified 23 proteins that could be used to distinguish between these closely related cultivars and may provide information on the molecular basis for the differences in processing exhibited by these wheats. The findings reported also contribute to a longer term objective of developing a broad and comprehensive knowledge base of commercial wheats, in regard to protein composition and their inherent processing qualities.
Summary • The likely consequences of future high levels of atmospheric CO2 concentration on wheat (Triticum aestivum L.) grain nutritional and baking quality were determined. • Two free-air CO2 enrichment (FACE; 550 mmol mol−1) experiments were conducted at ample (Wet) and limiting (Dry) levels of irrigation, and a further two experiments at ample (High-N) and limiting (Low-N) nitrogen concentrations. Harvested grain samples were subjected to a battery of nutritional and bread-making quality tests. • The Dry treatment improved grain quality slightly (protein +2%; bread loaf volume +3%). By contrast, Low-N decreased quality drastically (protein −36%; loaf volume −26%). At ample water and N, FACE decreased quality slightly (protein −5%; loaf volume −2%) in the irrigation experiments and there was no change in the nitrogen experiments. At Low-N, FACE tended to make the deleterious effects of Low-N worse (protein −33% and −39%, at ambient CO2 and FACE, respectively; loaf volume −22% and −29% at ambient CO2 and FACE, respectively). • The data suggest that future elevated CO2 concentrations will exacerbate the deleterious effects of low soil nitrogen on grain quality, but with ample nitrogen fertilizer, the effects will be minor.
Atmospheric CO(2) concentration ([CO(2)]) is now higher than it was at any time in the past 26 million years and is expected to nearly double during this century. Terrestrial plants with the C(3) photosynthetic pathway respond in the short term to increased [CO(2)] via increased net photosynthesis and decreased transpiration. In the longer term this increase is often offset by downregulation of photosynthetic capacity. But much of what is currently known about plant responses to elevated [CO(2)] comes from enclosure studies, where the responses of plants may be modified by size constraints and the limited life-cycle stages that are examined. Free-Air CO(2) Enrichment (FACE) was developed as a means to grow plants in the field at controlled elevation of CO(2) under fully open-air field conditions. The findings of FACE experiments are quantitatively summarized via meta-analytic statistics and compared to findings from chamber studies. Although trends agree with parallel summaries of enclosure studies, important quantitative differences emerge that have important implications both for predicting the future terrestrial biosphere and understanding how crops may need to be adapted to the changed and changing atmosphere.
Storage proteins account for about 50% of the total protein in mature cereal grains and have important impacts on their nutritional
quality for humans and livestock and on their functional properties in food processing. Current knowledge of the structures
and properties of the prolamin and globulin storage proteins of cereals and their mechanisms of synthesis, trafficking and
deposition in the developing grain is briefly reviewed here. The role of the gluten proteins of wheat in determining the quality
of the grain for breadmaking and how their amount and composition can be manipulated leading to changes in dough mixing properties
is also discussed.
To identify future impacts on biomass production and yield quality of important C3 crops, spring wheat was grown in association with 13 weed species in a Mini-FACE (free-air carbon dioxide (CO2) enrichment) system under ambient (375 μl l-1) and elevated (526 μl l-1) CO2 concentrations. Wheat productivity was assessed at maturity and grain yield was subjected to various chemical analyses and baking quality tests.
CO2 enrichment acted as carbon ‘fertiliser’ and increased the aboveground biomass production of wheat by 18.8% as there was a trend towards higher stem biomass. Although not statistically significant, wheat grain yield was increased by 13.4% due to a significant establishment of more grains per unit ground area. At the same time, thousand grain weight was non-significantly shifted towards smaller grain size classes, which may result in negative consequences for the crop market value. As a result of the CO2- induced physiological and biochemical modifications, concentration of total grain protein was significantly decreased by 3.5%, reducing the wheat grain quality with potentially far-reaching impacts on the nutritional value and use for processing industry. Although often not significant, the concentrations of amino acids per unit of flour were decreased by 0.2 to 8.3% due to elevated CO2 thereby affecting the composition of proteinogenic amino acids.
Furthermore, gluten proteins tended to decline. Within the significant decreased gliadins, α- and ω5-gliadins were significantly reduced under CO2 enrichment; there was also a negative trend for ω1,2- and γ-gliadins. Changes in certain essential minerals were found as well, although not statistically significant. Concentrations of sodium, calcium, phosphorus and sulphur were slightly lowered and those of potassium and magnesium were slightly increased due to CO2 enrichment. The micro-element molybdenum was increased, while concentrations of iron, zinc, copper, manganese and aluminium were decreased. With regard to rheological and baking parameters defining the cereal quality for industrial processing, the resistance of the dough was significantly reduced by about 30%, while the extensibility was non-significantly increased by 17.1% under CO2 enrichment. Moreover, the bread volume was decreased non-significantly by about 9%. Elevated CO2 is obviously affecting grain characteristics important for consumer nutrition and health, industrial processing and marketing. Experimental evidence for these changes is still poor but deserves further attention.
In order to determine the likely effects of the increasing atmospheric CO2 concentration on future evapotranspiration, ET, plots of field-grown wheat were exposed to concentrations of 550 mumol/mol CO2 (or 200 mumol/mol above current ambient levels of about 360 mumol/mol) using a free-air CO2 enrichment (FACE) facility. Data were collected for four growing seasons at ample water and fertilizer (high N) and for two seasons when soil nitrogen was limited (low N). Measurements were made of net radiation, Rn; soil heat flux; air and soil temperatures; canopy temperature, Ts; and wind speed. Sensible heat flux was calculated from the wind and temperature measurements. ET, that is, latent heat flux, was determined as a residual in the energy balance. The FACE treatment increased daytime Ts about 0.6° and 1.1°C at high and low N, respectively. Daily total Rn was reduced by 1.3% at both levels of N. Daily ET was consistently lower in the FACE plots, by about 6.7% and 19.5% for high and low N, respectively.
Seed proteins of 28 Australian bread wheat cultivars were analysed by gel electrophoresis to indicate variations in the composition of their gliadins and glutenin polypeptides (both low- and high-molecular-weight). Composition was indicated according to allelic blocks of genes for each protein class and for each chromosome involved. Relationships were studied between gluten-protein alleles, pedigrees and dough properties (in the Extensograph). Overall, gliadins and low-molecular-weight (LMW) subunits of glutenin controlled by group 1 chromosomes showed closest relationships with each other. LMW subunits were most highly correlated with dough resistance and extensibility. Gliadins controlled by chromosomes 6A and 6D also had highly significant relationships to dough resistance and extensibility, respectively. Among high-molecular-weight subunits of glutenin, however, only those controlled by chromosome 1B showed a significant relationship with resistance to dough extension.
The importance of glutenin in bread-making quality has led to a substantial research effort. Studies on glutenin can be grouped into four categories: studies that determine the statistical relationships between the quantity of fractions and quality, studies of reconstitution and fortification, breeding and genetic modification, and those that assess structure–function relationships during processing. Statistical relationships between glutenin, glutenin fractions and glutenin polypeptides and quality have been established. The SDS or acetic acid unextractable glutenin correlated strongly with quality parameters. For highMrglutenin subunits the relationships with quality are less strong. In some studies it was demonstrated that the presence of some highMrglutenin subunits is correlated with the quantity of unextractable glutenin. Therefore, subunits are probably indirectly linked with bread-making qualityviathe quantity of unextractable glutenin. Recombination and fortification studies are hampered by changes in functionality of proteins after their separation. Recently, small scale tests have been developed in which small amounts of glutenin fractions can be studied. Controlled breeding studies have demonstrated the importance of highMrglutenin subunits 5+10 and, to a lesser extent, 1 or 2* for quality. In most of these studies the quantity of unextractable glutenin is not reported. This hampers adequate conclusions on cause–effect relationships. During dough processing large changes occur in the extractability of glutenin. The significance of these changes for dough properties and bread quality still requires investigation.
The present investigation was undertaken in order to study the influence of ozone, carbon dioxide and water availability on the relationship between grain protein and grain yield in wheat (Triticum aestivum L.). Results were combined from spring wheat, field grown in 16 different open-top chamber experiments, from four different countries. Protein concentration of the grain was negatively (linear) associated with grain yield. This relationship was symmetrical for yield reductions and yield stimulations, despite the fact that the major cause for increases in yield (elevated carbon dioxide concentrations) was different from that causing crop loss (elevated ozone concentrations). The relationship between off-take (the amount of protein taken away from the farmland per unit area) of grain protein and grain yield was clear and highly consistent, but not linear. Yield loss in relation to the reference used (open-top chamber with non-filtered air) was associated with a larger negative change in protein off-take than the positive change in protein off-take corresponding to a yield increase of the same size. The water treatments used in some of the experiments influenced yield and protein content to a very limited extent. It is concluded from the present study that the change of the grain protein from factors such as ozone and carbon dioxide can be explained largely by a simple relationship between grain protein and grain yield at a certain level of nitrogen availability to the plants.
Resource allocation in high CO2 was studied with respect to plant nutrition. Pea (Pisum sativum) was grown in CO2-enriched air (1000 cm 3 m3 CO2) during the entire vegetative phase, or grown in ambient air (340 cm3 m3 CO2), with different levels of nitrogen or phosphorus supply. Rubisco specific activity, abundance and small subunit transcript levels were unaltered at high N but declined at reduced N depending upon the degree of N deprivation. It is proposed that (a) a threshold value for the N status occurs in pea above which Rubisco is not down-regulated by high CO2 and (b) a high leaf level of soluble carbohydrates is not a sufficient condition to downregulate Rubisco in high CO2. Phosphoenolpyruvate (PEP) carboxylase decreased, and chloroplast phosphate (P)-translocator increased, in high CO2. In contrast to Rubisco, down-regulation of PEP carboxylase was alleviated by low N and enhanced by low P. The increase in the P-translocator was little affected by N but was accentuated by low P. The increase in the P-translocator is considered to be one way of alleviating low P conditions in the chloroplast and thus rebalancing carbon partitioning between starch and soluble carbohydrates and amino acids. It is proposed that acclimation of PEP carboxylase and P-translocator reflects adaptation to metabolic perturbations caused by high CO2.
The decimal code for the growth stages of cereals, devised by Zadoks, Chang & Konzak (1974), is reproduced with stylised drawings of selected stages of wheat, barley and oat plants. Expanded definitions of some of the descriptive phrases are designed to assist the application of the code to agrochemical research, development and use in the UK.
We summarize the impacts of elevated CO2 on the N concentration of plant tissues and present data to support the hypothesis that reductions in the quality of plant tissue commonly occur when plants are grown under elevated CO2. Synthesis of existing data showed an average 14% reduction of N concentrations in plant tissue generated under elevated CO2 regimes. However, elevated CO2 appeared to have different effects on the N concentrations of different plant types, as the reported reductions in N have been larger in C3 plants than in C4 plants and N2-fixers. Under elevated CO2 plants changed their allocation of N between above- and below-ground components: root N concentrations were reduced by an average of 9% compared to a 14% average reduction for above-ground tissues. Although the concentration of CO2 treatments represented a significant source of variance for plant N concentration, no consistent trends were observed between them.
The flours of 13 wheat varieties grown at different levels of nitrogen fertilisation were characterised by the quantitative determination of flour protein groups and gluten protein types using a combined extraction/HPLC procedure. The results demonstrate that the quantities of albumins and globulins were scarcely influenced by different nitrogen fertilisation, whereas those of gluten proteins (gliadins, glutenins) were strongly influenced. The effect on gliadins was more pronounced than on glutenins, as well as the effect on major protein types (α-gliadins, γ-gliadins, LMW subunits of glutenin) in comparison with minor types (ω-gliadins, HMW subunits of glutenin). The proportions of hydrophilic proteins (ω-gliadins, HMW subunits of glutenin) were increased by high levels of nitrogen and those of hydrophobic proteins (γ-gliadin, LMW subunits of glutenin) were decreased. The degree of the effects on both quantities and proportions of flour protein groups and gluten protein types was strongly dependent on the variety. © 1998 SCI.
Meta-analysis techniques were used to examine the effect of elevated atmospheric carbon dioxide [CO2] on the protein concentrations of major food crops, incorporating 228 experimental observations on barley, rice, wheat, soybean and potato. Each crop had lower protein concentrations when grown at elevated (540–958 μmol mol−1) compared with ambient (315–400 μmol mol−1) CO2. For wheat, barley and rice, the reduction in grain protein concentration was ∼10–15% of the value at ambient CO2. For potato, the reduction in tuber protein concentration was 14%. For soybean, there was a much smaller, although statistically significant reduction of protein concentration of 1.4%. The magnitude of the CO2 effect on wheat grains was smaller under high soil N conditions than under low soil N. Protein concentrations in potato tubers were reduced more for plants grown at high than at low concentrations of ozone. For soybean, the ozone effect was the reverse, as elevated CO2 increased the protein concentration of soybean grown at high ozone concentrations. The magnitude of the CO2 effect also varied depending on experimental methodology. For both wheat and soybean, studies performed in open-top chambers produced a larger CO2 effect than those performed using other types of experimental facilities. There was also indication of a possible pot artifact as, for both wheat and soybean, studies performed in open-top chambers showed a significantly greater CO2 effect when plants were rooted in pots rather than in the ground. Studies on wheat also showed a greater CO2 effect when protein concentration was measured in whole grains rather than flour. While the magnitude of the effect of elevated CO2 varied depending on the experimental procedures, a reduction in protein concentration was consistently found for most crops. These findings suggest that the increasing CO2 concentrations of the 21st century are likely to decrease the protein concentration of many human plant foods.
We report the identification of a full-length cDNA clone encoding cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) in the desiccation-tolerant plant Craterostigma plantagineum. The DNA sequence of the cDNA clone is homologous to cytosolic GAPDH cDNAs from other higher plants. The GAPDH transcript increases rapidly in abundance during dehydration or abscisic acid (ABA) treatment. The increase in mRNA levels is directly correlated with higher protein and enzyme levels. These results imply that enhanced rates of glycolysis are one of the immediate cellular responses to water deficit. This may be a mechanism by which the plant cell prepares for a demand of ATP and NADH2 during recovery.
In a three-year free-air CO2 enrichment study (Mini-FACE), spring wheat associated with typical arable weeds were grown under present and elevated atmospheric carbon dioxide concentrations [CO2] (ambient air+150 μmol mol-1). Analyses of plant stable carbon isotope ratios and in vivo measurements of leaf gas exchange were used to describe the CO2 effects on water relations. For most species examined elevated [CO2] significantly increased the intrinsic water-use efficiency (A/gs) as derived from carbon isotope analyses. In some of the species, seasonal averages of the ratio between leaf internal to atmospheric CO2 (ci/ca) were found to be significantly reduced by elevated [CO2]. Periodic leaf gas exchange measurements confirmed the increased water-use efficiency, but significant CO2 effects became evident only over the entire season by carbon isotope analysis. In both types of analysis conducted, spring wheat was found to react significantly different from all other species examined. The relation between A/gs and biomass production was significantly influenced by elevated [CO2] in all three years of the study. At the end of the drier growing seasons 2003 and 2004, the soil water content tended to be increased in the CO2 enriched plots indicating a water saving effect. These observations demonstrate the impact of elevated [CO2] on plant water relations with a likely positive feedback leading to higher soil water availability. Due to the differences in the CO2 responses of spring wheat compared to the weeds we suggest that rising [CO2] may cause shifts in the species composition of crop-weed communities.
Wheat (Triticum aestivum L.) is one of the most important agricultural crops worldwide. Due to its high content of starch and unique gluten proteins, wheat grain is used for many food and non-food applications. Although grain quality is an important topic for food and feed as well as industrial processing, the consequences of future increases in atmospheric carbon dioxide (CO2) concentrations on quality parameters such as nutritional and bread-making rheological properties are still unclear. Wheat productivity increases under CO2 enrichment. Concomitantly, the chemical composition of vegetative plant parts is often changed and grain quality is altered. In particular, the decrease in grain protein concentration and changes in protein composition may have serious economic and health implications. Additionally, CO2 enrichment affects amino acid composition and the concentrations of macro- and micro-elements. However, experimental results are often inconsistent. The present review summarises the results from numerous CO2 enrichment experiments using different exposure techniques in order to quantify the potential impacts of projected atmospheric CO2 levels on wheat grain yield and on aspects of grain composition relevant to processing and human nutrition.
Over the past decade, free-air CO2 enrichment (FACE) experiments have been conducted on wheat, perennial ryegrass, and rice, which are C3 grasses; sorghum, a C4 grass; white clover, a C3 legume; potato, a C3 forb with tuber storage; and cotton and grape, which are C3 woody perennials. Elevated CO2 increased photosynthesis, biomass, and yield substantially in C3 species, but little in C4. It decreased stomatal conductance in both C3 and C4 species and greatly improved water-use efficiency in all crops. Growth stimulations were as large or larger under water stress compared to well-watered conditions. At low soil N,stimulations of nonlegumes were reduced, whereas elevated CO2 strongly stimulated the growth of the clover legume at both ample and low N conditions. Roots were generally stimulated more than shoots. Woody perennials had larger growth responses to elevated CO2, but their reductions in stomatal conductance were smaller. Tissue N concentrations went down, while carbohydrate and some other carbon-based compounds went up, with leaves being the organs affected most. Phenology was accelerated slightly in most but not all species. Elevated CO2 affected some soil microbes greatly but not others, yet overall activity was stimulated. Detection of statistically significant changes in soil organic carbon in any one study was nearly impossible, yet combining results from several sites and years, it appeared that elevated CO2 did increase sequestration of soil carbon. Comparisons of the FACE results with those from earlier chamber-based results were consistent, which gives confidence that conclusions drawn from both types of data are accurate.
Nutrient element concentrations and grain quality were assessed in spring wheat grown under elevated CO2 concentrations and contrasting levels of tropospheric ozone at different nitrogen supply rates at several European sites. Carbon dioxide enrichment proved to affect nutrient concentrations in a complex manner. In green leaves, all elements (with exception of phosphorus and iron) decreased. In contrast, effects on the element composition of grains were restricted to reductions in nitrogen, calcium, sulphur and iron. Ozone exposure resulted in no significant effects on nutrient element concentrations in different tissues in the overall analysis. The nitrogen demand of green tissues was reduced due to CO2 enrichment as shown by reductions in the critical leaf nitrogen concentration and also enhanced nitrogen use efficiency. Reductions in the content of ribulose-bisphosphate carboxylase/oxygenase and repression of the photorespiratory pathway and reduced nitrogen allocation to enzymes driving the photosynthetic carbon oxidation cycle were chiefly responsible for this effect. Thus, nitrogen acquisition by the crop did not match carbon acquisition under CO2 enrichment. Since crop nitrogen uptake from the soil was already completed at anthesis, nitrogen allocated to the grain after anthesis originated from vegetative pools—causing grain nitrogen concentrations to decrease under CO2 enrichment (on average by 15% when CO2 concentrations increased from 360 to 680 μmol mol−1). Correspondingly, grain quality was reduced by CO2 enrichment. The Zeleny value, Hagberg value and dry/wet gluten content decreased significantly with increasing [CO2]. Despite the beneficial impact of CO2 enrichment on growth and yield of C3 cereal crops, declines in flour quality due to reduced nitrogen content are likely in a future, [CO2]-rich world.
Recent proteomic studies of the wheat grain have focused on the endosperm tissuedue to its importance to productivity and quality [1-3]. The gluten proteins are ofmajor interest in these studies, since they determine the characteristics of extensibility,elasticity, and gas-holding capacity that are unique to wheat flour doughs. The glutenProteins encompass-more than 80% of theendosperm protein and consist of gliadinsand glutenin subunits. The gliadins are a polymorphic collection of monomeric pro-teins soluble in 70% alcohol that are separated into a, y, and
Research comparing the biochemical composition of wheat grains from organic or conventional agriculture has used the targeted analytical approach. To obtain a more comprehensive record of the food's composition, we employed protein profiling techniques. Levels of 1049 proteins were recorded in wheat grains (Triticum aestivum L., cv. Titlis) of two growing seasons from a rigorously controlled field trial in Switzerland, containing organic and conventional plots. Levels of 25 proteins were different between organic and conventional wheat in both years. Storage proteins, enzymes of carbohydrate metabolism, a peroxidase, and proteins of unknown function were affected by the agricultural regime. Total protein content was lower in organic wheat. We consider these differences negligible with regard to nutrition in an average diet and propose that food quality of conventional and organic wheat grown in the field trial was equal. Applying various filters and calculations, one of which takes seasonal influences into account, 16 of the 25 proteins with different levels in organic and conventional wheat were retained. These 16 "diagnostic" proteins have the potential to afford a signature to prove authenticity of organic wheat.
A combined two-dimensional gel electrophoresis-mass spectrometry approach was utilized to identify over 250 proteins of wheat (Triticum aestivum L., cv. Butte 86) starchy endosperm that participate in 13 biochemical processes: ATP interconversion reactions, carbohydrate metabolism, cell division, cytoskeleton, lipid metabolism, nitrogen metabolism, protein synthesis/assembly, protein turnover, signal transduction, protein storage, stress/defense, transcription/translation, and transport. Endosperm protein populations were compared at early (10 days post-anthesis, dpa) and late (36 dpa) stages of grain development. Analysis of protein number and spot volume revealed that carbohydrate metabolism, transcription/translation, and protein synthesis/assembly were the principal endosperm functions at 10 dpa followed by nitrogen metabolism, protein turnover, cytoskeleton, cell division, signal transduction, and lipid metabolism. Carbohydrate metabolism and protein synthesis/assembly were also major functions at 36 dpa, but stress/defense and storage were predominant. The results provide insight into biochemical events taking place during wheat grain development and highlight the value of proteomics in characterizing complex biochemical processes. Further, the proteome maps will facilitate future studies addressing the effects of genetic and environmental factors on the development and quality of wheat grain.
This review summarizes current understanding of the mechanisms that underlie the response of photosynthesis and stomatal conductance to elevated carbon dioxide concentration ([CO2]), and examines how downstream processes and environmental constraints modulate these two fundamental responses. The results from free-air CO2 enrichment (FACE) experiments were summarized via meta-analysis to quantify the mean responses of stomatal and photosynthetic parameters to elevated [CO2]. Elevation of [CO2] in FACE experiments reduced stomatal conductance by 22%, yet, this reduction was not associated with a similar change in stomatal density. Elevated [CO2] stimulated light-saturated photosynthesis (Asat) in C3 plants grown in FACE by an average of 31%. However, the magnitude of the increase in Asat varied with functional group and environment. Functional groups with ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)-limited photosynthesis at elevated [CO2] had greater potential for increases in Asat than those where photosynthesis became ribulose-1,5-bisphosphate (RubP)-limited at elevated [CO2]. Both nitrogen supply and sink capacity modulated the response of photosynthesis to elevated [CO2] through their impact on the acclimation of carboxylation capacity. Increased understanding of the molecular and biochemical mechanisms by which plants respond to elevated [CO2], and the feedback of environmental factors upon them, will improve our ability to predict ecosystem responses to rising [CO2] and increase our potential to adapt crops and managed ecosystems to future atmospheric [CO2].
Summary 607
Acknowledgements 615
References 615
Recent breakthroughs in CO2 fumigation methods using free-air CO2 enrichment (FACE) technology have prompted comparisons between FACE experiments and ‘enclosure studies’ with respect to quantification of the effects of projected atmospheric CO2 concentrations on crop yields. On the basis of one such comparison, it was argued that model projections of future food supply (some of which are based on older enclosure data) may have significantly overestimated the positive effect of elevated CO2 concentration on crop yields and, by extension, food security. However, in the comparison, no effort was made to differentiate ‘enclosure study’ methodologies with respect to maintaining projected CO2 concentration or to consider other climatic changes (e.g. warming) that could impact crop yields. In this review, we demonstrate that relative yield stimulations in response to future CO2 concentrations obtained using a number of enclosure methodologies are quantitatively consistent with FACE results for three crops of global importance: rice (Oryza sativa), soybean (Glycine max) and wheat (Triticum aestivum). We suggest, that instead of focusing on methodological disparities per se, improved projections of future food supply could be achieved by better characterization of the biotic/abiotic uncertainties associated with projected changes in CO2 and climate and incorporation of these uncertainties into current crop models.
The continuing increase in atmospheric CO 2 concentration is predicted to enhance biomass production and to alter biochemical composition of plant tissues. In the present study, winter wheat ( Triticum aestivum L. cv. 'Batis') was grown under ambient air (BLOW, CO 2 concentration: 385 muL L (-1)) and free-air CO 2 enrichment (FACE, CO 2 concentration: 550 muL l (-1)) and two different nitrogen (N) fertilization levels (normal N supply: N100, 50% of normal N supply: N50). Mature kernels were milled into white flour and analyzed for the contents of crude protein, Osborne fractions, single gluten protein types and glutenin macropolymer. Elevated CO 2 caused significant reductions in crude protein and all protein fractions and types ( p < 0.001) except albumins and globulins. Effects were more pronounced in wheat samples supplied with normal amounts of N fertilizer. Crude protein was reduced by 14% (N100) and 9% (N50), gliadins by 20% and 13%, glutenins by 15% and 15% and glutenin macropolymer by 19% and 16%, respectively. Within gliadins, omega5-gliadins (-35/-22%) and omega1,2-gliadins (-27/-14%) were more affected than alpha-gliadins (-21/-13%) and gamma-gliadins (-16/-12%). Within glutenins, HMW subunits (-23/-18%) were more affected than LMW subunits (-12/-15%). According to these results, flour from high CO 2 grown grain will have a diminished baking quality. To our knowledge, these are the first results of elevated CO 2 concentrations impacts on wheat grain protein composition gained under relevant growing conditions at least for Central Europe.
Global climate projections Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change
- G A Meehl
- T F Stocker
- W D Collins
- P Friedlingstein
- A T Gaye
- J M Gregory
- A Kitoh
- R Knutti
- J M Murphy
- A Noda
- S C B Raper
- I G Watterson
- A J Weaver
- Z C Zhao
Meehl, G.A., Stocker, T.F., Collins, W.D., Friedlingstein, P., Gaye, A.T., Gregory, J.M., Kitoh, A., Knutti, R., Murphy, J.M., Noda, A., Raper, S.C.B., Watterson, I.G., Weaver, A.J., Zhao, Z.C., 2007. Global climate projections. In: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M., Miller, H.L. (Eds.), Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, pp. 748–846.
Structural analysis of XIP-I, a xylanase proteinaceous inhibitor from wheat
- F Payan
- R Flatman
- S Porciero
- G Williamson
- N Juge
- A Roussel
Payan, F., Flatman, R., Porciero, S., Williamson, G., Juge, N., Roussel, A., 2003. Structural analysis of XIP-I, a xylanase proteinaceous inhibitor from wheat. Biochemical Journal 372, 395–405.
Elevated CO 2 reduces the nitrogen concentration of plant tissues
- M F Cotrufo
- P Ineson
- A Scott
Cotrufo, M.F., Ineson, P., Scott, A., 1998. Elevated CO 2 reduces the nitrogen
concentration of plant tissues. Global Change Biology 4, 43–54.
Critical review: functional properties of wheat glutenin
- Weegels
Elevated CO2 reduces the nitrogen concentration of plant tissues
- Cotrufo
Structural analysis of XIP-I, a xylanase proteinaceous inhibitor from wheat
- Payan