Joaquim Albenisio Gomes Silveira

Universidade Federal do Ceará | UFC · Departamento de Bioquímica e Biologia Molecular

Plants contain three NADPH-thioredoxin reductases (NTR) located in the cytosol/mitochondria (NTRA/B) and the plastid (NTRC) with important metabolic functions. However, mutants deficient in all NTRs remained to be investigated. Here, we generated and characterised the triple Arabidopsis ntrabc mutant alongside with ntrc single and ntrab double muta...

This study tested the hypothesis that elevated CO 2 improves the growth of grapevine seedlings, achieving greater vigor and shortening the production time under salinity due to the best ionic homeostasis and oxidative protection. Seedlings were exposed to isolate and combined effects of CO 2 (ambient – 400 and elevated – 800 µmol mol − 1 ) and sali...

Chloroplast ascorbate peroxidases exert an important role in the maintenance of hydrogen peroxide levels in chloroplasts by using ascorbate as the specific electron donor. In this work, we performed a functional study of the stromal APX in rice (OsAPX7) and demonstrated that silencing of OsAPX7 did not impact plant growth, redox state, or photosynt...

In October 2020, at the peak of the COVID-19 pandemic, a group of young Brazilian photosynthesis researchers organized the 1st Brazilian Symposium on Photosynthesis. The event was free and online, with the presence of important guest speakers from all over the world, who discussed their recent works on topics related to the future and perspectives...

In October 2020, at the peak of the COVID-19 pandemic, a group of young Brazilian photosynthesis researchers organized the 1st Brazilian Symposium on Photosynthesis. The event was free and online, with the presence of important guest speakers from all over the world, who discussed their recent works on topics related to the future and perspectives...

High ammonium concentration is toxic for most plant species, but some rice cultivars are tolerant by mechanisms not understood yet. We tested the hypothesis that NH4⁺-tolerance in rice could be associated with an exclusion mechanism involving ammonium deposition on the oldest leaves after triggering localized senescence. An ammonium-tolerant cultiv...

Salinity affects plant productivity in all agricultural crops. In the Brazilian semiarid region, considered one of the most salinized areas in Brazil, the cultivation of cowpea beans (Vigna unguiculata) is of paramount importance for the region's economy and food security. However, the development of the plant roots is affected by the inherent sali...

Integrative mechanisms involving photosynthetic and antioxidant protection regulated by light intensity during in vitro and ex vitro plantlets acclimatization are poorly understood. Tobacco plantlets grown under in vitro and ex vitro environments were exposed to different light regimes to evaluate the role of photosynthesis and antioxidant protecti...

Infection with Cowpea severe mosaic virus (CPSMV) represents one of the main limitations for cowpea (Vigna unguiculata L. Walp.) productivity due to the severity of the disease symptoms, frequency of incidence, and difficulties in dissemination control. This study aimed to identify the proteins and metabolic pathways associated with the susceptibil...

Infection with Cowpea severe mosaic virus (CPSMV) represents one of the main limitations for cowpea (Vigna unguiculata L. Walp.) productivity due to the severity of the disease symptoms, frequency of incidence, and difficulties in dissemination control. This study aimed to identify the proteins and metabolic pathways associated with the susceptibil...

Aims Understanding mechanisms underlying N use efficiency (NUE) after luxury consumption and nitrate deprivation is crucial to crop productivity. The aim was to elucidate the importance of photosynthesis, assimilatory nitrate reduction and N-reserve remobilization to NUE in cotton. Methods Plants were exposed to three conditions in nutrient soluti...

The aim of this study was to evaluate the effects of elevated CO2 concentration on acclimation mechanisms related to gas exchange, photochemical activity, photorespiration, and oxidative protection in cashew plants exposed to salinity. Thirty-day-old cashew plants were irrigated with nutrient solution without (control) or with supplemental NaCl (10...

Photosynthesis involves the conversion of sunlight energy into stored chemical energy, which is achieved through electron transport along a series of redox reactions. Excess photosynthetic electron transport might be dangerous due to the risk of molecular oxygen reduction, generating reactive oxygen species (ROS) over-accumulation. Avoiding excess...

Mechanisms involving ammonium toxicity, excess light, and photosynthesis are scarcely known in plants. We tested the hypothesis that high NH4+ supply in presence of high light decreases photosynthetic efficiency of rice plants, an allegedly tolerant species. Mature rice plants were previously supplied with 10 mM NH4+ or 10 mM NO3− and subsequently...

Catalase (CAT) is a crucial enzyme to control the excess peroxisomal H2O2 produced during photorespiration. In many plant species, this enzymatic activity decreases in response to drought but its specific role in photosynthesis and redox metabolism is still poorly understood. In this study was tested the hypothesis that photosynthetic and oxidative...

The mechanisms by which nitrate assimilation might favour photorespiration and how these pathways could cooperatively improve photosynthesis are still little understood, especially under excess light. Here, we tested the hypothesis that increased assimilatory nitrate reduction is able to stimulate photorespiration and these two processes together a...

Natural growth environments commonly include fluctuating conditions that can disrupt the photosynthetic energy balance and induce photoinhibition through inactivation of the photosynthetic apparatus. Photosystem II (PSII) photoinhibition is efficiently reversed by the PSII repair cycle, whereas photoinhibited photosystem I (PSI) recovers much more sl...

In nature, plants are simultaneously challenged by biotic and abiotic stresses. However, little is known about the effects of these combined stresses for most crops. This work aimed to evaluate the responsed of the virus-resistant cowpea genotype BRS-Marataoã to the exposure of salt stress combined with CPSMV infection. Cowpea plants were exposed t...

Life on earth depends on the presence of photoautotrophic organisms that are able to input carbon into the ecosystems through the process of photosynthesis which, with a few specialized exceptions, takes place within the chloroplast. This organelle contains the most complex redox system in plants being composed of numerous players including thiol r...

Retrograde signalling pathways, triggered by changes in cellular redox homeostasis, remain poorly understood. Transformed rice plants that are deficient in peroxisomal APX4 (RNAiOsAPX4) exhibit more effective protection of photosynthesis than controls when catalase (CAT) is inhibited, but the mechanisms involved have not been characterised. An in-d...

Rice is one of the world's most important crops and an excellent model system for understanding the interaction between genes and environmental changes. However, its productivity is often challenged by abiotic stresses, which results in the accumulation of reactive oxygen species. Glutathione peroxidases are part of the mechanism by which plants fa...

Although a great number of studies have focused on salt tolerance in cultivated plants, the physiological mechanisms involved in this process are still not completely understood. This study aimed to perform an integrated physiological analysis in two cultivars of soybean, M-Soy 8222 (salinity sensitive) and M9144 RR (salinity tolerant). Soybean pla...

Chloroplast APX isoforms display controversial roles as H2O2 scavengers and signaling players in response to abiotic stress and conclusive results are lacking. We tested the hypothesis that thylakoidal APX displays an important role for drought tolerance, especially by regulating abundance of essential protein species. For this, OsApx8 RNAi-silence...

This study aimed to evaluate the photosynthetic and antioxidant responses of Jatropha curcas plants exposed to heat stress applied simultaneously in both shoots and roots and solely in each tissue. Thirty-day-old plants were transferred to two growth chambers, where they were subjected to 27 or 42 °C. In each growth chamber, the root system was iso...

In rice (Oryza sativa L.) there are two chloroplast ascorbate peroxidases isoforms, OsAPX7 (stromal) and OsAPX8 (thylakoidal). Previous works demonstrated that double silencing of OsAPX7 and OsAPX8 led to differences in photosynthetic parameters in stress conditions. Nevertheless, both APX encoding genes present contrasting expression patterns in r...

To mitigate the deleterious effects of abiotic stress, the use of plant growth-promoting bacteria (PGPB) along with diazotrophic bacteria has been increasing. The objectives of this study were to investigate the key enzymes related to nitrogen and carbon metabolism in the biological nitrogen fixation process and to elucidate the activities of these...

Toxicity caused by high concentrations of ascorbic acid (AA) has been widely reported in animal cells but is scarcely described in plants. In this study, rice plants deficient (knockdown) in two chloroplast ascorbate peroxidases (APX7/8) and non-transformed (NT) were exposed to wide exogenous AA concentrations in the presence of low light and high...

We tested the hypothesis that effective antioxidant and photoprotective mechanisms are able to avoid photodamage induced by prolonged water deficit (WD) followed by high light (HL). We employed cashew plants (Anacardium occidentale L.), a semiarid adapted species, as a model plant. WD-plants exposed to HL did not show alterations in maximum quantum...

Soil salinity is an important abiotic stress worldwide, and salt-induced oxidative stress can have detrimental effects on the biological nitrogen fixation. We hypothesized that co-inoculation of cowpea plants with Bradyrhizobium and plant growth-promoting bacteria would minimize the deleterious effects of salt stress via the induction of enzymatic...

The flexibility between C4 photosynthetic sub-types NADP-malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PEPCK), recently identified in some C4 species, confers high photosynthetic efficiency under varying light conditions. Theoretically, PEPCK decarboxylation uses less quanta per CO2 fixed than NADP-ME, suggesting an increase in PEPC...

Ricinus communis is one of the major commercial non-edible oilseed crops grown in semiarid and arid environments worldwide and is reported as a drought tolerant species. Surprisingly, little is known about the mechanisms achieving this tolerance, especially in relation to photoprotection. The aim of this study was to analyze the association of the...

H2O2, which is continually produced by aerobic metabolism, is a cytotoxic molecule when in high levels. However, low levels can act as a signaling molecule able to regulate the expression of stress responses, senescence, programmed cell death, plant growth, and development. Ascorbate peroxidase (APX) enzyme plays an essential role in the control of...

Biological significance: This is a pioneering study in which an incompatible relationship between a resistant cowpea and Cowpea severe mosaic virus (CPSMV) was conducted to comparatively evaluate proteomic profiles by Gel-free/label-free methodology and some physiological and biochemical parameters to shed light on how a resistant cowpea cultivar...

Although plant physiological responses to drought have been widely studied, the interaction between photoprotection, photorespiration and antioxidant metabolism in water‐stressed plants is scarcely addressed. This study aimed to evaluate the physiological adjustments preserving photosynthesis and growth in two plant species with different tolerance...

Key message The seed treatment of a CPSMV-susceptible cowpea genotype with the mutagenic agent EMS generated mutagenized resistant plantlets that respond to the virus challenge by activating biochemical and physiological defense mechanisms. Abstract Cowpea is an important crop that makes major nutritional contributions particularly to the diet of...

Spraying sucrose inhibits photosynthesis by impairing Rubisco activity and stomatal conductance (gs), whereas increasing sink demand by partially darkening the plant stimulates sugarcane photosynthesis. We hypothesized that the stimulatory effect of darkness can offset the inhibitory effect of exogenous sucrose on photosynthesis. Source-sink relati...

The physiological and biochemical responses of a drought tolerant, virus-susceptible cowpea genotype exposed to drought stress (D), infected by Cowpea severe mosaic virus (CPSMV) (V), and to these two combined stresses (DV), at 2 and 6 days post viral inoculation (DPI), were evaluated. Gas exchange parameters (net photosynthesis, transpiration rate...

Salinity and osmotic stress trigger distinct signals in roots, which might induce differences in antioxidant responses. To clarify these relationships, transgenic rice plants silenced in both cytosolic ascorbate peroxidases (apx1/2) and non-transformed (NT) were exposed to iso-osmotic concentrations of NaCl and mannitol. Under both stress condition...

Salinity remarkably inhibits NO3- uptake but the mechanisms are not well understood. This study was addressed to elucidate the role of ionic and osmotic components of salinity on NO3- influx and efflux employing classic kinetic involving low affinity transport system (LATS) and high affinity transport system (HATS). In presence of KCl, NaCl, and Na...

The physiological role of plant mitochondrial glutathione peroxidases is scarcely known. This study attempted to elucidate the role of a rice mitochondrial isoform (GPX1) in photosynthesis under normal growth and salinity conditions. GPX1 knockdown rice lines (GPX1s) were tested in absence and presence of 100 mM NaCl for six days. Growth reduction...

This study evaluated the capacity of high relative humidity associated with K+ supply in mitigating harmful effects caused by salt stress on physiological parameters of Jatropha curcas plants. The plants were subjected to four different treatments (K0Na0, K0Na1, K1Na0 and K1Na1) and two different levels of humidity, low (40%) and high (80%), in cha...

Water deficit is an important exogenous factor that enhances the influx of sucrose into sugarcane (Saccharum spp.) stem internodes during ripening, when photosynthetic ability in supplying sinks is essential. The aim of this study was to test the hypothesis that drought tolerance in sugarcane is associated with an effective antioxidant protection d...

Plant glutathione peroxidases (GPX) catalyze the reduction of H 2 O 2 or organic hydroperoxides to water, mitigating the toxicity of these compounds to cells. In rice plants, the GPX gene family is composed of five members that are distributed in a range of sub-cellular compartments, including cytosol, mitochondria, chloroplasts, or endoplasmic ret...

The objectives of this work were to evaluate the organic and inorganic solutes accumulation and measure their contribution to the osmotic adjustment of physic nut (Jatropha curcas L.) leaves under salinity. The experiment was carried out using a completely randomized design with five treatments (0, 25, 50, 75, and 100 mmol L-1 of NaCl) and four rep...

This study assessed the capacity of Jatropha curcas plants to physiologically adjust to salinity. The seedlings were exposed to increasing NaCl concentrations (25, 50, 75 and 100 mM) for 15 days. The treatment free-NaCl was adopted as control. The shoot dry weight was strongly reduced by NaCl levels reaching values from 35% to 65% in the 25 to 100...

The physiological role of peroxisomal ascorbate peroxidases (pAPX) is unknown; therefore, we utilized pAPX4 knockdown rice and catalase (CAT) inhibition to assess its role in CAT compensation under high photorespiration. pAPX4 knockdown induced co-suppression in the expression of pAPX3. The rice mutants exhibited metabolic changes such as lower CAT...

Higher plants display different adaptive strategies in photosynthesis to cope with abiotic stress. In this study, photosynthetic mechanisms and water relationships displayed byJatropha curcasL. (physic nuts) andRicinus communisL. (castor bean), in response to variations in environmental conditions, were assessed.R. communis showed higher CO2 assimi...

O feijao-caupi e uma leguminosa muito importante para a populacao brasileira, principalmente por ser cultivado na regiao Nordeste, muitas vezes em areas salinizadas. Assim, o objetivo do trabalho foi avaliar o efeito do estresse salino no crescimento (massa seca) e particao de ions (Na + , K + e Cl – ) em feijao-caupi ( Vigna unguiculata ), visando...

The effects of salicylic acid (SA) and salinity on growth, photosynthesis, and antioxidative protection were studied in the leaves of Jatropha curcas. Twenty-three-day-old plants were exposed to 0 (control) and 100 mM NaCl and sprayed with 5 mM SA. The salinity treatment reduced the growth and gas exchange parameters of the species, but when the ex...

The present study aimed to determine if photosynthesis interferes with the modulation of antioxidant compounds in young Euterpe oleracea plants exposed to water deficiencies. A factorial, completely randomised experimental design was employed, and two water conditions (water deficit and control) and four evaluation points (0, 6, 12 and 18 days) wer...

Plant glutathione peroxidases (GPX) catalyze the reduction of H2O2 or organic hydroperoxides to water, mitigating the toxicity of these compounds to cells. In rice plants, the GPX gene family is composed of five members that are distributed in a range of sub-cellular compartments including cytosol, mitochondria, chloroplasts, or endoplasmic reticul...

Introduction Jatropha curcas L., more commonly known as the physic or purge nut, is an oilseed plant species that is native to tropical America and now thrives in many parts of the tropics and semiarid regions in Africa, Asia and South America. This species grows in marginal areas frequently subjected to dry and hot conditions and associated with p...

N 2 symbiotic fixation efficiency by legume nodules involves several metabolic processes and requires favorable environmental conditions. The nitrogenase enzymatic complex demands high energy and depends on oxidative reactions to generate reducing power and ATP. These oxidative reactions are accomplished via O 2 consumption in the electron transpor...

Manejo da salinidade na agricultura: Estudos básicos e aplicados ISBN 978-85-7563-489-9 Fortaleza -CE 2010 Introdução Efeitos do estresse salino e principais respostas das plantas Efeitos osmóticos e efeitos iônicos Mecanismos da inibição do crescimento de plantas pela salinidade Mecanismos biomoleculares da resistência a salinidade Considerações i...

The biochemical mechanisms underlying the involvement of cytosolic APXs in photosynthesis are still unknown. In this study, rice plants doubly silenced in these genes (APX1/2) were exposed to moderate light (ML) and high light (HL) to assess the role of cAPXs in photosynthetic efficiency. APX1/2 mutants that were exposed to ML overexpressed seven a...