Publications (14)34.64 Total impact
-
Article: Drought impacts mineral contents in Andean potato cultivars
[show abstract] [hide abstract]
ABSTRACT: Mineral micro- and macronutrients in tubers of 21 Andean potato cultivars were investigated in a field trial under control and drought conditions. Mineral concentrations in potato tubers were highly variable between genotypes; some were significantly and positively correlated with each other, the most noteworthy associations being Na–Ca, Mn–Mg and Zn–Fe, in both control and drought-stressed plants. Overall, increasing yields are related to decreased concentrations of some nutrients, albeit some higher-yielding cultivars also displayed important concentrations of nutrients in their tubers. The most striking result was the increase in the concentration of the majority of the analysed cations in a large number of cultivars in response to water depletion; some of them, such as K, may be related to water homeostasis and/or to sucrose loading and unloading in phloem sap. Tuber mineral concentrations were not related to drought tolerance in terms of tuber productivity. Interestingly, yield loss under drought was not correlated with yield potential under control conditions. Identification of cultivars such as 703264 and 701106 able to maintain good yield stability in association with high mineral contents under water deprivation is of particular interest, especially in view of the importance of potato as a staple crop and the expansion of its cultivation to non-optimal cultivation areas in the context of changing climatic conditions.Journal of Agronomy and Crop Science 06/2012; 198(3):196-206. · 2.43 Impact Factor -
Article: Field Screening for Variation of Drought Tolerance in Solanum tuberosum L. by Agronomical, Physiological and Genetic Analysis
[show abstract] [hide abstract]
ABSTRACT: Solanum tuberosum cultivars, Solanum tuberosum × Solanum tuberosum subsp. andigena hybrids and breeding clones with different time to maturity were screened for drought tolerance in field plots located in the coastal desert of Peru. Variation for drought tolerance was illustrated by clone-dependent differences in tuber yield and yield loss under drought conditions. Neither changes in stomatal conductance nor maximum quantum yield of chlorophyll fluorescence were quantitatively associated with yield or yield loss under drought. In contrast, relative vegetation index (reflectance at 800nm / reflectance at 650nm) and normalized difference vegetation index [(reflectance at 800nm – reflectance at 650nm) / (reflectance at 800nm + reflectance at 650nm)] on day 25 and day 40 after drought were correlated with yield. The vegetation indices are related to leaf area index and above ground biomass, which appeared to be major determinants for yield in the tested cultivars under drought. Nitrate reductase activity was significantly decreased in drought-exposed plants, but activity depletion was independent of yield or yield maintenance. Putative drought tolerance genes were differentially expressed in leaves of water stressed genotypes. Induction of the protein phosphatase 2C gene was positively associated with yield maintenance under drought. Furthermore, tolerant cultivars expressed DREB transcription factor to a higher extent than susceptible cultivars. By ranking 16 cultivars with respect to yield maintenance under drought, we identified canopy size and up-regulation of drought tolerance genes as contributors to drought tolerance.Potato Research 04/2012; 50(1):71-85. -
Article: Carbohydrate metabolism and cell protection mechanisms differentiate drought tolerance and sensitivity in advanced potato clones (Solanum tuberosum L.).
[show abstract] [hide abstract]
ABSTRACT: In potatoes and many other crops, drought is one of the most important environmental constraints leading to yield loss. Development of drought-tolerant cultivars is therefore required for maintaining yields under climate change conditions and for the extension of agriculture to sub-optimal cropping areas. Drought tolerance mechanisms have been well described for many crop plants including Native Andean potato. However, knowledge on tolerance traits suitable for commercial potato varieties is scarce. In order to describe drought tolerance mechanisms that sustain potato yield under water stress, we have designed a growth-chamber experiment with two Solanum tuberosum L. cultivars, the more drought tolerant accession 397077.16, and the sensitive variety Canchan. After 21 days of drought exposure, gene expression was studied in leaves using cDNA microarrays. The results showed that the tolerant clone presented more differentially expressed genes than the sensitive one, suggesting greater stress response and adaptation. Moreover, it exhibited a large pool of upregulated genes belonging to cell rescue and detoxication such as LEAs, dehydrins, HSPs, and metallothioneins. Transcription factors related to abiotic stresses and genes belonging to raffinose family oligosaccharide synthesis, involved in desiccation tolerance, were upregulated to a greater extent in the tolerant clone. This latter result was corroborated by biochemical analyses performed at 32 and 49 days after drought that showed an increase in galactinol and raffinose especially in clone 397077.16. The results depict key components for the drought tolerance of this advanced potato clone.Functional & Integrative Genomics 01/2011; 11(2):275-91. · 3.83 Impact Factor -
Article: A sweet potato gene index established by de novo assembly of pyrosequencing and Sanger sequences and mining for gene-based microsatellite markers.
[show abstract] [hide abstract]
ABSTRACT: Sweetpotato (Ipomoea batatas (L.) Lam.), a hexaploid outcrossing crop, is an important staple and food security crop in developing countries in Africa and Asia. The availability of genomic resources for sweetpotato is in striking contrast to its importance for human nutrition. Previously existing sequence data were restricted to around 22,000 expressed sequence tag (EST) sequences and ~ 1,500 GenBank sequences. We have used 454 pyrosequencing to augment the available gene sequence information to enhance functional genomics and marker design for this plant species. Two quarter 454 pyrosequencing runs used two normalized cDNA collections from stems and leaves from drought-stressed sweetpotato clone Tanzania and yielded 524,209 reads, which were assembled together with 22,094 publically available expressed sequence tags into 31,685 sets of overlapping DNA segments and 34,733 unassembled sequences. Blastx comparisons with the UniRef100 database allowed annotation of 23,957 contigs and 15,342 singletons resulting in 24,657 putatively unique genes. Further, 27,119 sequences had no match to protein sequences of UniRef100database. On the basis of this gene index, we have identified 1,661 gene-based microsatellite sequences, of which 223 were selected for testing and 195 were successfully amplified in a test panel of 6 hexaploid (I. batatas) and 2 diploid (I. trifida) accessions. The sweetpotato gene index is a useful source for functionally annotated sweetpotato gene sequences that contains three times more gene sequence information for sweetpotato than previous EST assemblies. A searchable version of the gene index, including a blastn function, is available at http://www.cipotato.org/sweetpotato_gene_index.BMC Genomics 10/2010; 11:604. · 4.07 Impact Factor -
Article: Identification of drought-responsive compounds in potato through a combined transcriptomic and targeted metabolite approach.
[show abstract] [hide abstract]
ABSTRACT: Two potato clones (Solanum tuberosum L.) of the Andean cultivar group, called Sullu and SS2613, with different drought-tolerance phenotypes were exposed to a continuously increasing drought stress in a field trial. At the physiological level, while relative leaf water contents were similar in both clones, osmotic potential was lower in Sullu and declined more strongly during drought compared with SS2613. In the drought-stressed plants, tuber yield was reduced by about 70% compared with control plants in both clones. Potato cDNA microarrays and target metabolite analysis were performed on leaves sampled at several time-points after the onset of drought. At the transcriptomic level, photosynthesis-related genes were already strongly repressed in Sullu after 28 d of withholding irrigation and even more strongly after a longer stress duration, whereas, in SS2613, repression occurred only after 49 d of soil drying; similarly, a strong perturbation of carbohydrate-related genes was observed in Sullu. At the metabolite level, differential accumulation of osmotically active solutes was observed between the two cultivars; indeed, in Sullu, contents of galactose, inositol, galactinol, proline, and proline analogues were higher upon drought stress compared with SS2613. These results point to different drought responses in the cultivars at the leaf level, with, however, similar tuber yield reductions. The previously shown tolerant clone Sullu lost part of its tolerance under the experimental conditions used here; it was, however, able to maintain an absolute yield three times higher than SS2613.Journal of Experimental Botany 05/2010; 61(9):2327-43. · 5.36 Impact Factor -
Article: A sweetpotato gene index established by de novo assembly of pyrosequencing and Sanger sequences and mining for gene-based microsatellite markers
[show abstract] [hide abstract]
ABSTRACT: Abstract Background Sweetpotato (Ipomoea batatas (L.) Lam.), a hexaploid outcrossing crop, is an important staple and food security crop in developing countries in Africa and Asia. The availability of genomic resources for sweetpotato is in striking contrast to its importance for human nutrition. Previously existing sequence data were restricted to around 22,000 expressed sequence tag (EST) sequences and ~ 1,500 GenBank sequences. We have used 454 pyrosequencing to augment the available gene sequence information to enhance functional genomics and marker design for this plant species. Results Two quarter 454 pyrosequencing runs used two normalized cDNA collections from stems and leaves from drought-stressed sweetpotato clone Tanzania and yielded 524,209 reads, which were assembled together with 22,094 publically available expressed sequence tags into 31,685 sets of overlapping DNA segments and 34,733 unassembled sequences. Blastx comparisons with the UniRef100 database allowed annotation of 23,957 contigs and 15,342 singletons resulting in 24,657 putatively unique genes. Further, 27,119 sequences had no match to protein sequences of UniRef100database. On the basis of this gene index, we have identified 1,661 gene-based microsatellite sequences, of which 223 were selected for testing and 195 were successfully amplified in a test panel of 6 hexaploid (I. batatas) and 2 diploid (I. trifida) accessions. Conclusions The sweetpotato gene index is a useful source for functionally annotated sweetpotato gene sequences that contains three times more gene sequence information for sweetpotato than previous EST assemblies. A searchable version of the gene index, including a blastn function, is available at http://www.cipotato.org/sweetpotato_gene_index.BMC Genomics. 01/2010; -
Conference Proceeding: Pyrosequencing Of Sweetpotato (Ipomoea batatas) Transcriptome
PAG (Plant and Animal Genomics Conference)PAG (Plant and Animal Genomics Conference), San Diego; 01/2010 -
Article: Gene expression changes related to the production of phenolic compounds in potato tubers grown under drought stress.
[show abstract] [hide abstract]
ABSTRACT: Polyphenols represent a large family of plant secondary metabolites implicated in the prevention of various diseases such as cancers and cardiovascular diseases. The potato is a significant source of polyphenols in the human diet. In this study, we examined the expression of thirteen genes involved in the biosynthesis of polyphenols in potato tubers using real-time RT-PCR. A selection of five field grown native Andean cultivars, presenting contrasting polyphenol profiles, was used. Moreover, we investigated the expression of the genes after a drought exposure. We concluded that the diverse polyphenolic profiles are correlated to variations in gene expression profiles. The drought-induced variations of the gene expression was highly cultivar-specific. In the three anthocyanin-containing cultivars, gene expression was coordinated and reflected at the metabolite level supporting a hypothesis that regulation of gene expression plays an essential role in the potato polyphenol production. We proposed that the altered sucrose flux induced by the drought stress is partly responsible for the changes in gene expression. This study provides information on key polyphenol biosynthetic and regulatory genes, which could be useful in the development of potato varieties with enhanced health and nutritional benefits.Phytochemistry 09/2009; 70(9):1107-16. · 3.35 Impact Factor -
Conference Proceeding: Development of Genetic and Genomic Resources for Breeding Improved Sweetpotato
ISTRC Symposium. 15th Triennial Symposium of the International Society for Tropical Root Crops, Lima, Peru, Nov. 2-6, 2009ISTRC Symposium. 15th Triennial Symposium of the International Society for Tropical Root Crops, Lima, Peru, Nov. 2-6, 2009; 01/2009 -
Article: Modification of the health-promoting value of potato tubers field grown under drought stress: emphasis on dietary antioxidant and glycoalkaloid contents in five native andean cultivars (Solanum tuberosum L.).
[show abstract] [hide abstract]
ABSTRACT: The effects of drought stress on dietary antioxidant and glycoalkaloid contents in potato tubers were investigated using a selection of five native Andean cultivars. Both freshly harvested and 4 month-stored tubers were analyzed. Responses to drought stress were highly cultivar-specific. The antioxidant contents of the yellow tuber-bearing cultivars (Sipancachi and SS-2613) were weakly affected by the drought treatment, whereas the pigmented cultivars demonstrated highly cultivar-dependent variations. A drastic reduction of anthocyanins and other polyphenols was revealed in the red- (Sullu) and purple-fleshed (Guincho Negra) cultivars, whereas an increase was shown in the purple-skinned and yellow-fleshed cultivar (Huata Colorada). The hydrophilic antioxidant capacity (evaluated by Folin-Ciocalteu and H-oxygen radical absorbance capacity assays) was highly correlated with the polyphenol content and followed, therefore, the same behavior upon drought. Carotenoid contents, including beta-carotene, as well as vitamin E, tended to increase or remain stable following drought exposure, except for the cultivar Sullu, in which the level of these lipophilic antioxidants was decreased. Vitamin C contents were not affected by drought with the exception of Guincho Negra, in which the level was increased. These variations of health-promoting compounds were associated with increased or stable levels of the toxic glycoalkaloids, alpha-solanine and alpha-chaconine. Storage at 10 degrees C for 4 months tended to decrease the concentrations of all dietary antioxidants, except those of vitamin E. This storage also reduced the drought-induced variations observed in freshly harvested tubers. These results were discussed in terms of their implications for human diet and health as well as in plant stress defense mechanisms.Journal of Agricultural and Food Chemistry 01/2009; 57(2):599-609. · 2.82 Impact Factor -
Article: Physiological and molecular adaptations to drought in Andean potato genotypes.
[show abstract] [hide abstract]
ABSTRACT: The drought stress tolerance of two Solanum tuberosum subsp. andigena landraces, one hybrid (adgxtbr) and Atlantic (S. tuberosum subsp. tuberosum) has been evaluated. Photosynthesis in the Andigena landraces during prolonged drought was maintained significantly longer than in the Tuberosum (Atlantic) line. Among the Andigena landraces, 'Sullu' (SUL) was more drought resistant than 'Negra Ojosa' (NOJ). Microarray analysis and metabolite data from leaf samples taken at the point of maximum stress suggested higher mitochondrial metabolic activity in SUL than in NOJ. A greater induction of chloroplast-localized antioxidant and chaperone genes in SUL compared with NOJ was evident. ABA-responsive TFs were more induced in NOJ compared with SUL, including WRKY1, mediating a response in SA signalling that may give rise to increased ROS. NOJ may be experiencing higher ROS levels than SUL. Metabolite profiles of NOJ were characterized by compounds indicative of stress, for example, proline, trehalose, and GABA, which accumulated to a higher degree than in SUL. The differences between the Andigena lines were not explained by protective roles of compatible solutes; hexoses and complex sugars were similar in both landraces. Instead, lower levels of ROS accumulation, greater mitochondrial activity and active chloroplast defences contributed to a lower stress load in SUL than in NOJ during drought.Journal of Experimental Botany 02/2008; 59(8):2109-23. · 5.36 Impact Factor -
Article: MOLECULAR AND PHYSIOLOGICAL ADAPTATION TO PROLONGED DROUGHT STRESS IN THE LEAVES OF TWO ANDEAN POTATO GENOTYPES
[show abstract] [hide abstract]
ABSTRACT: Responses to prolonged drought and recovery from drought of two South American potato (Solanum tuberosum L. ssp. andigena (Juz & Buk) Hawkes) landraces, Sullu and Ccompis were compared under field conditions. Physiological and biomass measurements, yield analysis, the results of hybridisation to a potato microarray platform (44 000 probes) and metabolite profiling were used to characterise responses to water deficit. Drought affected shoot and root biomass negatively in Ccompis but not in Sullu, whereas both genotypes maintained tuber yield under water stress. Ccompis showed stronger reduction in maximum quantum yield under stress than Sullu, and less decrease in stomatal resistance. Genes associated with PSII functions were activated during recovery in Sullu only. Evidence for sucrose accumulation in Sullu only during maximum stress and recovery was observed, in addition to increases in cell wall biosynthesis. A depression in the abundance of plastid superoxide dismutase transcripts was observed under maximum stress in Ccompis. Both sucrose and the regulatory molecule trehalose accumulated in the leaves of Sullu only. In contrast, in Ccompis, the raffinose oligosaccharide family pathway was activated, whereas low levels of sucrose and minor stress-mediated changes in trehalose were observed. Proline, and expression of the associated genes, rose in both genotypes under drought, with a 3-fold higher increase in Sullu than in Ccompis. The results demonstrate the presence of distinct molecular and biochemical drought responses in the two potato landraces leading to yield maintenance but differential biomass accumulation in vegetative tissues.Functional Plant Biology 01/2008; 35(8):669. · 2.93 Impact Factor -
Article: Capturing candidate drought tolerance traits in two native Andean potato clones by transcription profiling of field grown plants under water stress.
[show abstract] [hide abstract]
ABSTRACT: Candidate traits for drought tolerance were targeted by analyzing water stress responses in two moderately drought-tolerant native Andean potato clones, SA2563 and Sullu (Solanum tuberosum L. subsp, andigena (Juz, Bukasov) Hawkes) under field conditions. SA2563 exhibited increased root growth under drought, while Sullu retained a higher relative leaf water content. Gene expression profiling using the TIGR 10 K microarray revealed 1713 significantly differentially expressed genes, 186 of these genes were up-regulated in both clones. In addition to these commonly up-regulated genes, each clone induced a specific gene set in response to drought. Gene expression and metabolite analysis pinpointed candidate traits for drought tolerance present either in one or both of the clones under investigation. These traits included osmotic adjustment, changes in carbohydrate metabolism, membrane modifications, strengthening of cuticle and cell rescue mechanisms, such as detoxification of oxygen radicals and protein stabilization. Many of the up-regulated genes have been identified previously in laboratory studies on model plants using shock treatments, and the present study confirms the importance of these factors under field conditions.Plant Physiology and Biochemistry 10/2007; 45(9):673-90. · 2.84 Impact Factor -
Article: Proline accumulation and real time PCR expression analysis of genes encoding enzymes of proline metabolism in relation to drought tolerance in Andean potato
[show abstract] [hide abstract]
ABSTRACT: Six potato varieties belonging to four different sub-species were submitted to drought stress during tuberization under controlled field conditions, resulting in contrasting responses of the genotypes to water stress with yield losses varying between 27 and 75%. In all clones free proline accumulated under drought, however, proline levels increased earlier in drought-susceptible varieties than in more tolerant ones. The expression of two key genes in proline metabolism, Δ1-pyrroline-5-carboxylate synthase and proline dehydrogenase, was monitored in the leaves of the experimental plants by real time PCR 23 and 42days after drought onset. Expression of both enzymes did not correlate with the proline levels found in leaf tissue indicating that mechanisms other than transcription participate in the regulation of proline accumulation in potato leaves.Acta Physiologiae Plantarum 01/2007; 29(1):19-26. · 1.64 Impact Factor
Top co-authors
Top Journals
Institutions
-
2010–2011
-
Public Research Centre "Gabriel Lippmann"
- Environment and Agro-Biotechnologies Department (EVA)
Belvaux, District de Luxembourg, Luxembourg -
San Diego Zoo
San Diego, CA, USA
-
-
2007
-
Consultative Group on International Agricultural Research
- International Potato Center (CIP)
Washington, D. C., DC, USA
-
