Drought Tolerance In Cowpea Research Articles

68 A stress-inducible gene for neoxanthin cleavage enzyme involved in abscisic-acid biosynthesis under water stress in drought tolerant cowpea

68 A stress-inducible gene for neoxanthin cleavage enzyme involved in abscisic-acid biosynthesis under water stress in drought tolerant cowpea

A stress-inducible gene for neoxanthin cleavage enzyme involved in abscisic-acid biosynthesis under water stress in drought tolerant cowpea.

A stress-inducible gene for neoxanthin cleavage enzyme involved in abscisic-acid biosynthesis under water stress in drought tolerant cowpea.

Characterization of two cDNAs for novel drought-inducible genes in the highly drought-tolerant cowpea

Ten cDNAs for drought-inducible genes were isolated using differential screening of a cDNA library prepared from 10-hr dehydrated cowpea plants,Vigna unguiculata (S. Iuchi, K. Yamaguchi-Shinozaki, T. Urao, T. Terao, K. Shinozaki; Plant Cell Physiology, 1996 in press). Two of the cDNA clones, designated CPRD12 and CPRD46, were sequenced and characterized. The CPRD12 and CPRD46 cDNAs encode putative proteins related to nonmetallo-short-chain alcohol dehydrogenase (CPRD12) and chloroplastic lipoxygenase (CPRD46). Northern blot analysis revealed that these genes are induced by high-salinity stress and exogenous abscisic acid, but not by cold stress. The CPRD46 gene is also responsive to heat stress and methyl jasmonate and salicylic acid. Genomic Southern blot analysis suggested that CPRD12 constitutes a small gene family, but that CPRD46 is a single copy gene. We discuss the possible functions of these two CPRD gene products under drought stress.

Novel drought-inducible genes in the highly drought-tolerant cowpea: cloning of cDNAs and analysis of the expression of the corresponding genes.

Ten cDNAs of genes that were induced by dehydration stress were cloned by differential screening from the highly drought-tolerant legume, cowpea (Vigna unguiculata), a major crop in West Africa. The clones were collectively named CPRD (cowpea clones responsive to dehydration). Northern blot analysis revealed that nine of the CPRD genes were induced by dehydration stress, but the timing of induction of mRNA synthesis varied among the CPRD genes. We analyzed the effects of other environmental stresses on the expression of the CPRD8, CPRD14 and CPRD22 genes, and we found that these genes were strongly induced by high-salinity stress but not by cold or heat stress. Drought-stressed cowpea plants accumulated abscisic acid (ABA) to a level that was 160 times higher than that in unstressed plants. The CPRD8 and CPRD22 genes were induced to a significant extent by the application of exogenous ABA but the CPRD14 gene was not. These results indicate the existence of at least two signal-transduction pathways between the detection of water stress and the expression of CPRD genes in cowpea. Sequence analysis of CPRD8 and CPRD22 cDNAs revealed that they encoded putative proteins that were related to old yellow enzyme and group 2 LEA proteins, respectively. The protein encoded by CPRD14 exhibited sequence homology to dihydroflavonol-4-reductase (DFR) and vestitone reductase (VR). Old yellow enzyme, DFR and VR have not been identified as drought-inducible proteins in other plants, whereas LEA genes have been well characterized as drought-inducible genes. The various gene products might function to protect cells from environmental stress.

Effects of glycine betaine on plant growth and performance of Medicago sativa and Vigna unguiculata under water deficit conditions

Managing water consumption of the crops is one of the strategies which have been adopted locally and worldwide in current trends of sustainable agriculture. In addition to the low level of water resources in UAE because of the rare precipitation, no fresh, free-flowing water, rivers, lakes or streams. The present study was aimed to evaluate the effects of exogenous Glycine Betaine (GB) on Alfalfa (Medicago sativa) and Cowpea (Vigna unguiculata) within different levels of drought stress. A pot experiment was designed on a completely randomized block design (CRBD) with three replicates. Exogenous GB was applied as a foliar spray in three levels (0,100 and 200 ppm) five times with five days intervals. Drought stress starts within the second GB treatment in three levels (24h: 100% well-watered), (48h: 60% water deficit) and (72h: 40% water deficit) depending on the required quantity. Growth characteristics, pigment concentrations, biochemical content and Mineral nutrients levels were measured in response to the treatment variables. Results showed that the GB has a significant increment in Growth parameters, biochemical contents, and Mineral nutrients concentrations. The results of the present investigation suggested that the exogenous application of GB was improved the drought tolerance in Cowpea and has enhanced the Alfalfa performance under drought stress in both concentrations 100 and 200 ppm under drought stress of 60% of irrigations water. In due of comparison of Cowpea and Alfalfa, it’s found from this study that GB has a better effect on the Cowpea under drought stress than Alfalfa.