Novel drought-inducible genes in the highly drought-tolerant cowpea [Vigna unguiculata]: Cloning of cDNAs and analysis of the expression of the corresponding genes

• Published in: Plant and cell physiology Vol. 37; no. 8; pp. 1073 - 1082
• Main Authors: Iuchi, S. (Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki), Shinozaki, K.Y, Urao, T, Terao, T, Shinozaki, K
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.12.1996
• Subjects: Abscisic acid; Abscisic Acid - metabolism; Agronomy. Soil science and plant productions; Amino Acid Sequence; amino acid sequences; ANALYTICAL METHODS; Base Sequence; Biological and medical sciences; Blotting, Northern; CLONACION MOLECULAR; CLONAGE MOLECULAIRE; clones; cloning; Cloning, Molecular; complementary DNA; COVARIANCE GENETIQUE; COVARIANZA GENETICA; Cowpea (Vigna unguiculata); dehydration; DNA, Complementary; Drought; DROUGHT RESISTANCE; drought tolerance; Economic plant physiology; EXPRESION GENICA; EXPRESSION DES GENES; Fundamental and applied biological sciences. Psychology; genbank/d83970; genbank/d83971; genbank/d83972; GENE EXPRESSION; genes; Genes, Plant; GENETIC COVARIANCE; GENETIC POLYMORPHISM; genetic variation; Heat-Shock Proteins - genetics; MOLECULAR CLONING; Molecular Sequence Data; nucleotide sequences; Pisum sativum - genetics; Plant physiology and development; Plant Proteins; POLIMORFISMO GENETICO; POLYMORPHISME GENETIQUE; RESISTANCE A LA SECHERESSE; RESISTENCIA A LA SEQUIA; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Stress response; TECHNIQUE ANALYTIQUE; TECNICAS ANALITICAS; VIGNA UNGUICULATA; Water; Water and solutes. Absorption, translocation and permeability; Water relations, transpiration, stomata; Nucleotide sequence; Enzyme; Induction; Water deficit; Vigna unguiculata; Homology; Dihydrokaempferol 4-reductase; Gene expression; Stress; Salinity; Response; Grain legume; Signal transduction; Leguminosae; Complementary DNA; Dicotyledones; Angiospermae; Abscisic acid; Spermatophyta; Oxidoreductases; Biological accumulation; Aminoacid sequence
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/oxfordjournals.pcp.a029056

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.