Isolation and characterization of a dehydrin gene from Cicer pinnatifidum, a drought-resistant wild relative of chickpea

Chickpea is an important legume crop of the tropics and subtropics. As it is cultivated mostly during the dry season, drought is the major cause of poor chickpea yields. A wild relative of chickpea, Cicer pinnatifidum, is more tolerant than chickpea itself to various abiotic stresses, including drought. A cDNA clone encoding a dehydrin gene, cpdhn1, was isolated from a cDNA bank prepared from ripening seeds of C. pinnatifidum. Dehydrins are proteins which accumulate in seeds during late embryogenesis and also during stress brought about by drought and other abiotic factors in many plants. The polypeptide deduced to correspond to this gene, cpdhn1, consists of 195 amino acid residues with a molecular mass of 20.4 kDa. The polypeptide is a Y2K dehydrin exhibiting two conserved 'Y'-segments in the amino-terminal region and one conserved 'K'-segment close to the carboxy terminus. Northern blot analyses showed that cpdhn1 expression was induced not only during seed development, but also in leaves in response to drought, chilling and salinity and also to treatment with ABA or methyl jasmonate. The induction of cpdhn1 expression by methyl jasmonate and ABA indicates that the gene may also be involved in the response to biotic stress. The CpDHN1 protein may thus improve the tolerance of chickpea to a variety of environmental stresses, both abiotic and biotic.