Cloning and expression under drought of cDNAs coding for two PI-PLCs in cowpea leaves

Two cDNAs coding for putative phosphoinositide-specific phospholipase C (PI -PLC, EC 3.1.4.3) from cowpea leaves (Vigna unguiculata L. Walp) were clone d and characterized. These cDNAs designated VuPLC1 and VuPLC2 belong to the delta-type PI-PLCs and revealed deduced amino acid homology of 66 %. North ern blot analysis of mRNA from leaves of two V. unguiculata cultivars diffe ring in their sensitivity to drought (drought-sensitive, 1183, and drought- tolerant, EPACE-1) showed that VuPLC1 transcript level decreased under prog ressive water stress in the two cultivars, whereas VuPLC2 gene expression i s stimulated up to -1.5 MPa only in the tolerant cultivar. These results su ggest different physiological roles for the two genes and demonstrate diffe rential behaviour of one PI-PLC gene expression in two cultivars belonging to the same species. (C) 2001 Editions scientifiques et medicales Elsevier SAS.