Monitoring the activation of jasmonate biosynthesis genes for selection of chickpea hybrids tolerant to drought stress

Oxylipin family of signals represents one of the mechanisms employed by plants to communicate and respond to wounding, herbivores, and to biotic and abiotic stresses. This family comprises fatty acid hydroperoxides, hydroxy-, keto- or oxo- fatty acids, volatile aldehydes, divinyl ethers and Jasmonic Acid (JA). Most of them are volatile compounds participating in several physiological processes, defence mechanism, stress adaptation and communication with other plants and microorganisms. Studies on the comparison of jasmonates, OPDA, and Abscisic Acid (ABA) content and of gene expression variation in chickpea roots from a drought tolerant and a responsive variety, have confirmed preliminary studies made on drought and salt stress on different chickpea varieties, showing that involvement and up-regulation of specific LOX, AOS and HPL isoforms is required for stress tolerance. In this context, various levels of regulation of jasmonate signaling and JA biosynthesis pathway are discussed, sustained by observations made in roots and nodules of salt stressed chickpea varieties. Finally, an additional level of regulation of JA by epigenetics and microRNAs, with the involvement of ABA and NO responsive elements in promoters of transcription factor genes, is briefly introduced. Here we report about new insights on the role of the differential activation of JA biosynthesis during abiotic stress in roots of varieties differently responding to drought and salt stress, and on the importance of earlier and stronger JA induction as a trait conferring better drought tolerant in legume varieties able to cope with water stress. Real-time PCR may be useful to evaluate the timing and expression levels of specific gene isoforms in tolerant varieties, thus supporting breeding programmes for the identification of hybrids with improved JA synthesis, able to activate oxylipin specific pathways in a sustained and prolonged time course after stress perception.