Target cleavage mapping and tissue-specific expression analysis of PGPR responsive miR166 under abiotic stress in chickpea ( Cicer arietinum L.)

Legumes are an indispensable food after cereals with extensive production across the world. Legume production is imposed with limitations and has been augmented by various environmental stresses. The symbiotic relations between legumes and rhizobacteria have been an intriguing topic of research in view of their roles in plant growth, development and various stress responses. Recent advances in gene networks involving a plethora of evolutionarily conserved miRNAs have been investigated pertaining to their roles in plant stress responses. The interaction between plant growth-promoting rhizobacteria (PGPR) strain Pseudomonas putida (RA), MTCC5279 and abiotic stress-responsive miRNAs have previously been studied with roles in abiotic stress mitigation by modulating stress-responsive miRNAs and their target genes. The present study is an investigation involving the role of RA-responsive miR166 for drought mitigation in desi chickpea genotype. Drought-stressed chickpea plants when inoculated with RA, the inverse correlation in expression patterns were noticed in miR166 and its validated target, ATHB15 . miR166-directed cleavage of ATHB15 has been carried out in drought-treated plantlets upon RA inoculation using 5´RLM-RACE analysis. Tissue-specific expression patterns in 15 days old chickpea seedlings including leaves, shoot and roots when exposed to salinity, drought and abscisic acid at different time points indicating the role of miR166 in different abiotic stress responses. In view of the results, validation and functional characterization of such interactions involving stress-responsive miRNAs along with microbial applications in stress management could be an important method for crop improvement.