DROUGHT AFFECTS AQUAPORINS GENE EXPRESSION IN IMPORTANT PULSE LEGUME CHICKPEA (CICER ARIETINUM L.)

Aquaporins (AQPs) mediate cross membrane transport of water and other solutes in plants. AQPs also enhance plant performance under environmental stresses including water shortage. Chickpea (Cicer arietinum L.) is the most important pulse legume for the people of semi-arid tropics. To understand the evolutionary relationships and role of AQPs in drought tolerance in chickpea, the current study involves an evolutionary analysis coupled with expression analysis and promoter analysis of selected AQPs. A total of 503 non-redundant AQP genes have been studied in 11 plant species including mosses (Physcomitrella patens), monocots (Oryza sativa and Zea mays) and dicots (Solanum lycopersicum, Populus trichocarpa, Gossypium hirsutum, Glycine max, Arabidopsis thaliana, Brassica rapa, Solanum tubrosum and Cicer arietinum). Phylogenetic analysis demonstrated a clear divergence of AQP subfamilies as paralogous groups and possible evolutionary direction of AQP subfamilies. Semi-quantitative RT-PCR analysis depicted involvement of PIP2; 2 and NIP6; 3 in increasing plant drought stress tolerance and of SIP1; 1 and PIP2; 3 with a contrary role. In silica promoter analysis identified a 49 bp conserved motif among six AQPs and several abiotic stresses related cis-elements. The present study is a very first step in deciphering AQPs role in drought stress tolerance with a special perspective from evolutionary relationships and gene expression regulation.