Identification and characterization of salt stress-responsive NHX gene family in chickpea

Chickpea (Cicer arietinum L.) is an important legume crop, primarily grown in the arid and semi-arid regions. It is a valuable protein source and rich in minerals, especially calcium and phosphorus. Salinity stress adversely affects chickpea germination, vegetative growth, and reproductive activities. The Na+/H+ exchanger (NHX), a gene family of membrane transporters, is well recognized for inducing salt tolerance in plants. The NHXs assist in maintaining ion and pH homeostasis in cells by exchanging K+ or Na+ for H+. This study was designed to identify and characterize the NHX genes for salt stress responsiveness in chickpea. Eight NHX genes were identified in chickpea. The phylogenetic analysis represented the evolutionary relationship of Cicer arietinum NHXs (CarNHXs) with Glycine max, Medicago truncatula, Lotus japonicus, Phaseolus vulgaris, Lens culinaris, Vigna unguiculata, and Oryza sativa. The in-silico gene expression analysis indicated high expression of CarNHX3 (Ca_19073) and CarNHX7 (Ca_02050) under salt stress. The qRT-PCR further validated that the expression of CarNHX3 and CarNHX7 increased when plants were exposed to salt stress. This study provides a way forward to plan functional research to exploit CarNHX genes to enhance salt-tolerance in chickpea.