Expression profiling of selected photosynthetic genes from nine halophytic C4 grasses thriving in extreme Kutch desert of India

The Kutch desert of India is a unique ecosystem where both salinity and drought occur together. The halophytic grasses should have the adaptability to survive in such harsh and diverse temperature conditions. In the present study, we selected nine such C4 fodder grass species from the saline desert of Kutch, India. The cpDNA form these grasses was isolated and the complete plastome sequences were deposited in the NCBI database. A comparative analysis of these plastomes was carried out to check the expression profiles of three genes of IR region (ndhB, ndhF and rps15) and 6 photosynthetic genes (rbcL, psbA, psaA, psaB, petA and petB). Further, two species (Cenchrus ciliaris and Cymbopogon citratus) occurring in both saline and non-saline environment were also compared with model C3 grass Triticum aestivum. RT-PCR (real time) with appropriate primers for each gene was performed. It was observed that saline habitat hindered the expression profile of the studied genes. Gene stability analysis by RefFinder server which integrates four different methods i.e. RefFinder, geNorm, BestKeeper and NormFinder revealed overall the highest stability for rbcL while the lowest for psaA gene. Gene expression of selected photosynthetic genes in the C3 plant is overall higher than all other selected C4 grasses may be because of different abiotic stresses of the Kutch area. This result suggests that remaining green in such harsh environmental conditions is at the cost of photosynthesis.