Genome-wide exploration and validation of root specific miRNAs contributing towards water conservation in pearl millet. Cenchrus americanus cultivar:ICMR 1122 and ICMR 1152

Pearl millet [Pennisetum glaucum (L.) R. Br.] is an important crop of the arid and semi-arid regions of the world. Capable to grow in harsh and marginal environments with the highest degree of tolerance to drought and heat stresses among cereals. Diverse germplasm of pearl millet shows significant phenotypic variation in response to abiotic stresses. This characteristic feature makes pearl millet a unique model among other cereals to study the mechanisms responsible for mitigating divers abiotic stress. Present study, focused on identifying the physiological response of two pearl millet high resolution cross (HRC) genotypes i.e. Vapour pressure deficit (VPD) insensitive genotype (ICMR 1122) and VPD sensitive genotype (ICMR 1152), in response to low and high VPD. ICMR 1152 was found to be to lower transpiration rate (Tr) under high VPD conditions as it showed higher transpiration efficiency and lower root exudation as compared to ICMR 1122. Further, low and high VPD condition and genotype specific Pg-miRs were identified by deep sequencing analysis. A total of 94, 23 known Pg-miRs are 53, 5 novel miRNAs were identified for ICMR 1152 and 1122 genotypes respectively. The Pg-miR165, 168, 170, and 319 family exhibited significant differential expression under low and high VPD conditions in both genotypes. Pg-miRs specific to adventitious roots development and various stress response has been deciphered. Suitable targets for each Pg-miRs were identified and validated expression of top targets in both genotypes responsible for stress. This study shed light upon the role of miRNAs in regulation of drought tolerance in pearl millet.