Drought stress modulates expression of aquaporin gene and photosynthetic efficiency in Pennisetum glaucum (L.) R. Br. genotypes

Abstract Photosynthetic efficiency and availability of water have a close relationship which determines the growth and development of plants. Drought has a remarkable effect on photosynthetic efficiency by affecting the functioning of Photosystem II (PSII). In this study, two drought genotypes of pearl millet were taken and assessed for photosynthetic performance of PSII (electron transport rate (ETR) and maximum yield) under a simulated drought stress condition. Drought stress caused a gradual downregulation in the chlorophyll content in both genotypes. The elevated content of β-carotene was recorded on the 12th day of the experiment. The photo inactivation of PSII was also assessed in both the genotypes. On the basis of an overall comparison, it is evident that the genotype IP14599 has better adapted to drought than the genotype IP14222. Furthermore, the results were confirmed by the analysis of transcript expression level of two aquaporin candidate genes (PIP2;3 and PIP1;5) and it was found that genotype IP14599 was better to maintain homeostasis by increasing in water channeling and movement in response to drought as compared to IP14222. Therefore, it was confirmed that PIP2; 3 and PIP1;5 gene modulate expression of mRNA to provide tolerance against drought in millet plants.