Transcriptomic analysis of photosynthesis-related genes regulated by alternate wetting and drying irrigation in flag leaves of rice

Alternate wetting and drying (AWD) irrigation has been widely used to replace continuous flooding (CF), which does not result in yield loss while improving water productivity. However, it is still unexplored as to how this agricultural practice would affect gene expression to control plant physiology. In this study, we found that photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), chlorophyll (Chl) content, and leaf water potential (Lwp) significantly decreased while abscisic acid (ABA) content and water use efficiency (WUE) increased when soil water potential reached to −15 kPa in the AWD irrigation regime. We then analyzed the differences between AWD and CF irrigation practices in transcriptomic profiles for flag leaves. Genes were found to be differentially expressed in photosynthesis related pathways namely, Chl biosynthesis, photosynthesis-antenna proteins pathway, photosynthesis process, and ABA signal transduction pathway. The study provides important information on the morphological adaptations observed in the flag leaves in response to AWD irrigation, which will act as a basic framework to conduct molecular studies for improving rice cultivation.