Long-term drought resistance in rice (Oryza sativa L.) during leaf senescence: a photosynthetic view

Drought is one of the major abiotic stress that limits crops yield. Here we investigated photosynthetic performance in flag leaves of a hybrid rice (Oryza sativa. L) LYPJ exposed to prolonged drought stress during leaf senescence. Our results highlighted an architecture remodeling of thylakoid membrane proteins characterizing by amplified PSI-LHCII and PSII dimers supercomplexes and LHCII assemblies played crucial role in drought resistance. Coordination of PSII and LHCII protein phosphorylation, thermal dissipation, and CEF around PSI sustained photo-equilibrium when LEF was suppressed by decreased Cytb6f complex. CO2 limitation resulted in degradation of Rubisco content and loss of Rubisco activity, but up-regulated the enzymes responsible for C4 photosynthesis pathway. It was collectively pointed to that redox poise was a pivotal and ATP/NADPH ratio was probably a linker of light reaction, CO2 assimilation and other metabolism pathways. In general, our results provided additional insights into the role of thylakoid membrane plasticity in long-term ambient acclimation and complex coordination of drought responses in rice LYPJ during the senescence stage.