Abstract
Abiotic stresses significantly impact plant growth and productivity. To overcome these challenges, plants employ photosynthetic acclimation mechanisms, enabling them to sustain photosynthetic efficiency under adverse conditions. The OsFLN2 gene has been identified as a key player in chloroplast development and response to heat and salinity stress. However, the physiological effects of OsFLN2 gene knockout and its impact on drought tolerance remain elusive. In this study, we explored the function of OsFLN2 in rice plants under water deficit conditions using a non-transgenic CRISPR knockout mutant. Our findings demonstrate that Osfln2 mutant plants exhibit higher sensitivity to water deficit, characterized by reduced photosynthetic activity and reduced transcriptional responsiveness of plastid genes, such as RbcL and PsaA. As a result, these plants display compromised carboxylation efficiency and reduced leaf water use efficiency at the maximum water deficit. Concluding, our results demonstrate the role of OsFLN2 on physiological acclimation of rice plants under water-limiting conditions.