OsDUF1223 negatively regulates seedling drought tolerance and modulates nitrate-dependent root growth in rice.

Rice (Oryza sativa L.) is a major staple food crop worldwide. Drought stress induced by extreme weather severely limits its growth and yield. Proteins containing domains of unknown function (DUF) play important roles in plant stress responses, but their regulatory mechanisms remain largely unclear. In this study, we demonstrate that the plasma membrane-localized protein OsDUF1223 functions as a negative regulator of drought tolerance in rice seedlings. Under drought stress, OsDUF1223-overexpressing lines exhibited lower survival rates, higher water loss rates, and reduced antioxidant enzyme activities and osmolyte accumulation. Transcriptomic and physiological analyses revealed that OsDUF1223 modulates drought responses through ABA signaling and nitrogen response pathways. Collectively, this study elucidates that OsDUF1223 regulates drought tolerance at the seedling stage in rice through functional association with the ABA and nitrogen signaling pathways, thereby providing a candidate gene resource for the genetic improvement of drought tolerance in rice.