[Fuctions of the aspartic proteasegene AhAP12 in peanut nodulation]

Peanut (Arachis hypogaea L.) is one of China's important oilseed and economic crops, and its symbiotic nitrogen fixation system formed with rhizobia has significant agricultural and ecological value. The aspartic protease family plays a crucial role in plant stress resistance and hormone signal transduction, while its function in leguminous plants for nodular nitrogen fixation remains unclear. This study identified a specifically expressed aspartic protease family gene, AhAP12, which rapidly responded to rhizobial infection in peanut nodules through bioinformatics analysis. Subcellular localization analysis revealed that AhAP12 was localized to both the nucleus and cell membrane. Moreover, overexpression of AhAP12 in peanut hairy roots significantly increased nodule formation, while silencing AhAP12 markedly reduced nodulation, which indicated that AhAP12 positively regulated peanut nodulation. Further expression analysis revealed that AhAP12 might influence the nodulation process by regulating the expression of multiple key nodulation-related genes, including AhNIN and AhHK. This study is the first to elucidate the role of AhAP12 in symbiotic nitrogen fixation in legumes, providing new theoretical insights into the molecular mechanisms of nodulation and nitrogen fixation. Additionally, it offers valuable genetic resources for breeding new peanut varieties with enhanced nodulation efficiency and improved nitrogen utilization.