Identification of symbiotic nitrogen fixation‐modulating factors in alfalfa and mechanism elucidation of MsHHO3

Symbiotic nitrogen fixation (SNF), a unique nitrogen acquisition mechanism formed through the interaction between leguminous plants and rhizobia, plays a critical role in reducing dependence on chemical fertilizers. However, in alfalfa (Medicago sativa L.), the mechanisms underlying nitrate-responsive SNF remain poorly understood. In this study, we elucidate a nitrate-responsive regulatory network governing SNF in alfalfa and identify MsHHO3 as a key regulator. qRT-PCR analysis revealed that MsH