A putative NF-Y complex interacting with ERD15 may positively regulate the expression of a peroxidase gene in response to stress in rapeseed (Brassica napus L.)

Drought stress is one of the major constraints on crop productivity, including rapeseed (Brassica napus L.). Nuclear factors Y (NF-Ys) are important transcription factors involved in plant responses to drought and other stresses. However, the underlying molecular mechanisms remain unclear in rapeseed. By silencing BnaNF-YA9 in rapeseed and transforming BnaNF-YA9 into the Arabidopsis mutant Atnf-ya5, we demonstrated that BnaNF-YA9 plays a positive role in drought resistance. To explore its regulatory mechanism, we performed protein-protein interaction analyses using various approaches. Our study revealed complex interactions among BnaNF-YA9, BnaNF-YB2, BnaNF-YC4, and EARLY RESPONSIVE TO DEHYDRATION 15 (ERD15), suggesting that these proteins form a multimember complex. We also showed that BnaNF-YA9 binds to the CCAAT element in the promoter of a BnaPRX gene, which encodes a peroxidase. Interestingly, overexpression of BnaNF-YC4 or BnaERD15 in Arabidopsis increased sensitivity to salt stress, drought, and abscisic acid. Our results support an NF-Y/ERD15/PRX cascade and suggest a complex regulatory network in rapeseed that may be important in maintaining ROS homeostasis during abiotic stress responses. Our findings provide insights into potential targets for improving drought resilience in crops.