Abstract: Rapeseed (Brassica napus L.) exhibits high-sulfur requirements to achieve optimal growth, development, and pathogen resistance. Despite the importance of sulfur, the mechanisms regulating its metabolism and disease resistance are not fully understood. In this study, we found that the zinc finger transcription factors BnaSTOP2s play a pivotal role in sulfur metabolism and Sclerotinia sclerotiorum resistance. Our findings indicate that BnaSTOP2s are involved in sulfur metabolism, as evidenced by extensive protein interaction screening. BnaSTOP2s knockout reduced the content of essential sulfur-containing metabolites, including glucosinolate and glutathione, which is consistent with the significantly lowered transcriptional levels of BnaMYB28s and BnaGTR2s, key factors involved in glucosinolate synthesis and transportation, respectively. Comprehensive RNA-seq analysis revealed the substantial effect of BnaSTOP2s on sulfur metabolism from roots to siliques, which serve as pivotal sources and sinks for sulfur metabolism, respectively. Furthermore, we found that leaf lesion size significantly decreased and increased in the BnaSTOP2-OE and Bnastop2 mutants, respectively, compared with the wild-type during S. sclerotiorum infection, suggesting a vital role of BnaSTOP2s in plant defense response. In conclusion, BnaSTOP2s act as global regulators of sulfur metabolism and confer resistance to S. sclerotiorum infection in B. napus. Thus, they have potential implications for improving crop resilience.

Key words: BnaSTOP2, Brassica napus, CRISPR/Cas9, glucosinolate, Sclerotinia sclerotiorum, sulfur metabolism