LRR Receptor-like Protein in Rapeseed Confers Resistance to Sclerotinia sclerotiorum Infection via a Conserved SsNEP2 Peptide

<i>Brassica napus</i> is one of the most extensively cultivated oilseed crops in China, but its yield is significantly impacted by stem rot caused by <i>Sclerotinia sclerotiorum</i>. Receptor-like proteins (RLPs) and receptor-like kinases (RLKs) play essential roles in plant-pathogen interactions; however, their regulatory mechanisms remain largely unknown in <i>B. napus</i>. In this study, we investigated the function of the leucine-rich repeat receptor-like protein <i>Bna</i>RLP-G13-1 in <i>Brassica napus</i> immunity. Previous observations indicated that <i>B. napus</i> plants expressing <i>Bna</i>RLP-G13-1 exhibited enhanced resistance to <i>Sclerotinia sclerotiorum</i>. We hypothesized that <i>Bna</i>RLP-G13-1 mediates pathogen recognition and immune signaling. To test this, we employed mitogen-activated protein kinase (MAPK) activity assays, transgenic overexpression analyses, and pathogen infection assays. Our results demonstrated that <i>Bna</i>RLP-G13-1 recognizes the conserved necrosis- and ethylene-inducing peptide <i>Ss</i>nlp24<i>_SsNEP2</i> derived from <i>S. sclerotiorum</i>, triggering MAPK cascades and subsequent immune responses. Furthermore, protein interaction studies revealed that <i>Bna</i>RLP-G13-1 physically interacts with the receptor-like kinase <i>Bna</i>SOBIR1, which is essential for full antifungal defense activation. These results elucidate the molecular basis of <i>BnaRLP-G13-1</i>-mediated immunity, providing insights into improving disease resistance in oilseed crops.