<scp> <i>AhBWR15</i> </scp> , A Novel <scp>RLK</scp> Gene, Confers Resistance to <scp> <i>Ralstonia solanacearum</i> </scp> in Peanut

Bacterial wilt (BW), a severe soil-borne disease caused by Ralstonia solanacearum, significantly impedes global peanut production. Despite its impact, the mechanisms underlying BW resistance in peanut remain unclear. Herein, we selected the highly resistant variety Nongdahua108 (H108) and the susceptible variety Nongdahua107 (H107) to develop a genetically segregating population. Bulked segregant analysis sequencing (BSA-seq) of the F₂ population (n = 432) revealed a novel major quantitative trait locus (QTL) qBWR15, located within a 5.9-Mb region on Chromosome 15 (B05). Subsequently, 25 new molecular markers were developed within this region, allowing for the fine mapping of qBWR15 to a 668-kb region containing four genes with non-synonymous mutations. Notably, one of these genes, a leucine-rich repeat receptor-like kinase (LRR-RLK) designated as AhBWR15, exhibits a non-synonymous G > A mutation in the first exon. This mutation results in alterations to the encoded amino acid and the three-dimensional structure of the protein. The 238 natural germplasms analysis also identified this novel mutation occurring exclusively in the peanut variety H108. AhBWR15 is localised on the plasma membrane and is responsive to R. solanacearum infection and phytohormone inductions. Overexpression of the LRR-RLK gene AhBWR15 can significantly enhance resistance to BW by activating abscisic acid (ABA)-signalling pathways. Our research provides valuable insights into a novel LRR-RLK-mediated disease resistance pathway, which has significant implications for enhancing peanut resistance to BW.