Genome-wide characterization of pyrabactin resistance 1-like (PYL) family genes revealed AhPYL6 confer the resistance to Ralstonia solanacearum in peanut

Bacterial wilt (BW) caused by Ralstonia solanacearum severely impacts the yield and quality of peanut (Arachis hypogaea L.), a globally cultivated industrial crop. Despite the abscisic acid (ABA) signaling pathway have been identified as key factors in peanut resistance to BW, the molecular mechanism remains unclear. Through systematic identification, it was discovered that the peanut genome contains 18 ABA receptor pyrabactin resistance 1-like (PYL) family genes, which show conservation with other plant species. Among these PYL genes in peanut (referred to as AhPYL), AhPYL6 and AhPYL16 showed significant up-regulation in response to salicylic acid, jasmonic acid, ABA treatments, and R. solanacearum infection. Subsequently, the full-length AhPYL6 was cloned and functionally characterized. The fusion protein AhPYL6-YFP was predominantly expressed in the cytoplasm and nucleus of tobacco leaves, and overexpression of AhPYL6 notably enhanced resistance against R. solanacearum. Expression analysis revealed that the expression levels defense -related genes including NbNPR1, NbPR2, NbPR3, NbHRS203, NbEFE26, and NbNDR1 were significantly up-regulated by the overexpression of AhPYL6, which suggested that AhPYL6 confers the resistance to R. solanacearum through promoting expression of defense -related genes. These findings highlight the potential roles of PYL ABA receptors in the plant defense response to bacterial pathogens.