Genome wide analysis of RLK-Pelle-L-LEC family in Rosa chinensis and negative regulation of black spot disease by RcPLLEC45.

Abstract

Protein kinases represent one of the largest protein families in plants and play vital roles in growth, development, and stress responses. In this study, we identified 78 RLK-Pelle-L-LEC (PLLEC) subfamily members within the Rosa chinensis genome. Through comprehensive analyses, including genome-wide identification, collinearity assessment, examination of promoter cis-regulatory elements, and gene expression profiling, we elucidated the structural and functional diversity of the RcPLLEC subfamily. Evolutionary analysis indicated that these 78 RcPLLEC genes are largely conserved, with evidence of tandem duplication events contributing to their expansion. Cis-acting element analysis within promoter regions, combined with gene expression clustering, revealed that most RcPLLEC family members possess light-responsive elements and regulatory motifs associated with environmental stress. Furthermore, infection by the fungal pathogen Marssonina rosae (M. rosae) significantly perturbed the expression of the majority of RcPLLEC genes. Notably, the expression profile of the RcPLLEC45 gene exhibited a distinct bimodal pattern during infection. Utilizing Virus-Induced Gene Silencing (VIGS), we investigated the functional role of RcPLLEC45 during M. rosae infection, specifically monitoring alterations in hormone levels and relevant physiological indicators. Our findings demonstrate that RcPLLEC45 expression negatively regulates defense responses against black spot disease. Moreover, we provide evidence suggesting that RcPLLEC45 expression potentially facilitates jasmonic acid (JA) biosynthesis, modulates catalase activity, and influences hemicellulose synthesis, collectively contributing to the susceptibility of rose to M. rosae infection.