Identification of MAPK Genes in Phaseolus vulgaris and Analysis of Their Expression Patterns in Response to Anthracnose

Abstract

The oil bean is a high-quality, economically valuable variety of kidney bean (Phaseolus vulgaris L.) that is widely cultivated in Northeast China. However, the prevalence of anthracnose, caused by a combination of factors, including continuous cropping over many years, has led to significant declines in both yield and quality. The mitogen-activated protein kinase (MAPK) cascade is a highly conserved plant cell signaling pathway that plays a pivotal role in plant growth and development, as well as responses to biotic stress. However, its role in the response of P. vulgaris to anthracnose infection has not previously been reported. We identified and characterized thirteen MAPK genes (PvMAPK01–PvMAPK13) in the P. vulgaris genome. These genes were found on eight of the eleven chromosomes of P. vulgaris, and phylogenetic analyses classified them into four previously established subgroups (A–D). Analysis of the cis-acting elements in their promoter regions revealed the presence of multiple elements associated with light, hormone regulation, stress responses, and growth and development. An analysis of intraspecific collinearity revealed that whole-genome and/or segmental duplication, rather than tandem duplication, has been the primary driver of PvMAPK family expansion in P. vulgaris. Transcriptome data revealed that the PvMAPKs differed in their tissue-specific expression patterns, with PvMAPK05 showing particularly high expression in stems and stem tips and PvMAPK07 and PvMAPK11 showing relatively low expression across all tissues. In general, expression of the PvMAPKs was higher in stems, stem tips, and pods than in other tissues and organs, suggesting that they may be particularly important for regulating stem and pod development. Analysis of the expression of PvMAPKs in field-grown plants infected or uninfected with anthracnose revealed that the relative expression levels of PvMAPK05, PvMAPK07, PvMAPK09, and PvMAPK11 exhibited particularly significant changes in response to anthracnose infection across different varieties, suggesting their potential involvement in the anthracnose response of Phaseolus vulgaris. This study reports the fundamental characteristics of the thirteen MAPK genes in P. vulgaris, documents their expression patterns in diverse tissues, and offers preliminary insights into their responses to anthracnose infection, establishing a foundation for subsequent functional validation.