Characterization of the m6A Regulatory Gene Family in Phaseolus vulgaris L. and Functional Analysis of PvMTA in Response to BCMV Infection

Common bean (<i>Phaseolus vulgaris</i> L.) is known for its high protein, dietary fiber, and various trace element contents, making it a widely grown leguminous crop globally. The bean common mosaic virus (BCMV) poses a significant threat to leguminous crop production, causing substantial yield reductions when common beans are infected. Widely occurring in mRNA, the m⁶A modification is vital for maintaining mRNA stability, facilitating splicing, enabling nuclear export, supporting polyadenylation, and initiating translation. Recent studies have identified the m⁶A regulatory gene family in various plant species, and its ability to regulate plant virus infection has been confirmed. There is currently insufficient information regarding the m⁶A regulatory gene family in beans and how it responds to BCMV infection. Consequently, we carried out a genome-wide characterization of the m⁶A regulatory gene family in common bean, which led to the identification of 31 potential regulatory gene members associated with m⁶A. According to evolutionary analysis, the increase in the bean m⁶A regulatory gene family appears to be linked to either whole-genome duplication or segmental duplication events. Subsequent investigations into the expression levels of these genes throughout different phases of BCMV infection showed that all candidate genes responded to the infection with various changes in expression. Moreover, we characterized the methyltransferase activity of PvMTA and validated the interactive relationship between mRNA adenosine methyltransferase A (MTA) and mRNA adenosine methyltransferase B (MTB) in common beans. Through overexpressing and silencing <i>PvMTA</i>, we further ascertained that this particular gene has a detrimental impact on the regulation of BCMV infection. This research provides fresh perspectives on the molecular processes that govern the interaction between the common bean and BCMV and aids progress in molecular bean breeding.