Genome-wide analysis of the SMXL gene family in common bean and identification of karrikin-responsive PvSMXL2 as a negative regulator of PEG-induced drought stress

•Nine orthologues of SMXL genes in common bean were identified.•The basic molecular properties of PvSMXLs were characterized, and cis-elements in their promoters were predicted.•The expression patterns of PvSMXL genes under PEG, Cu, and KAR1 treatments were analyzed.•PvSMXL2, which responds to PEG, Cu and KAR1 treatments, negatively regulates drought tolerance.