Genome-Wide Identification and Characterization of the bHLH Transcription Factor Family in Pepper (Capsicum annuum L.)

Plant basic helix–loop–helix (bHLH) transcription factors are involved in the regulation of various biological processes in plant growth, development, and stress response. However, members of this important transcription factor family have not been systematically identified and analyzed in pepper (Capsicum annuum L.). In this study, we identified 122 CabHLH genes in the pepper genome and renamed them based on their chromosomal locations. CabHLHs were divided into 21 subfamilies according to their phylogenetic relationships, and genes from the same subfamily had similar motif compositions and gene structures. Sixteen pairs of tandem and segmental duplicated genes were detected in the CabHLH family. Cis-elements identification and expression analysis of the CabHLHs revealed that they may be involved in plant development and stress responses. This study is the first comprehensive analysis of the CabHLH genes and will serve as a reference for further characterization of their molecular functions.