Genome-Wide Identification and Expression Analysis of the Trihelix Gene Family in Common Bean (Phaseolus vulgaris L.) Under Salt and Drought Stress

Abstract

Triple-helix transcription factors (GT factors) play a pivotal role in plant abiotic stress responses and growth and development. Named for their specific binding affinity to GT factors, they are clustered into five subgroups: GT-1, GT-2, GT-γ, SIP1 and SH4. In Phaseolus vulgaris, 43 GT family members have been identified through reference genome analysis. PvGT members exhibit uneven genomic distribution, and members within the same subgroup share similar gene structures and motifs. Cis-acting element analysis indicates the involvement of PvGTs in hormonal signalling and abiotic stress regulation. Collinearity analysis revealed four pairs of homologous PvGTs. To investigate their expression patterns, nine PvGTs with high expression levels were selected for quantitative real-time PCR (qRT-PCR) analysis. Among these, PvGT02, PvGT28, PvGT30 and PvGT34 were significantly upregulated under salt and drought stress. Functional characterisation demonstrated that PvGT02 significantly enhanced yeast tolerance to salt and drought stresses. These findings collectively contribute to our understanding of the PvGT family evolution in common bean, providing a foundation for further exploration. Additionally, PvGT02 emerges as a potential candidate gene for breeding salt and drought tolerance.