Genome-Wide Identification and Characterization of the Trihelix Transcription Factor Family in Pinus massoniana and Gene Expression Patterns Analysis

<i>Pinus massoniana</i> Lamb. possesses considerable ecological and economic value. However, the rapid proliferation of pine wilt disease poses a significant threat to the growth and development of coniferous plants. Transcription factors play a crucial role in enabling plants to respond to external environmental stresses. The trihelix transcription factor (TTF) family, named after its unique trihelical domain (helix-loop-helix-loop-helix) and also referred to as the GT family, plays crucial roles in plant morphogenesis and in responses to biotic and abiotic stresses. In this study, we identified 56 <i>PmGTs</i> from the <i>P. massoniana</i> genome and analyzed their expression profiles in response to pine wood nematode (PWN) infection. Eight significantly differentially expressed <i>PmGTs</i> at various stages were selected as candidate genes for PWN resistance. Promoter analysis and qRT-PCR revealed that these genes respond to multiple treatments, including methyl jasmonate (MeJA), indole-3-acetic acid (IAA), gibberellic acid (GA3), salicylic acid (SA), and abscisic acid (ABA). Subcellular localization analysis revealed that the proteins are localized in the nucleus. Additionally, seven <i>PmGTs</i> exhibit transcriptional activity. This study provides a foundational understanding of the role of <i>PmGTs</i> in stress response in <i>P. massoniana</i>.