Genome-wide identification and characterization of the Trihelix transcription factor family and functional analysis of VaTrihelix23 under low temperatures stress in Vitis amurensis.

BACKGROUND: Trihelix is a class of transcription factors unique to plants that play a major role in abiotic and biotic stress responses, seed isolate development, floral organ morphogenesis, and plant photomorphogenesis. Nevertheless, the Trihelix transcription factor family in Vitis amurensis Rupr. (V. amurensis) has not been systematically characterized. RESULTS: In this study, 31 VaTrihelix genes were identified in V. amurensis, unevenly distributed across 16 chromosomes with phenomena of clustering. These genes encode hydrophilic proteins (158-858 amino acids) rich in α-helices, predominantly localized in the nucleus. Proteins sharing similar conserved motifs are grouped together phylogenetically. Cis-acting element analysis revealed numerous cis-acting elements associated with environmental and hormonal responses. Phylogenetic analysis of Trihelix members from V. amurensis, Vitis vinifera L. (V. vinifera), V. amurensis, Oryza sativa L. (O. sativa), and Arabidopsis thaliana (L.) Heynh. (A. thaliana) were divided them into four subclades. Interspecies collinearity indicated greater homology between V. amurensis and dicots (V. vinifera and A. thaliana) than with the monocot O. sativa. Purifying selection acted on VaTrihelix genes during evolution. Predicted protein interactions were observed among some family members. RT-PCR analysis showed that VaTrihelix15, VaTrihelix23, and VaTrihelix30 were upregulated under all four low-temperature stress conditions. the expression levels of VaTrihelix5, VaTrihelix6, VaTrihelix7, VaTrihelix9, VaTrihelix15, VaTrihelix19, VaTrihelix20, VaTrihelix25, VaTrihelix27, VaTrihelix28, VaTrihelix29, VaTrihelix30, and VaTrihelix31 under -5 °C and -10℃ stress showed significant differences compared to the control (A). CONCLUSIONS: This study preliminarily characterized the fundamental bioinformatic information of VaTrihelix transcription factors and revealed the potential roles of the Trihelix family transcription factors under low-temperature stress. The findings provided a theoretical foundation and candidate genes for future cold resistance breeding in grapevine.