Expression Analysis of Trihelix Transcription Factor Family in Strawberries and Functional Characterization of FvTrihelix6

Abstract

The Trihelix is a plant-specific transcription factor family and has critical roles in plant growth and development and stress resistance. There is less information about Trihelix transcription factor genes and their potential functions in strawberries (Fragaria vesca). In the present study, we performed a detailed bioinformatics analysis of the Trihelix family in strawberries including physicochemical properties, chromosomal location, exon–intron distribution, domain arrangement, and subcellular localization. Thirty Trihelix family members were identified and divided into five subfamilies. The expression of FvTrihelix genes in different tissues/organs, i.e., root, stolon, leaf, flower, and fruit, was measured in strawberries after infection with Colletotrichum. gloeosporioides and foliar applications of salicylic acid (SA) and jasmonic acid (JA). Most of the genes showed differential expression responses following C. gloeosporioides infection and hormone treatments (SA and JA), suggesting critical roles in disease resistance and hormonal signaling pathways. As anticipated, the ectopic expression of FvTrihelix6 in Arabidopsis thaliana increased resistance against Colletotrichum. higginsianum infection. FvTrihelix6 protein was localized in the nucleus. We surmise that FvTrihelix6 enhances resistance against pathogens through the SA and JA signaling pathways. This study provides novel insights into the strawberry Trihelix transcription factor genes and new candidates for disease-resistance breeding of strawberries.