Glutathione S-Transferase Genes Differently Expressed by Pathogen-Infection in Vitis flexuosa

Glutathione S-transferase (GST) genes from transcripts of Vitis flexuosa leaves infected with Elsinoe ampelina were characterized and analyzed for their expression using primers based on specific regions. Comparison of deduced amino acid sequences from GST transcripts of V. flexuosa showed that the score of the deduced amino acid identity ranged from 43.38% (VfGST26625 and VfGST774) to 6.67% (VfGST13892 and VfGST774). Primary and secondary structure analysis was performed using the ProtParam and Self-Optimized Prediction Method with Alignment software. A phylogenetic tree was constructed from the GST proteins by the neighbor joining method using MEGA 6.0 to investigate the relationship among VfGST, VvGST, and At GST proteins. To evaluate the differential expression pattern of GST genes by real-time polymerase chain reaction (PCR), primers specific to unique regions in each gene were obtained by alignment of the sequences. Real-time PCR revealed that GST genes were expressed differentially in the leaves of V. flexuosa infected with Botrytis cinerea, E. ampelina, and Rhizobium vitis. The expression of VfGST26625 was up-regulated, while that of others were down-regulated among five GSTs in all grapevine leaves inoculated with each pathogen. The results provided herein improve our understanding of defense responses to various pathogen attacks in grapevines.