Proteomic variation in Vitis amurensis and V. vinifera buds during cold acclimation

Abstract Amur grape (Vitis amurensis) is a wild grape species with excellent freezing tolerance compared with the widely cultivated common grapevine (V. vinifera). Here, we investigated the effect of cold acclimation (CA) on the proteomes of V. amurensis (cv. Zuoshan-1) and V. vinifera (cv. Jingzaojing) buds to explore the cold-tolerance mechanisms used by these species. The buds were collected in late fall (October) and early winter (December) and subjected to an iTRAQ-based proteomic analysis. A total of 472 and 713 differentially abundant proteins (DAPs) were identified between the two time points in V. amurensis and V. vinifera, respectively. The two species shared 235 DAPs, which were mainly involved in the protein chaperone and metabolic pathways, particularly carbohydrate metabolism. These DAPs represent the general responses to CA in Vitis species. V. amurensis contained less unique DAPs (237) than V. vinifera (478). A functional category analysis indicated that the phenylpropanoid biosynthesis pathway was enriched in V. amurensis. Among the DAPs identified in this pathway, seven upregulated and three downregulated DAPs were present in V. amurensis, while three upregulated and 20 downregulated DAPs were present in V. vinifera. Contrasting patterns were observed between the two species for phenylalanine ammonia-lyase, cinnamoyl-CoA reductase 1, and shikimate O-hydroxycinnamoyl transferase, which accumulated in V. amurensis but decreased in V. vinifera. The qRT-PCR results indicated that the transcriptional changes of 12 genes encoding selected DAPs were all consistent with the changes observed at the protein level. Our work provides new insights into the mechanisms by which cold hardiness is achieved in V. amurensis buds.