Transient expression assays in grapevine: a step towards genetic improvement

Abstract

SummaryIn the past few years, the usefulness of transient expression assays has continuously increased for the characterization of unknown gene function and metabolic pathways. In grapevine (Vitis vinifera L.), one of the most economically important fruit crops in the world, recent systematic sequencing projects produced many gene data sets that require detailed analysis. Due to their rapid nature, transient expression assays are well suited for large-scale genetic studies. Although genes and metabolic pathways of any species can be analysed by transient expression in model plants, a need for homologous systems has emerged to avoid the misinterpretation of results due to a foreign genetic background. Over the last 10 years, various protocols have thus been developed to apply this powerful technology to grapevine. Using cell suspension cultures, somatic embryos, leaves or whole plantlets, transient expression assays enabled the study of the function, regulation and subcellular localization of genes involved in specific metabolic pathways such as the biosynthesis of phenylpropanoids. Disease resistance genes that could be used for marker-assisted selection in conventional breeding or for stable transformation of elite cultivars have also been characterized. Additionally, transient expression assays have proved useful for shaping new tools for grapevine genetic improvement: synthetic promoters, silencing constructs, minimal linear cassettes or viral vectors. This review provides an update on the different tools (DNA constructs, reporter genes, vectors) and methods (Agrobacteriummediated and direct gene transfer methods) available for transient gene expression in grapevine. The most representative results published thus far are then described.

Cultivar-specific gene modulation in Vitis vinifera: analysis of the promoters regulating the expression of WOX transcription factors

“…This approach has proven effective in grapevine440 and it represents a good alternative to stable genetic transformation that is still a time consuming process in grapevine21.…”

A reliable protocol for the stable transformation of non-embryogenic cells cultures of grapevine (Vitis vinifera L.) and Taxus x media

“…Genetic engineering offers new tools for studies that address the functional characterization of genes of interest in grapevine. Several groups have published reports on the transformation of Vitis [33][34][35][36][37][38][39][40]. To date, Gollop et al [41] have provided evidence for the stable transformation of non-embryogenic cultures (NEC).…”

Development and Use of Biotechnology Tools for Grape Functional Analysis

“…The final determination of factors that modulate transgene expression must ultimately be made only following introduction to plant cells for stable transformation. Methods for molecule transfer in grapevine involve biological methods (Agrobacterium-mediated transformation) for indirect gene transfer or chemical/physical methods (biolistics, electroporation, and protoplasts) for direct gene transfer to plant cells [61,62] (Figure 2). …”