Agroinfiltration of Strawberry Fruit — A Powerful Transient Expression System for Gene Validation

Agrobacterium-infiltration (agroinfiltration) transient expression systems facilitate rapid primary characterization of candidate gene function, protein localization, protein interacting partners, or other information from a delivered construct. Most of these characterizations have been performed in Nicotiana benthamiana leaves, which offer a limited set of cell types, metabolites, and developmental plasticity. As efforts to characterize genes associated with fruit and vegetable quality increase, the strawberry fruit has emerged as a useful tool to study the effects of transient gene expression. Introduction of active Agrobacterium cultures bearing loss- or gain-of-function constructs into developing fruits can provide robust gene silencing or modest overexpression within days of treatment. Fruits can then be assessed for transgene effects on endogenous gene expression, metabolism, physiology or development. The approach also allows introduction of VIGS-mediated silencing constructs as well as the assessment of promoter activity in fruits. This review details how the strawberry agroinfiltration system has been used as an efficient system to characterize an increasing number of genes associated with fruit development, physiology and metabolism.