Vacuole: a repository to control fruit flavor quality

Abstract

The content of sugar and organic acid is the main factor that determines the fruit flavor quality and yield. More specifically, the ratio of sugar to organic acid affects the taste and nutritional value of fruits. Vacuoles and vacuolar transporters play pivotal roles in regulating fruit sugar and acid content, as most of the sugars and acids are transported and stored in ripe fruit vacuoles. In the past decades, the increasing vacuolar transporters or channels were reported to be involved in the sugars and acids' accumulation in horticultural fruits. This article specifically summarized the sugar, acid transporters and proton pumps that have been identified to be located in the vacuole membrane in horticultural crops, and described their physiological functions in the formation of flavor quality of main fruit crops in combination with their transport activities. Moreover, the research strategies and effective technical methods for functional analysis of vacuolar transporters were also discussed in this review.