Location: Plant, Soil and Nutrition ResearchTitle: A tomato vacuolar invertase inhibitor mediates sucrose metabolism an influences fruit ripening
|Qin, Guozheng - Institute Of Botany - China|
|Zhu, Zhu - Institute Of Botany - China|
|Wang, Weihao - Institute Of Botany - China|
|Cai, Jianghua - Institute Of Botany - China|
|Chen, Yong - Institute Of Botany - China|
|Tian, Shiping - Institute Of Botany - China|
Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2016
Publication Date: 12/23/2016
Citation: Qin, G., Zhu, Z., Wang, W., Cai, J., Chen, Y., Li, L., Tian, S. 2016. A tomato vacuolar invertase inhibitor mediates sucrose metabolism an influences fruit ripening. Plant Physiology. 172:1596-1611.
Interpretive Summary: Fleshy fruits are rich in various nutrients, which make them a critical component of human diets. Invertase and its inhibitors regulate sugar levels and composition in fruit. In this study, a set of genes involved in sucrose synthesis and degradation, including vacuolar invertase and vacuolar invertase inhibitors were identified in tomato as RIN direct targets. Modification of vacuolar invertase inhibitors expression to alter sugar metabolism greatly affects pigment formation and fruit ripening. These findings provide strong in vivo evidence for the role of sucrose in promoting pigment biosynthesis and fruit ripening, and establish vacuolar invertase inhibitors as a novel genetic tool for mediating fruit ripening.
Technical Abstract: Fruit ripening is a complex process that involves a series of physiological and biochemical changes that ultimately influence fruit quality traits, such as color and flavor. Sugar metabolism is an important factor in ripening and there is evidence that it influences various aspects of ripening, although the associated mechanism is not well understood. In this study, we identified and analyzed the expression of 36 genes involved in sucrose metabolism in ripening tomato (Solanum lycopersicum) fruit. Chromatin immunoprecipitation and gel mobility shift assays indicated that SlVIF, which encodes a vacuolar invertase inhibitor, and SlVI, encoding a vacuolar invertase, are directly regulated by the global fruit ripening regulator RIN (RIPENING INHIBITOR). Moreover, we showed that SlVIF physically interacts with SlVI to control sucrose metabolism. Repression of SlVIF by RNA interference (RNAi) delayed tomato fruit ripening, while overexpression of SlVIF accelerated ripening, with concomitant changes in lycopene production and ethylene biosynthesis. An iTRAQ (isobaric tags for relative and absolute quantification)-based quantitative proteomic analysis further indicated that the abundance of a set of proteins involved in fruit ripening was altered by suppressing SlVIF expression, including proteins associated with lycopene generation and ethylene synthesis. These findings provide evidence for the role of sucrose in promoting fruit ripening and establish that SlVIF contributes to fruit quality and the RIN-mediated ripening regulatory mechanisms, which are of significant agricultural value.