The Molecular Regulation of Carbon Sink Strength in Grapevine (Vitis vinifera L.).

You-Mei Li,Feng Leng,Charles Forney,Zhao-Sen Xie,Bhaskar Bondada

doi:10.3389/fpls.2020.606918

You-Mei Li, Feng Leng + Show 3 more

Open Access

https://doi.org/10.3389/fpls.2020.606918

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Abstract

Sink organs, the net receivers of resources from source tissues, provide food and energy for humans. Crops yield and quality are improved by increased sink strength and source activity, which are affected by many factors, including sugars and hormones. With the growing global population, it is necessary to increase photosynthesis into crop biomass and yield on a per plant basis by enhancing sink strength. Sugar translocation and accumulation are the major determinants of sink strength, so understanding molecular mechanisms and sugar allocation regulation are conducive to develop biotechnology to enhance sink strength. Grapevine (Vitis vinifera L.) is an excellent model to study the sink strength mechanism and regulation for perennial fruit crops, which export sucrose from leaves and accumulates high concentrations of hexoses in the vacuoles of fruit mesocarp cells. Here recent advances of this topic in grape are updated and discussed, including the molecular biology of sink strength, including sugar transportation and accumulation, the genes involved in sugar mobilization and their regulation of sugar and other regulators, and the effects of hormones on sink size and sink activity. Finally, a molecular basis model of the regulation of sugar accumulation in the grape is proposed.

Highlights

With an increasing global population estimated to reach 9 billion people by 2050 (Nelson et al, 2012), a dramatic increase in agricultural productivity must occur
This review focuses on the mechanism related to the formation and regulation of sink strength in grape, including the molecular mechanism of sugar transport and accumulation, the genes involved in sugar allocation and its regulation, the genetic regulation of hormones and their role in regulating sugar transport, phloem unloading, and metabolism
Glucose could regulate the expression of monosaccharide transporters (VvHT3, VvHT4, VvHT5, and VvHT6) by inducing VvSK1 transcription, a Glycogen Synthase Kinase3 protein kinase that modulates sugar uptake and accumulation in grape (Lecourieux et al, 2010)

Summary

Introduction

With an increasing global population estimated to reach 9 billion people by 2050 (Nelson et al, 2012), a dramatic increase in agricultural productivity must occur. Studies on grapes have shown that the vital step controlling sugar accumulation is determined within the developing fruit rather than the source leaves’ ability to export photosynthetic products or the transport efficiency of the phloem pathway (Zhang et al, 2006; Xie et al, 2009). The external factors involved in regulating the sink activity, including sugar phloem unloading and sugar accumulation in the sink cells, could strongly affect sink strength in the grape.

Results

Conclusion