DsSWEET17, a Tonoplast-Localized Sugar Transporter from Dianthus spiculifolius, Affects Sugar Metabolism and Confers Multiple Stress Tolerance in Arabidopsis.

Aimin Zhou,Hongping Ma,Shuang Feng,Shufang Gong,Jingang Wang

doi:10.3390/ijms19061564

Abstract

Plant SWEETs (Sugars Will Eventually be Exported Transporters) affect the growth of plants by regulating the transport of sugar from source to sink and its intracellular transport between different organelles. In this study, DsSWEET17 from Dianthus spiculifolius was identified and characterized. Real-time quantitative PCR analysis revealed that the expression of DsSWEET17 was affected by exogenous application of fructose and glucose as well as under salt, osmotic, and oxidation stress. Colocalization experiments showed that the DsSWEET17-GFP (green fluorescent protein) fusion protein was localized to the FM4-64-labeled tonoplasts in Arabidopsis. Compared to the wild type, the transgenic Arabidopsis seedlings overexpressing DsSWEET17 had longer roots, greater fresh weight, and a faster root growth upon exogenous application of fructose. Furthermore, transgenic Arabidopsis seedlings had significantly higher fructose accumulation than was observed for the wild-type seedlings. The analysis of root length revealed that transgenic Arabidopsis had higher tolerance to salt, osmotic, and oxidative stresses. Taken together, our results suggest that DsSWEET17 may be a tonoplast sugar transporter, and its overexpression affects sugar metabolism and confers multiple stress tolerance in Arabidopsis.

Highlights

Sucrose, glucose, and fructose are the main sugars present in plants
Colocalization experiments confirmed that DsSWEET17-green fluorescent protein (GFP) was mainly localized to the tonoplast, which was labeled with the vacuolar membrane marker, FM4-64, dye, in Arabidopsis root cells (Figure 3B,C)
The analysis of sugar content showed that the content of fructose in the transgenic seedlings was significantly higher than that in the WT seedlings (Figure 6), indicating that the overexpression of DsSWEET17 affects the accumulation of fructose in Arabidopsis

Summary

Introduction

Glucose, and fructose are the main sugars present in plants. They are the sources of carbon and energy, and their transport, distribution, and utilization play key roles in plant growth and response to biotic and abiotic stresses [1,2,3]. Plant H+-independent sugar transporter SWEETs (Sugars Will Eventually be Exported Transporters) are a class of mono- and disaccharide transporters with seven conserved transmembrane domains [3,4]. They have been identified and annotated from several species with the published genomes, including Arabidopsis thaliana [5], Oryza sativa [6], and Sorghum bicolor [7]

Methods

Results

Conclusion