A Novel Sugar Transporter from Dianthus spiculifolius, DsSWEET12, Affects Sugar Metabolism and Confers Osmotic and Oxidative Stress Tolerance in Arabidopsis.

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

doi:10.3390/ijms19020497

Abstract

Plant SWEETs (sugars will eventually be exported transporters) play a role in plant growth and plant response to biotic and abiotic stresses. In the present study, DsSWEET12 from Dianthus spiculifolius was identified and characterized. Real-time quantitative PCR analysis revealed that DsSWEET12 expression was induced by sucrose starvation, mannitol, and hydrogen peroxide. Colocalization experiment showed that the DsSWEET12-GFP fusion protein was localized to the plasma membrane, which was labeled with FM4-64 dye, in Arabidopsis and suspension cells of D. spiculifolius. Compared to wild type plants, transgenic Arabidopsis seedlings overexpressing DsSWEET12 have longer roots and have a greater fresh weight, which depends on sucrose content. Furthermore, a relative root length analysis showed that transgenic Arabidopsis showed higher tolerance to osmotic and oxidative stresses. Finally, a sugar content analysis showed that the sucrose content in transgenic Arabidopsis was less than that in the wild type, while fructose and glucose contents were higher than those in the wild type. Taken together, our results suggest that DsSWEET12 plays an important role in seedling growth and plant response to osmotic and oxidative stress in Arabidopsis by influencing sugar metabolism.

Highlights

Plants produce sugar in leaf mesophyll cells by photosynthesis
In Arabidopsis, AtSWEET12 is localized to the plasma membrane of phloem parenchyma cells and mediates phloem loading of sucrose [17]
Colocalization experiments confirmed that DsSWEET12-green fluorescent protein (GFP) was mainly localized to the plasma membrane, which was labeled with FM4-64 dye, in Arabidopsis root hair and D. spiculifolius suspension cells (Figure 3B,C)

Summary

Introduction

Plants produce sugar in leaf mesophyll cells by photosynthesis. These sugars, mostly sucrose, are imported via bundle sheaths into phloem cells and transported to growing parts of the plant [1]. Plant SWEETs (sugars will eventually be exported transporters) are a class of H+-independent mono- and disaccharide transporters [1,4]. They comprise a large gene family and have been identified from several species including Arabidopsis thaliana [5], Oryza sativa [6], Sorghum bicolor [7], and Citrus sinensis [8]

Methods

Results

Conclusion