Sugar transporters of the SWEET family and their role in arbuscular mycorrhiza.

A. A. Kryukov,A. P. Yurkov,O. I. Yakhin,U. M. Malikov,M. F. Shishova,A. A. Lubyanov,T. R. Kudriashova,A. P. Kozhemyakov,A. O. Gorbunova

doi:10.18699/vj21.086

Abstract

Plant sugar transporters play an essential role in the organism’s productivity by carrying out carbohydrate transportation from source cells in the leaves to sink cells in the cortex. In addition, they aid in the regulation of a substantial part of the exchange of nutrients with microorganisms in the rhizosphere (bacteria and fungi), an ty essential to the formation of symbiotic relationships. This review pays special attention to carbohydrate nutrition during the development of arbuscular mycorrhiza (AM), a symbiosis of plants with fungi from the Glomeromycotina subdivision. This relationship results in the host plant receiving micronutrients from the mycosymbiont, mainly phosphorus, and the fungus receiving carbon assimilation products in return. While the eff icient nutrient transport pathways in AM symbiosis are yet to be discovered, SWEET sugar transporters are one of the three key families of plant carbohydrate transporters. Specif ic AM symbiosis transporters can be identif ied among the SWEET proteins. The survey provides data on the study history, structure and localization, phylogeny and functions of the SWEET proteins. A high variability of both the SWEET proteins themselves and their functions is noted along with the fact that the same proteins may perform different functions in different plants. A special role is given to the SWEET transporters in AM development. SWEET transporters can also play a key role in abiotic stress tolerance, thus allowing plants to adapt to adverse environmental conditions. The development of knowledge about symbiotic systems will contribute to the creation of microbial preparations for use in agriculture in the Russian Federation.

Highlights

Sugar transporters in plants are customarily divided into three major classes: SUT (SUC), MST, and SWEET (Sugars Will Eventually be Exported Transporters)
The aim of the current research is to provide an overview of the data on gene phylogenesis inside the SWEET class and functions of the proteins encoded with the aforementioned genes as well as to assess their role in the sugar transportation process during the formation of arbuscular mycorrhiza (AM) symbiosis
SWEET proteins are essential for the trans portation of carbohydrates in plants

Summary

Introduction

Sugar transporters in plants are customarily divided into three major classes: SUT (SUC), MST (including STP, TMT, PMT, VGT, pGlct/SGB1, ESL, and INT subclasses), and SWEET (Sugars Will Eventually be Exported Transporters). SUT carry out long-distance transportation of sucrose from plant leaves to the targeted plant organs and tissues They disintegrate into monosaccharides and are subsequently transported by MST proteins. Proteins specific to AM symbiosis may be detected inside the SWEET transporter group (Chen et al, 2010). Seventeen different transporters were discovered, described, and named according to the species belonging to a particular plant and the protein number Afterwards SWEET proteins were found in a number of other plant species and in animals and prokaryotes (the latter were named SemiSWEET) (Chen et al, 2012; Feng et al, 2015; Patil et al, 2015; Manck-Götzenberger, Requena, 2016; Hu L.P. et al, 2017). The nucleotide sequence, encoding TMH4, is known to be the most variable of TMHs, and its origin is currently being debated (Jeena et al, 2019)

AtSWEET15

Findings

Conclusion