Molecular genetic mechanisms of sugar transport in plants in the absence and during arbuscular mycoryza development

Abstract

The review is aimed to analyze molecular mechanisms of carbohydrate transport during the formation of arbuscular mycorrhiza (AM), a widespread symbiosis of plants with Glomeromycotina subdivision fungi. Due to AM-symbiosis, plants receive microelements, mainly phosphorus, and fungi are supplied by products of carbon assimilation. The study of sugar transport mechanisms in plants as well as between plants and symbiont is methodologically difficult because of the obligatory status of AM fungi. The mechanisms of carbohydrate transport in leaf and root cells are concerned, particular interest is paid to transporters, specific to AM structures. Several resumptive schemes are designed. SWEET family of transporters (Sugars Will Eventually be Exported Transporters), including AM-specific uniporters are reviewed. We summarize results on expression of genes encoding transporter in cells of plants without AM, in AM-plant cells with arbuscules and AM-plant cells without arbuscules. The data on genes of MST proteins family (Monosaccharide Transporters) participating in direct transport of sugars from the soil to the foliar mycelium of AM fungi are considered.

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

“…Localization scheme of the SWEET transporters in a cell with an arbuscule (Guo et al, 2014;Lin et al, 2014;Chandran, 2015;Chen et al, 2015;Ait Lahmidi et al, 2016;Kryvoruchko et al, 2016;Manck-Götzenberger, Requena, 2016;Sugiyama et al, 2017;Hennion et al, 2019;Jeena et al, 2019;Yurkov et al, 2019).…”

AM-Induced Alteration in the Expression of Genes, Encoding Phosphorus Transporters and Enzymes of Carbohydrate Metabolism in Medicago lupulina

“…The mycelium of the AM fungi probably receives carbohydrates from the apoplast of the root cortex [5] as glucose [46], and less as sucrose [2]. The exact location and mechanism of carbon transfer from host plants to AM fungi is not yet fully discovered, but it is the focus of recent studies of plant-microbial symbiotic interactions [17,18,[27][28][29]33].…”

“…Plant sugar transporters are integrated in three key families: the sucrose/H + -symporter Sucrose Transporter (SUT), Monosaccharide Transporters (MST), including the Sugar Transport Protein subfamily (STP), etc., and Sugars Will Eventually be Exported Transporters (SWEETs). For some plant species, Sucrose Facilitator (SUF) and Chloroplast Maltose Exporter (MEX) transporters have additionally been identified [33]. These transporters have been shown to be involved in the transport of sugars in AM plants.…”

“…There are still gaps in the scheme of carbohydrate metabolism and phosphate/carbohydrate transport in plants with and without AM fungi [33]. New approaches such as transcriptomic, proteomic and metabolic analyses are used in recent studies.…”

“…Approximately 1 µg of the total RNA was selected for synthesis. Genes of interest were selected based on an analysis of the literature [33,77]. Ten homologues of the phosphorus transport and carbohydrate metabolism genes in M. truncatula were selected.…”