The Sugar Transporter Inventory of Tomato: Genome-Wide Identification and Expression Analysis

Abstract

The mobility of sugars between source and sink tissues in plants depends on sugar transport proteins. Studying the corresponding genes allows the manipulation of the sink strength of developing fruits, thereby improving fruit quality for human consumption. Tomato (Solanum lycopersicum) is both a major horticultural crop and a model for the development of fleshy fruits. In this article we provide a comprehensive inventory of tomato sugar transporters, including the SUCROSE TRANSPORTER family, the SUGAR TRANSPORTER PROTEIN family, the SUGAR FACILITATOR PROTEIN family, the POLYOL/MONOSACCHARIDE TRANSPORTER family, the INOSITOL TRANSPORTER family, the PLASTIDIC GLUCOSE TRANSLOCATOR family, the TONOPLAST MONOSACCHARIDE TRANSPORTER family and the VACUOLAR GLUCOSE TRANSPORTER family. Expressed sequence tag (EST) sequencing and phylogenetic analyses established a nomenclature for all analyzed tomato sugar transporters. In total we identified 52 genes in tomato putatively encoding sugar transporters. The expression of 29 sugar transporter genes in vegetative tissues and during fruit development was analyzed. Several sugar transporter genes were expressed in a tissue- or developmental stage-specific manner. This information will be helpful to better understand source to sink movement of photoassimilates in tomato. Identification of fruit-specific sugar transporters might be a first step to find novel genes contributing to tomato fruit sugar accumulation.

Regulation of Sucrose Transporters and Phloem Loading in Response to Environmental Cues

“…The expression of SUT in leaves has been shown to differ markedly for different family members (Weise et al, 2000;Payyavula et al, 2011;Reuscher et al, 2014). The comparison of SUT expression levels under control conditions is in line with previous results, generally showing the SUT responsible for phloem loading as having the highest level of expression (Fig.…”

Genome-wide identification, phylogeny, and expression analysis of the SWEET gene family in tomato

“…For example, such studies have led to the identification of putative Receptor-like Kinases (RLKs) (Sakamoto et al, 2012), putative SUN, OFP, GABBY, transcriptions factors (Huang et al, 2013), 146 putative ERF proteins (Pirrello et al, 2012), ERECTA genes (Villagarcia et al, 2012), and MAPK (Kong et al, 2012), helicase (Xu et al, 2013), WRKY (Huang et al, 2012), and nucleobase-ascorbate transporter (NAT) gene family members (Cai et al, 2014). With a comprehensive inventory of all sucrose and monosaccharide transporters encoded in the tomato genome, Reuscher et al (2014) identified 52 genes putatively encoding sugar transporter proteins in the tomato reference genome. All these sugar transporter protein families belong to the MFS family which is characterized by 12 transmembrane domains (TMDs) and driven by the protonmotive force.…”

“…These transporters are characterized by 12 transmembrane domains (TMDs) (Doidy et al, 2012;Reuscher et al, 2014). The plant SWEET (Sugars Will Eventually be Exported Transporters) family of sugar transporters is a recently identified seven-TMD protein family (PFAM code PF0383) Xuan et al, 2013).…”

Fertilización foliar en el rendimiento y calidad de tomate en hidroponia bajo invernadero

“…Of the soluble solids, approximately 60% are sugars, mainly glucose and fructose (Gómez and Camelo, 2002), since the plant is highly necessary an adequate supply of these, nutrition and management are very important to achieve this goal (Reuscher et al, 2014). Among other important factors, nutrition is essential for an adequate concentration of °Brix in marketable fruits.…”

“…De los sólidos solubles, aproximadamente 60% son azucares, principalmente glucosa y fructosa (Gómez y Camelo, 2002), dado que en la planta es altamente necesario un suministro adecuado de estos, la nutrición y manejo son muy importantes para lograr tal fin (Reuscher et al, 2014). Entre otros factores de importancia, la nutrición es fundamental para una adecuada concentración de °Brix en frutos comercializables.…”