Genome-Wide Identification and Expression Analysis of the SUT Family from Three Species of Sapindaceae Revealed Their Role in the Accumulation of Sugars in Fruits

Abstract

Sapindaceae is an economically important family of Sapindales and includes many fruit crops. The dominant transport and storage form of photoassimilates in higher plants is sucrose. Sucrose transporter proteins play an irreplaceable role in the loading, transportation, unloading, and distribution of sucrose. A few SUT (sugar transporter) family genes have been identified and characterized in various plant species. In this study, 15, 15, and 10 genes were identified in litchi, longan, and rambutan, respectively, via genome-wide screening. These genes were divided into four subgroups based on phylogenetics. Gene duplication analysis suggested these genes underwent potent purifying selection and tandem duplications during evolution. The expression levels of SlSut01 and SlSut08 were significantly increased in the fruits of Sapindaceae members. The homologs of these two genes in longan and rambutan were also highly expressed in the fruits. The expression pattern of SUTs in three organs of the two varieties was also explored. Subcellular colocalization experiments revealed that the proteins encoded by both genes were present in the plasma membrane. This report provides data for the functional study of SUTs in litchi and provides a basis for screening sugar accumulation-related genes in fruits of Sapindaceae.

From acidity to sweetness: a comprehensive review of carbon accumulation in grape berries

“…During ripening, the berries accumulate high concentration of hexoses (1.1 M) in the vacuoles of flesh cells (Shahood et al 2020 ; Du et al 2023 ). The sweetness of grape berries impacts directly the sensory quality of berries and wine (Conde et al 2007 ; Yang et al 2023 ; Jiang et al 2024 ). Sugar accumulation in the berries is a finely tuned outcome of numerous physiological processes including photosynthesis in the leaves, long-distance transport in phloem and unloading in sink organs (Martínez-Esteso et al 2011 ; Lecourieux et al 2014 ; Castellarin et al 2016 ; Zhang et al 2019 ; Martínez-Lüscher and Kurtural 2023 ).…”