Genome-Wide Identification and Expression Analysis of Sugar Transporter (ST) Gene Family in Longan (Dimocarpus longan L.)

Abstract

Carbohydrates are nutrients and important signal molecules in higher plants. Sugar transporters (ST) play important role not only in long-distance transport of sugar, but also in sugar accumulations in sink cells. Longan (Dimocarpus longan L.) is one of the most important commercial tropical/subtropical evergreen fruit species in Southeast Asia. In this study, a total of 52 longan sugar transporter (DlST) genes were identified and they were divided into eight clades according to phylogenetic analysis. Out of these 52 DlST genes, many plant hormones (e.g., MeJA and gibberellin), abiotic (e.g., cold and drought), and biotic stress responsive element exist in their promoter region. Gene structure analysis exhibited that each of the clades have closely associated gene architectural features based on similar number or length of exons. The numbers of DlSTs, which exhibited alternative splicing (AS) events, in flower bud is more than that in other tissues. Expression profile analysis revealed that ten DlST members may regulate longan flowerbud differentiation. In silico expression profiles in nine longan organs indicated that some DlST genes were tissue specificity and further qRT-PCR analysis suggested that the transcript level of seven DlSTs (DlINT3, DlpGlcT1, DlpGlcT2, DlPLT4, DlSTP1, DlVGT1 and DlVGT2) was consistent with sugar accumulation in fruit, indicating that they might be involved in sugar accumulations during longan fruit development. Our findings will contribute to a better understanding of sugar transporters in woody plant.

Sugar Transporter ZjSWEET2.2 Mediates Sugar Loading in Leaves of Ziziphus jujuba Mill

“…By now, sugar transporters found in plants mainly include three types: monosaccharide transporters (MST), sucrose transporters (SUT) and SWEET transporters (Sugars Will Eventually be Exported Transporters). Of these, MSTs and SUTs have typical structural characteristics of the major facilitator superfamily (MFS) with high hydrophobicity and generally include 12 transmembrane domains ( Fang et al., 2020 ), which is the most important membrane transporter family. SUTs are crucial for the sucrose long-distance transportation in phloem to sink organs as sucrose is the important form of photosynthetic products ( Chandran et al., 2003 ; Scofield et al., 2007 ).…”

Characterization of the SWEET Gene Family in Longan (Dimocarpus longan) and the Role of DlSWEET1 in Cold Tolerance

“…Sugar content is an important factor for determining fruits’ organoleptic quality [ 2 ]. As is shown in Figure 6 , the content of soluble sugars increased during fruit development and sucrose was the dominating soluble sugar in mature longan fruit.…”

“…Sugars are not only the predominant carbon and energy sources for both eukaryotes and prokaryotes, but also the essential signaling molecules for diverse physiological processes [ 1 ]. In addition, sugars are the main determiners of fruit quality and flavor [ 2 , 3 ]. In plants, sugars are the main products of photosynthesis, which occurs mainly in the stromal cells of the chloroplast, and are translocated to the sink organs via long-distance transport [ 4 , 5 ].…”

Identification and Bioinformatic Analysis of the GmDOG1-Like Family in Soybean and Investigation of Their Expression in Response to Gibberellic Acid and Abscisic Acid

“…The soybean genome and protein sequences were downloaded from Phytozome12 website ( ). The Hidden Markov Model (HMM) of conservative structure domain of DOG1 (PF14144) was downloaded from the PFAM database ( ) [ 13 , 31 , 32 ]. Predicted GmDOG1Ls were scanned with HMMER 3.1 software using the HMM of conserved domain of DOG1 [ 33 , 34 ].…”