Molecular cloning and expression analysis of a monosaccharide transporter gene OsMST4 from rice (Oryza sativa L.)

Abstract

Monosaccharide transporters mediate the membrane transport of a variable range of monosaccharides, which plays a crucial role in sugar distribution throughout the plant. To investigate the significance of monosaccharide transporters for rice (Oryza sativa L.) seed development, cDNA of a new putative monosaccharide transporter gene OsMST4 was isolated. The deduced OsMST4 protein shows typical features of monosaccharide transporters, and shares high homology with other plant homologues. Heterologous expression in yeast (Saccharomyces cerevisiae) showed that OsMST4 is a functional monosaccharide transporter capable of transporting glucose, fructose, mannose and galactose. Transcriptional analysis revealed that OsMST4 is expressed in all tested organs/tissues. In developing caryopses, its expression is high at the early and middle grain filling stages, and declines gradually to low levels after that. Further analysis revealed that it is expressed in both the maternal tissue and the filial tissue, with its highest expression in embryo. Cellular location in young caryopses through RNA in situ hybridization showed that OsMST4 mRNA mainly accumulates in the vascular parenchyma of the chalazal vein, cross-cells, nucellar tissue and endosperm. The expression pattern of OsMST4 was further confirmed by histochemical analysis of the OsMST4-promoter-beta-glucuronidase (GUS) transgenic rice plants. These data indicate that OsMST4 is actively involved in monosaccharides supply for seed development during the course of grain filling. In addition, the cell type-specific expression patterns of OsMST4 in other sink and source tissues were also investigated, and its corresponding physiological roles were discussed.

Down-Regulating CsHT1, a Cucumber Pollen-Specific Hexose Transporter, Inhibits Pollen Germination, Tube Growth, and Seed Development

“…1; Supplemental Figs. S1 and S2; Büttner and Sauer, 2000;Wang et al, 2007). It shares especially high homology with the Arabidopsis genes AtSTP4, AtSTP9, and AtSTP11 and petunia gene Pmt1, which have been reported to be expressed mainly in pollen grain and the pollen tube ( Fig.…”

“…By contrast, pollen tubes of petunia (Petunia hybrida) grow equally well on medium containing Glc, Fru, or Suc (Ylstra et al, 1998). Although several hexose transporter genes are highly expressed in pollen grains or pollen tubes of Arabidopsis (Büttner, 2010) and rice (Oliver et al, 2007a;Wang et al, 2007Wang et al, , 2008, single knockouts of these genes do not result in a phenotype, and in vitro experiments demonstrate that the germination of Arabidopsis pollen seems to be strictly dependent on Suc in the medium. Addition of Glc causes instant bursting of Arabidopsis pollen tubes (Schneidereit et al, 2003(Schneidereit et al, , 2005Scholz-Starke et al, 2003).…”

Carbon Starved AntherEncodes a MYB Domain Protein That Regulates Sugar Partitioning Required for Rice Pollen Development

“…Similarly, Arabidopsis STP6 , STP9 (Schneidereit et al, 2003), and STP11 (Schneidereit et al, 2005) have been shown to be expressed during anther/pollen development. Also, several MSTs from rice have been demonstrated to play a crucial role in sugar distribution (Toyofuku et al, 2000;Ngampanya et al, 2003;Mamun et al, 2006;Wang et al, 2007Wang et al, , 2008b.…”

Molecular cloning, functional characterization and expression analysis of a novel monosaccharide transporter gene OsMST6 from rice (Oryza sativa L.)

“…The MST gene family in Arabidopsis is investigated in more detail than in other species. Up to now, six MSTs from rice (Toyofuku et al 2000;Ngampanya et al 2003;Mamun et al 2006;Wang et al 2007) and two from barley (Weschke et al 2003) have been studied, but MSTs from other cereals such maize and wheat have not been reported.…”

“…Monosaccharide transporters expressed in both sink and source organs/tissues have also been found in tomato (Gear et al 2000), grapevine (Hayes et al 2007) and rice (Toyofuku et al 2000;Wang et al 2007). The Arabidopsis AtSTP3 is the only MST speciWcally expressed in source organs/tissues .…”