title: Molecular cloning, functional characterization and expression analysis of a novel monosaccharide transporter gene OsMST6 from rice (Oryza sativa L.).
abstract: Monosaccharides transporters play important roles in assimilate supply for sink tissue development. In this study, a new monosaccharide transporter gene OsMST6 was identified from rice (Oryza sativa L.). The predicted OsMST6 protein shows typical features of sugar transporters and shares 79.6% identity with the rice monosaccharide transporter OsMST3. Heterologous expression in yeast (Saccharomyces cerevisiae) demonstrated that OsMST6 is a broad-spectrum monosaccharide transporter, with a K (m) of 266.1 muMu for glucose. OsMST6-green fluorescent protein fusion protein is localized to the plasma membrane in plant. Semi-quantitative RT-PCR analysis exhibited that OsMST6 is expressed in all tested organs/tissues. In developing seeds, OsMST6 expression level is high at the early and middle grain filling stages and gradually declines later. Further analysis detected its expression in both maternal and filial tissues. RNA in situ hybridization analysis indicated that OsMST6 is predominantly expressed in the vascular parenchyma of the chalazal vein, cross-cells, nucellar tissue and endosperm of young seeds, in mesophyll cells of source leaf blades, and in pollens and the connective vein of anthers. In addition, OsMST6 expression is up-regulated by salt stress and sugars. The physiological role of OsMST6 for seed development and its roles in other sink and source tissues are discussed.
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Beijing, China.
authors.forename: Yongqin
authors.initials: Y
authors.lastname: Wang
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Xiao
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chenglin
authors.initials: C
authors.lastname: Chai
authors.forename: Gang
authors.initials: G
authors.lastname: Wei
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wei
authors.forename: Honglin
authors.initials: H
authors.lastname: Xu
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Pieter B F
authors.initials: PB
authors.lastname: Ouwerkerk
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhu
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D018744:DNA, Plant; D015870:Gene Expression; D017343:Genes, Plant; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D012275:Oryza / Q000235:genetics* / Q000502:physiology*; D010802:Phylogeny; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D011993:Recombinant Fusion Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D009004:Monosaccharide Transport Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins