Sugar transporters involved in flowering and grain development of rice

Developing seeds offer a fine experimental system for study on sugar transport mechanism(s) in sink tissue. The sugar transporters identified as being specific to the seed development may play a crucial role for flowering and grain development. The rice sucrose transporter OsSUTI and the monosaccharide transporters OsMST1-3 have been previously characterized. To investigate sugar transport processes during flowering and in developing grains of rice, we newly isolated two genomic clones OsSUT2 (Oryza sativa sucrose transporter 2) and OsMST5 (Oryza sativa monosaccharide transporter 5) and their corresponding cDNAs. OsSUT2 and OsMST5 are encoded by open reading frames of 1485 and 1557bp encoding 495 and 519 amino acids, respectively. The putative amino acid sequence of OsSUT2 showed 63.0 and 62.4 % identity to that of OsSUTI and barley transporter HvSUT1, respectively. Northern blot analysis revealed that OsSUT2 and OsMST5 mRNA accumulates in panicles before pollination. In situ hybridization analysis showed that OsSUT2 transcript is specific to the developing pollen. These data presented suggest that both OsSUT2 and OsMST5 play a role during the development at the early stage of the seed development. On the other hand OsSUTI was expressed at the early stage of the grain development, suggesting a different physiological role compared to OsSUT2.

[1]  A. Krogh,et al.  Predicting transmembrane protein topology with a hidden Markov model: application to complete genomes. , 2001, Journal of molecular biology.

[2]  P. Perata,et al.  Sugar uptake and transport in rice embryo. Expression of companion cell-specific sucrose transporter (OsSUT1) induced by sugar and light. , 2000, Plant physiology.

[3]  J. Yamaguchi,et al.  Characterization and expression of monosaccharide transporters (osMSTs) in rice. , 2000, Plant & cell physiology.

[4]  L. Williams,et al.  Sugar transporters in higher plants--a diversity of roles and complex regulation. , 2000, Trends in plant science.

[5]  A. Weber,et al.  Identification, Purification, and Molecular Cloning of a Putative Plastidic Glucose Translocator , 2000, Plant Cell.

[6]  U. Wobus,et al.  Sucrose transport into barley seeds: molecular characterization of two transporters and implications for seed development and starch accumulation. , 2000, The Plant journal : for cell and molecular biology.

[7]  N. Aoki,et al.  Molecular cloning and expression analysis of a gene for a sucrose transporter in maize (Zea mays L.). , 1999, Plant & cell physiology.

[8]  E. Truernit,et al.  A male gametophyte-specific monosaccharide transporter in Arabidopsis. , 1999, The Plant journal : for cell and molecular biology.

[9]  B. Ylstra,et al.  Hexose transport in growing petunia pollen tubes and characterization of a pollen-specific, putative monosaccharide transporter. , 1998, Plant physiology.

[10]  Erik L. L. Sonnhammer,et al.  A Hidden Markov Model for Predicting Transmembrane Helices in Protein Sequences , 1998, ISMB.

[11]  U. Wobus,et al.  A role for sugar transporters during seed development: molecular characterization of a hexose and a sucrose carrier in fava bean seeds. , 1997, The Plant cell.

[12]  U. Wobus,et al.  Sugar import and metabolism during seed development , 1997 .

[13]  R. Furbank,et al.  cDNA cloning and tissue specific expression of a gene for sucrose transporter from rice (Oryza sativa L.). , 1997, Plant & cell physiology.

[14]  N. Sauer,et al.  Expression of the PmSUC1 sucrose carrier gene from Plantago major L. is induced during seed development. , 1996, The Plant journal : for cell and molecular biology.

[15]  S. Fieuw,et al.  Efflux of photosynthate and acid from developing seed coats of Phaseolus vulgaris L.: a chemiosmotic analysis of pump-driven efflux , 1995 .

[16]  C. Offler,et al.  A Novel Experimental System for Studies of Photosynthate Transfer in the Developing Wheat Grain , 1993 .

[17]  M. Saier,et al.  A major superfamily of transmembrane facilitators that catalyse uniport, symport and antiport. , 1993, Trends in biochemical sciences.

[18]  S. Baldwin,et al.  Sugar-cation symport systems in bacteria. , 1992, International review of cytology.

[19]  J. H. Thorne.  Phloem unloading of C and N assimilates in developing seeds , 1985 .

[20]  K. Oparka,et al.  Movement of fluorescein into isolated caryopses of wheat and barley , 1983 .

[21]  J. Shannon,et al.  Movement of 14C-labeled Sugars into Kernels of Wheat (Triticum aestivum L.) , 1975 .

[22]  J. Palmer.  Temperature Sensitivity of the Latent Phase in Ethylene-induced Elongation. , 1975, Plant physiology.

[23]  F. A. Sakri.  Movement of C-labeled Sugars into Kernels of Wheat (Triticum aestivum L.). , 1975, Plant physiology.

[24]  S. Zee.  Vascular Tissue and Transfer Cell Distribution in the Rice Spikelet , 1972 .

[25]  S. Zee,et al.  Studies on the Ontogeny of the Pigment Strand in the Caryopsis of Wheat , 1970 .