JXB Advance Access originally published online on April 23, 2007
Journal of Experimental Botany 2007 58(8):1985-1997; doi:10.1093/jxb/erm061
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
RESEARCH PAPER |
Isolation, functional characterization, and expression analysis of grapevine (Vitis vinifera L.) hexose transporters: differential roles in sink and source tissues*
Commonwealth Scientific and Industrial Research Organization, Plant Industry, Glen Osmond, South Australia 5064, Australia
To whom correspondence should be addressed. E-mail: ian.dry{at}csiro.au
Three hexose transporters (VvHT3, VvHT4, and VvHT5) were cloned from Vitis vinifera L. and functionally characterized in the hexose transport-impaired Saccharomyces cerevisiae mutant EBY.VW4000. Both VvHT4 and VvHT5 facilitated glucose uptake, with Kms of 137 µM and 89 µM, respectively. VvHT3 was not functional in the yeast system but a VvHT3:GFP (green fluorescent protein) fusion protein was targeted to the plasma membrane in plant cells. In young ‘sink’ leaves, transcript levels of all five VvHTs and a cell wall invertase (VvcwINV) were low. In mature leaves, there were increased levels of VvHT1, VvHT3, VvHT5, and VvcwINV transcripts, suggesting that mature leaves may have an increased capacity for apoplastic sucrose hydrolysis and hexose retrieval. In grape berries, VvHT1, VvHT2, and VvHT3 transcript levels were found to be significantly higher than those of VvHT4 and VvHT5. VvHT1 was most highly expressed early in berry development but decreased during the period of rapid sugar accumulation, while VvHT2 and VvHT3 expression remained high during this accumulation phase. VvcwINV expression occurred throughout berry development but peaked just prior to veraison. It is clear that the machinery to transport the hexose molecules produced through the cleavage of sucrose, by cell wall invertase, is present in the berry. This agrees with the suggestion that hexose accumulation to high levels during the ripening phase occurs through an apoplastic pathway. Interestingly, there is no direct relationship between VvHT gene expression and hexose accumulation, which suggests either that transcription is not the main determinant of transport activity or that other transport pathways are also active.
Key words: Grape, hexose transporter, sink, Vitis
* Nucleotide sequence data from this article have been deposited with the GenBank data library under accession numbers AY538259, AY538260, and AY538261 for VvHT3, VvHT4, and VvHT5, respectively.
Present address: Discipline of Wine and Horticulture, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia
Received 17 January 2007; Revised 23 February 2007 Accepted 27 February 2007
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  H. Wada, M. A. Matthews, and K. A. Shackel Seasonal pattern of apoplastic solute accumulation and loss of cell turgor during ripening of Vitis vinifera fruit under field conditions J. Exp. Bot., April 1, 2009; 60(6): 1773 - 1781. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. T. Matus, R. Loyola, A. Vega, A. Pena-Neira, E. Bordeu, P. Arce-Johnson, and J. A. Alcalde Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera J. Exp. Bot., March 1, 2009; 60(3): 853 - 867. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Terrier, L. Torregrosa, A. Ageorges, S. Vialet, C. Verries, V. Cheynier, and C. Romieu Ectopic Expression of VvMybPA2 Promotes Proanthocyanidin Biosynthesis in Grapevine and Suggests Additional Targets in the Pathway Plant Physiology, February 1, 2009; 149(2): 1028 - 1041. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Zamboni, L. Minoia, A. Ferrarini, G. B. Tornielli, E. Zago, M. Delledonne, and M. Pezzotti Molecular analysis of post-harvest withering in grape by AFLP transcriptional profiling J. Exp. Bot., November 13, 2008; (2008) ern256v1. [Abstract] [Full Text] [PDF]
|
|