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OPTI-2 Résumé de rapport

Project ID: QLK3-CT-2000-00103
Financé au titre de: FP5-LIFE QUALITY
Pays: United Kingdom

Cloning of sulfate transporter genes

Two sulfate transporter genes were cloned as part of this project. ZmST1;1 (Zea mays: ZmST1;1, AF355602) and StST1;1 (Solanum tuberosum: StST1, AF309643) from maize and potato respectively are members of group 1, generally considered to be high affinity transporters, principally responsible for uptake in the roots. Expression of these was analysed in respect to sulfur nutrition. A transcriptional repression at high sulfur availability was noted. A strategy to enhance sulfur flux into plants is the over-expression of the transporter responsible for initial sulfate uptake: StST1;1 in potato and ZmST1;1 in maize. This was attempted using the pRCg2promoter in maize and the pRIAGS promoter in potato. Both of these promoters are expressed in roots as shown with reporter genes.

The use of these promoters circumvents endogenous controls of transcription as seen in these species. A wheat TtST1;1 genes was expressed in maize (this could be distinguished from endogenous maize ST expression whilst the native StST1;1 genes was over-expressed in potato (expression could still be distinguished using appropriate primer combinations centred on the cloning sites). Confirmation of expression of the transgenes was obtained by RT-PCR. To further enhance sulfur accumulation, a suitable sink was required. Double transformants were produced containing both the zein sulfur-rich storage protein and the StST1;1 transporter. These various transgenic lines will be analysed in the future.

Informations connexes


Malcolm HAWKESFORD, (head of research programme)
Tél.: +44-1582-763133
Fax: +44-1582-763010