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Control of Gibberellin Levels and Gene Expression during De-Etiolation in Pea


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Reid, JB, Botwright, NA, Smith, JJ, O'Neill, DP and Kerckhoffs, LHJ 2002 , 'Control of Gibberellin Levels and Gene Expression during De-Etiolation in Pea' , Plant Physiology, vol. 128, no. 2 , pp. 734-741 .

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Gibberellin Al (GAl) levels drop significantly in wild-type pea (Pisum sativum) plants within 4 h of exposure to red, blue, or far-red light. This response is controlled by phytochrome A (phyA) (and not phyB) and a blue light receptor. GAs levels are increased in response to 4 h of red light, whereas the levels of GA19, GA2o, and GA29 do not vary substantially. Red light appears to control GAl levels by down-regulating the expression of Mendel's LE (PsGA30xl) gene that controls the conversion of GA20 to GAl' and by up-regulating PsGA2ox2, which codes for a GA 2-oxidase that converts GAl to GAs. This occurs within 0.5 to 1 h of exposure to red light. Similar responses occur in blue light. The major GA 20-oxidase gene expressed in shoots, PsGA20oxl, does not show substantial light regulation, but does show up-regulation after 4 h of red light, probably as a result of feedback regulation. Expression of PsGA30xl shows a similar feedback response, whereas PsGA2ox2 shows a feed-forward response. These results add to our understanding of how light reduces shoot elongation during de-etiolation.

Item Type: Article
Authors/Creators:Reid, JB and Botwright, NA and Smith, JJ and O'Neill, DP and Kerckhoffs, LHJ
Journal or Publication Title: Plant Physiology
ISSN: 0032-0889
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