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First published online October 21, 2005; 10.1104/pp.105.067462 Plant Physiology 139:1472-1482 (2005) © 2005 American Society of Plant Biologists Cryptochrome 1 Contributes to Blue-Light Sensing in Pea1School of Plant Science, University of Tasmania, Hobart, Tasmania 7001, Australia
Cryptochromes are widespread in higher plants but their physiological roles as blue-light photoreceptors have been examined in relatively few species. Screening in a phyA null mutant background has identified several blue-light response mutants in pea (Pisum sativum), including one that carries a substitution of a highly conserved glycine residue in the N-terminal photolyase-homologous domain of the pea CRY1 gene. Analyses of cry1, phyA, and phyB mutants show that all three photoreceptors contribute to seedling photomorphogenesis under high-irradiance blue light, whereas phyA is the main photoreceptor active under low irradiances. Triple phyA phyB cry1 mutants grown under high-irradiance blue light are indistinguishable from dark-grown wild-type plants in length and leaf expansion but show a small residual response to higher-irradiance white light. Monogenic cry1 mutants have little discernable phenotype at the seedling stage, but later in development are more elongated than wild-type plants. In addition, the loss of cry1 moderates the short-internode phenotype of older phyA mutants, suggesting an antagonism between phyA and cry1 under some conditions. Pea cry1 has a small inhibitory effect on flowering under long and short days. However, the phyA cry1 double mutant retains a clear promotion of flowering in response to blue-light photoperiod extensions, indicating a role for one or more additional blue-light photoreceptors in the control of flowering in pea.
1 This work was supported by the Australian Research Council through Large Grant A00105316 and Discovery Project DP044972 (to J.B.R. and J.L.W.), and an Australian Postgraduate Award (to J.D.P.). 2 Present address: Commonwealth Scientific and Industrial Research Organization, Plant Industries, G.P.O. Box 1600, Canberra, ACT 2601, Australia. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: James L. Weller (jim.weller{at}utas.edu.au). Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.067462. * Corresponding author; e-mail jim.weller{at}utas.edu.au; fax 61362262986. Received June 28, 2005; returned for revision September 8, 2005; accepted September 8, 2005. This article has been cited by other articles:
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