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phytochrome B Is Required for Light-Mediated Systemic Control of Stomatal Development

2014; Elsevier BV; Volume: 24; Issue: 11 Linguagem: Inglês

10.1016/j.cub.2014.03.074

1879-0445

Stuart A. Casson, Alistair M. Hetherington,

Photosynthetic Processes and Mechanisms

Stomata are pores found on the surfaces of leaves, and they regulate gas exchange between the plant and the environment [1Hetherington A.M. Woodward F.I. The role of stomata in sensing and driving environmental change.Nature. 2003; 424: 901-908Crossref PubMed Scopus (1528) Google Scholar]. Stomatal development is highly plastic and is influenced by environmental signals [2Casson S. Gray J.E. Influence of environmental factors on stomatal development.New Phytol. 2008; 178: 9-23Crossref PubMed Scopus (255) Google Scholar]. Light stimulates stomatal development, and this response is mediated by plant photoreceptors [3Casson S.A. Franklin K.A. Gray J.E. Grierson C.S. Whitelam G.C. Hetherington A.M. Phytochrome B and PIF4 regulate stomatal development in response to light quantity.Curr. Biol. 2009; 19: 229-234Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar, 4Boccalandro H.E. Rugnone M.L. Moreno J.E. Ploschuk E.L. Serna L. Yanovsky M.J. Casal J.J. Phytochrome B enhances photosynthesis at the expense of water-use efficiency in Arabidopsis.Plant Physiol. 2009; 150: 1083-1092Crossref PubMed Scopus (145) Google Scholar, 5Kang C.Y. Lian H.L. Wang F.F. Huang J.R. Yang H.Q. Cryptochromes, phytochromes, and COP1 regulate light-controlled stomatal development in Arabidopsis.Plant Cell. 2009; 21: 2624-2641Crossref PubMed Scopus (210) Google Scholar], with the red-light photoreceptor phytochrome B (phyB) having a dominant role in white light [3Casson S.A. Franklin K.A. Gray J.E. Grierson C.S. Whitelam G.C. Hetherington A.M. Phytochrome B and PIF4 regulate stomatal development in response to light quantity.Curr. Biol. 2009; 19: 229-234Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar]. Light also regulates stomatal development systemically, with the irradiance perceived by mature leaves modulating stomatal development in young leaves [6Lake J.A. Quick W.P. Beerling D.J. Woodward F.I. Plant development. Signals from mature to new leaves.Nature. 2001; 411: 154Crossref PubMed Scopus (316) Google Scholar, 7Thomas P.W. Woodward F.I. Quick P.W. Systemic irradiance signalling in tobacco.New Phytol. 2003; 161: 193-198Crossref Scopus (104) Google Scholar]. Here, we show that phyB is required for this systemic response. Using a combination of tissue-specific expression and an inducible expression system in the loss-of-function phyB-9 mutant [8Reed J.W. Nagpal P. Poole D.S. Furuya M. Chory J. Mutations in the gene for the red/far-red light receptor phytochrome B alter cell elongation and physiological responses throughout Arabidopsis development.Plant Cell. 1993; 5: 147-157Crossref PubMed Scopus (766) Google Scholar], we show that phyB expression in the stomatal lineage, mesophyll, and phloem is sufficient to restore wild-type stomatal development. Induction of PHYB in mature leaves also rescues stomatal development in young untreated leaves, whereas phyB mutants are defective in the systemic regulation of stomatal development. Our data show that phyB acts systemically to regulate cell fate decisions in the leaf epidermis.