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

• Published in: Current biology Vol. 24; no. 11; pp. 1216 - 1221
• Main Authors: Casson, Stuart A., Hetherington, Alistair M.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 02.06.2014; Cell Press
• Subjects: Agrobacterium tumefaciens - genetics; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cell Differentiation - radiation effects; Light; Luminescent Proteins - genetics; Luminescent Proteins - metabolism; Mesophyll Cells - metabolism; Mesophyll Cells - radiation effects; Organ Specificity; Phloem - growth & development; Phloem - metabolism; Phloem - radiation effects; Phytochrome B - genetics; Phytochrome B - metabolism; Plant Leaves - growth & development; Plant Leaves - metabolism; Plant Leaves - radiation effects; Plant Stomata - growth & development; Plant Stomata - metabolism; Plant Stomata - radiation effects; Recombinant Proteins - genetics; Recombinant Proteins - metabolism
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2014.03.074

Stomata are pores found on the surfaces of leaves, and they regulate gas exchange between the plant and the environment [1]. Stomatal development is highly plastic and is influenced by environmental signals [2]. Light stimulates stomatal development, and this response is mediated by plant photoreceptors [3–5], with the red-light photoreceptor phytochrome B (phyB) having a dominant role in white light [3]. Light also regulates stomatal development systemically, with the irradiance perceived by mature leaves modulating stomatal development in young leaves [6, 7]. 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 [8], 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. •phyB is required during the light-mediated systemic control of stomatal development•Light-mediated stomatal development does not require phyB expression in the epidermis•PHYB expression in mature phyB-9 leaves rescues stomatal development in young leaves•phyB-9 mutants are defective in light-mediated systemic stomatal development Stomatal development is regulated by light, which requires the red-light photoreceptor phytochrome B. By using both tissue-specific and inducible phyB expression, Casson and Hetherington show that phyB acts both within the stomatal lineage and systemically to regulate stomatal development.