title: Functional characterization of blue-light-induced responses and PHOTOTROPIN 1 gene in Welwitschia mirabilis.
abstract: The blue light (BL) receptor phototropin (phot) is specifically found in green plants; it regulates various BL-induced responses such as phototropism, chloroplast movement, stomatal opening, and leaf flattening. In Arabidopsis thaliana, two phototropins--phot1 and phot2--respond to blue light in overlapping but distinct ways. These BL-receptor-mediated responses enhance the photosynthetic activity of plants under weak light and minimize photodamage under strong light conditions. Welwitschia mirabilis Hook.f. found in the Namib Desert, and it has adapted to severe environmental stresses such as limiting water and strong sunlight. Although the plant has physiologically and ecologically unique features, it is unknown whether phototropin is functional in this plant. In this study, we assessed the functioning of phot-mediated BL responses in W. mirabilis. BL-dependent phototropism and stomatal opening was observed but light-dependent chloroplast movement was not detected. We performed a functional analysis of the PHOT1 gene of W. mirabilis, WmPHOT1, in Arabidopsis thaliana. We generated transgenic A. thaliana lines expressing WmPHOT1 in a phot1 phot2 double mutant background. Several Wmphot1 transgenic plants showed normal growth, although phot1 phot2 double mutant plants showed stunted growth. Furthermore, Wmphot1 transgenic plants showed normal phot1-mediated responses including phototropism, chloroplast accumulation, stomatal opening, and leaf flattening, but lacked the chloroplast avoidance response that is specifically mediated by phot2. Thus, our findings indicate that W. mirabilis possesses typical phot-mediated BL responses that were at least partially mediated by functional phototropin 1, an ortholog of Atphot1.
authors: Department of Forest Environmental Sciences, Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan.
authors: Kazuhiro
authors: K
authors: Ishishita
authors: Department of Biology, Faculty of Science, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan.|Department of Plant Gene and Totipotency, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
authors: Noriyuki
authors: N
authors: Suetsugu
authors: Department of Forest Environmental Sciences, Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan.
authors: Yuki
authors: Y
authors: Hirose
authors: Department of Biology, Faculty of Science, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan.|Department of Plant Gene and Totipotency, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
authors: Takeshi
authors: T
authors: Higa
authors: Faculty of Art and Science, Kyushu University, Motooka, Fukuoka, 819-0395, Japan.
authors: Michio
authors: M
authors: Doi
authors: Department of Biology, Faculty of Science, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan.|Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan.
authors: Masamitsu
authors: M
authors: Wada
authors: Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan.|PRESTO, JST, Saitama, 332-0012, Japan.
authors: Tomonao
authors: T
authors: Matsushita
authors: Department of Forest Environmental Sciences, Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan. eiji.gotoh@agr.kyushu-u.ac.jp.
authors: Eiji
authors: E
authors: Gotoh
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D035682:Gnetophyta / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D055537:Light Signal Transduction; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010788:Photosynthesis / Q000528:radiation effects; D056949:Phototropins / Q000235:genetics / Q000378:metabolism*; D018524:Phototropism / Q000528:radiation effects; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases; D036226:Seedlings / Q000235:genetics / Q000502:physiology / Q000528:radiation effects
chemical_list: D029681:Arabidopsis Proteins; C423903:PHOT2 protein, Arabidopsis; D010750:Phosphoproteins; D056949:Phototropins; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: Blue light; Chloroplast movement; Phototropin; Phototropism; Stomatal opening; Welwitschia mirabilis