Phototropin from Chlamydomonas reinhardtii is functional in Arabidopsis thaliana.
Phototropin, a plant blue light photoreceptor, mediates important blue light responses such as phototropism, chloroplast positioning and stomatal opening in higher plants. In Arabidopsis thaliana, two phototoropins, phototropin 1 and 2, are known. Recently, in the unicellular green alga, Chlamydomonas reinhardtii, a phototropin homolog was identified. It exhibits photochemical properties similar to those of higher plant phototropins and is involved in multiple steps of the sexual life cycle of Chlamydomonas. Here, we expressed Chlamydomonas phototropin in Arabidopsis to examine whether it is active in a distantly related plant species. The Arabidopsis mutant deficient in both phototropin 1 and 2 was transformed with a vector containing Chlamydomonas phototropin cDNA fused to a cauliflower mosaic virus 35S promoter. The resulting lines were classified into high, medium and low expressers based on RNA gel blot and immunoblot analyses. Typical phototropin responses were restored in high expression lines. These results demonstrate that Chlamydomonas phototropin is functional in higher plants. Hence, the basic mechanism of phototropin action is highly conserved, even though its apparent physiological functions are quite diverse.
Onodera
Akihiko
A
Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo-Ku, Kyoto, 606-8502 Japan.
Kong
Sam-Geun
SG
Doi
Michio
M
Shimazaki
Ken-Ichiro
K
Christie
John
J
Mochizuki
Nobuyoshi
N
Nagatani
Akira
A
D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins; D016825:Chlamydomonas reinhardtii / Q000235:genetics*; D002736:Chloroplasts / Q000502:physiology; D056931:Cryptochromes; D005420:Flavoproteins / Q000235:genetics* / Q000378:metabolism*; D007246:Infertility; D008027:Light; D010641:Phenotype; D018524:Phototropism / Q000235:genetics*; D018515:Plant Leaves / Q000502:physiology; D030821:Plants, Genetically Modified; D015398:Signal Transduction / Q000502:physiology
D029681:Arabidopsis Proteins; C538962:CRY1 protein, Arabidopsis; D056931:Cryptochromes; D005420:Flavoproteins