Disruption of ROOT PHOTOTROPISM2 gene does not affect phototropin-mediated stomatal opening.
Phototropins (phot1 and phot2), blue light-receptor protein kinases in plants, mediate stomatal opening by activating the plasma membrane H(+)-ATPase in guard cells, but the signaling from phototropins to the H(+)-ATPase remains unknown. A recent study concluded that ROOT PHOTOTROPISM2 (RPT2) is involved in the primary step of this process. However, this conclusion is based solely on the determination of stomatal apertures in the epidermis. We investigated the role of RPT2 in blue light-dependent stomatal opening in more detail. We generated double mutants of rpt2 and phototropins (phot1 or phot2) in the Col ecotype background and obtained the typical phenotypes of rpt2 mutants, including the impairment in phototropism. In contrast, neither blue light-dependent H(+) pumping nor blue light-dependent H(+)-ATPase activation in guard cells was affected in the rpt2 mutants of rpt2, phot1 rpt2, and phot2 rpt2. Stomata in these rpt2 mutants opened widely by blue light in both epidermal peels and intact leaves, and no difference in the responses was found between the wild type and the mutants. From these results, we concluded that RPT2 gene disruption does not affect blue light-dependent stomatal opening.
Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan.
Toshifumi
T
Tsutsumi
Atsushi
A
Takemiya
Akiko
A
Harada
Ken-ichiro
K
Shimazaki
D048948:14-3-3 Proteins / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D003116:Color; D060146:Ecotype; D017343:Genes, Plant; D006859:Hydrogen / Q000378:metabolism; D008027:Light; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D018524:Phototropism; D019441:Plant Epidermis / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D054046:Plant Stomata / Q000235:genetics / Q000378:metabolism / Q000502:physiology* / Q000528:radiation effects; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D006180:Proton-Translocating ATPases / Q000378:metabolism; D011523:Protoplasts / Q000166:cytology / Q000378:metabolism
D048948:14-3-3 Proteins; D029681:Arabidopsis Proteins; C423903:PHOT2 protein, Arabidopsis; D010750:Phosphoproteins; C405209:RPT2 protein, Arabidopsis; D006859:Hydrogen; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D006180:Proton-Translocating ATPases