title: Quantitative analyses on dynamic changes in the organization of host Arabidopsis thaliana actin microfilaments surrounding the infection organ of the powdery mildew fungus Golovinomyces orontii.
abstract: Obligate biotrophic fungi that cause powdery mildew on host plants form a specialized infection organ called the haustorium in the host apoplast. It was previously reported that the haustorium is surrounded by host actin microfilaments (AFs). The previous study used fixed cells, in which AFs were stained with fluorescently labeled phalloidine, therefore the structural dynamics of haustorium-surrounding AFs has not been examined. In the present study, we performed a live imaging analysis to examine the dynamics and developmental changes in the organization of haustorium-surrounding host AFs using host Arabidopsis thaliana and A. thaliana-adapted powdery mildew fungus Golovinomyces orontii. Image correlation-based velocimetry analysis suggested that AFs around haustorium are rather static compared to the dynamicity of AFs at the cell surface. Quantification of AF density and bundling showed that the density, but not the level of bundling, of haustorium-surrounding AFs increased as the haustorium matures. The possible role of AFs around haustoria is discussed.
authors.affiliation: The Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma-shi, Nara, 630-0192, Japan. noriko@bs.s.u-tokyo.ac.jp.|Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. noriko@bs.s.u-tokyo.ac.jp.
authors.forename: Noriko
authors.initials: N
authors.lastname: Inada
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8562, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Higaki
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8562, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Hasezawa
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D017360:Arabidopsis / Q000378:metabolism* / Q000382:microbiology*; D001203:Ascomycota / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000737:chemistry; D054884:Host-Pathogen Interactions; D010935:Plant Diseases / Q000382:microbiology*
chemical_list: D049452:Green Fluorescent Proteins
keywords: Actin microfilament; Arabidopsis thaliana; Golovinomyces orontii; Haustorium; Image analysis