title: A unique virulence factor for proliferation and dwarfism in plants identified from a phytopathogenic bacterium.
abstract: One of the most important themes in agricultural science is the identification of virulence factors involved in plant disease. Here, we show that a single virulence factor, tengu-su inducer (TENGU), induces witches' broom and dwarfism and is a small secreted protein of the plant-pathogenic bacterium, phytoplasma. When tengu was expressed in Nicotiana benthamiana plants, these plants showed symptoms of witches' broom and dwarfism, which are typical of phytoplasma infection. Transgenic Arabidopsis thaliana lines expressing tengu exhibited similar symptoms, confirming the effects of tengu expression on plants. Although the localization of phytoplasma was restricted to the phloem, TENGU protein was detected in apical buds by immunohistochemical analysis, suggesting that TENGU was transported from the phloem to other cells. Microarray analyses showed that auxin-responsive genes were significantly down-regulated in the tengu-transgenic plants compared with GUS-transgenic control plants. These results suggest that TENGU inhibits auxin-related pathways, thereby affecting plant development.
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Hoshi
authors.forename: Kenro
authors.initials: K
authors.lastname: Oshima
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kakizawa
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Ishii
authors.forename: Johji
authors.initials: J
authors.lastname: Ozeki
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Ken
authors.initials: K
authors.lastname: Komatsu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kagiwada
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamaji
authors.forename: Shigetou
authors.initials: S
authors.lastname: Namba