Hoshi Ayaka, Oshima Kenro, Kakizawa Shigeyuki, Ishii Yoshiko, Ozeki Johji, Hashimoto Masayoshi, Komatsu Ken, Kagiwada Satoshi, Yamaji Yasuyuki, Namba Shigetou
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.
Proc Natl Acad Sci U S A. 2009 Apr 14;106(15):6416-21. doi: 10.1073/pnas.0813038106. Epub 2009 Mar 27.
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.
农业科学中最重要的主题之一是鉴定参与植物病害的毒力因子。在此，我们表明单一毒力因子天草素诱导剂（TENGU）可诱发扫帚状丛生和矮化，并且是植物致病细菌植原体的一种小分泌蛋白。当TENGU在本氏烟草植株中表达时，这些植株表现出扫帚状丛生和矮化症状，这是植原体感染的典型症状。表达TENGU的转基因拟南芥株系表现出类似症状，证实了TENGU表达对植物的影响。尽管植原体的定位局限于韧皮部，但通过免疫组织化学分析在顶芽中检测到了TENGU蛋白，这表明TENGU从韧皮部转运到了其他细胞。微阵列分析表明，与GUS转基因对照植株相比，TENGU转基因植株中生长素响应基因显著下调。这些结果表明，TENGU抑制生长素相关途径，从而影响植物发育。
