文章基本信息

标题：Functional characterization of the principal sigma factor RpoD of phytoplasmas via an in vitro transcription assay
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作者：Chihiro Miura ; Ken Komatsu ; Kensaku Maejima 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
期号：1
DOI：10.1038/srep11893
语种：English
出版社：Springer Nature
摘要：Phytoplasmas (class, Mollicutes ) are insect-transmissible and plant-pathogenic bacteria that multiply intracellularly in both plants and insects through host switching. Our previous study revealed that phytoplasmal sigma factor rpoD of OY-M strain ( rpoD _OY) could be a key regulator of host switching, because the expression level of rpoD _OY was higher in insect hosts than in plant hosts. In this study, we developed an in vitro transcription assay system to identify RpoD_OY-dependent genes and the consensus promoter elements. The assay revealed that RpoD_OY regulated some housekeeping, virulence, and host–phytoplasma interaction genes of OY-M strain. The upstream region of the transcription start sites of these genes contained conserved –35 and –10 promoter sequences, which were similar to the typical bacterial RpoD-dependent promoter elements, while the –35 promoter elements were variable. In addition, we searched putative RpoD-dependent genes based on these promoter elements on the whole genome sequence of phytoplasmas using in silico tools. The phytoplasmal RpoD seems to mediate the transcription of not only many housekeeping genes as the principal sigma factor, but also the virulence- and host-phytoplasma interaction-related genes exhibiting host-specific expression patterns. These results indicate that more complex mechanisms exist than previously thought regarding gene regulation enabling phytoplasmas to switch hosts.