AUTHOR=Li Peng , Yin Wenfang , Yan Jinli , Chen Yufan , Fu Shuna , Song Shihao , Zhou Jianuan , Lyu Mingfa , Deng Yinyue , Zhang Lian-Hui 

TITLE=Modulation of Inter-kingdom Communication by PhcBSR Quorum Sensing System in Ralstonia solanacearum Phylotype I Strain GMI1000

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01172

DOI=10.3389/fmicb.2017.01172

ISSN=1664-302X

ABSTRACT=<p><italic>Ralstonia solanacearum</italic> is a ubiquitous soil-borne plant pathogenic bacterium, which frequently encounters and interacts with other soil cohabitants in competition for environmental niches. Ralsolamycin, which is encoded by the <italic>rmy</italic> genes, has been characterized as a novel inter-kingdom interaction signal that induces chlamydospore development in fungi. In this study, we provide the first genetic evidence that the <italic>rmy</italic> gene expression is controlled by the PhcBSR quorum sensing (QS) system in strain GMI1000. Mutation of <italic>phcB</italic> could lead to significant reduction of the expression levels of the genes involved in ralsolamycin biosynthesis. In addition, both the <italic>phcB</italic> and <italic>rmy</italic> mutants were attenuated in induction of chlamydospore formation in <italic>Fusarium oxysporum</italic> f. <italic>cubense</italic> and diminished in the ability to compete with the sugarcane pathogen <italic>Sporisorium scitamineum</italic>. Agreeable with the pattern of QS regulation, transcriptional expression analysis showed that the transcripts of the <italic>rmy</italic> genes were increased along with the increment of the bacterial population density. Taken together, the above findings provide new insights into the regulatory mechanisms that the QS system involves in governing the ralsolamycin inter-kingdom signaling system.</p>