RESEARCH REPORTS FROM INSTITUTE FOR AGRO-MICROBIOLOGY, Vol. 3, 1999 p.79-86
Copyright © Institute for Agro-Microbiology. All Rights Reserved.

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GRANT REPORT

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7.Analysis of the Genes Confering on Colonization of Bacteria on Plants

Yuichi Takikawa, Takashi Kumakura, Yuikiko Imanishi and Yasuhiro Inoue(Faculty of Agriculture, Shizuoka University)

Some of the pathogenicity related genes of plant pathogenic bacteria have been suggested as playing a role on their growth and survival on plants. A strain of Pseudomonas fluorescens, a saprophytic, root-colonizing bio-control agent against bacterial wilt of tomato was demonstrated to have DNA regions homologous to hrp genes of P. syringae plant pathogens. We constructed a DNA library of the P. fluorescens strain and selected clones harbouring the homologous DNA regions from the library. They were subcloned and sequenced. The result demonstrated that the P. fluorescens strain conserved long area of deduced hrp gene cluster homologous to that of P. syringae in terms of their relative positions and directions. The significant differences were observed when P. fluorescens genome was shown to lack hrpZ and hrpA genes, of which the products are known to serve as an elicitor and an injecting apparatus hrp pilus, respectively. It was suggested that the deletion of these genes might be the cause of keeping the P. fluorescens strain as a non-pathogenic saprophyte and that other hrp genes may be involved in survival and growth of the bacterium.

キーワード／Keywords
Pseudomonas fluorescens、hrp遺伝子／hrp genes、定着能力／epiphytic fitness、生物防除／biological control