Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 20, 2007
Publication Date: August 1, 2007
Citation: Fang, G.C., Wechter, W.P., Kluepfel, D.A. 2007. A BROAD-SPECTRUM ANTAGONISTIC ACTIVITY OF THE BIOCONTROL AGENT PSEUDOMONAS SYNXANTHA BG33R. American Phytopathological Society Abstracts. Technical Abstract: Pseudomonas synxantha strain BG33R was previously reported to be effective in controlling the Peach Tree Short Life (PTSL) syndrome by suppressing the ring nematode (Mesocriconema xenoplax) through terminating the eggs of the second juvenile stage from further development. In this research the spectrum of the antimicrobial activity of the BG33R was further explored by testing its effect on other phytopathogenic organisms, including oomycetes, fungus, and insect. Surprisingly, the antagonistic activity of BG33R spanned highly diverse taxa. The cell-free culture filtrate of BG33R abolished the development of sporangia, disintegrated the zoospores within one minute of contact, and partially protected Arabidopsis from infection by Phytophthora nicotianae. It also suppressed the vegetative growth and appressorium formation of an important phytopathogenic fungus Magnaporthe grisea. When injected into a major insect pest, Soybean looper (Pseudoplusia includens (Walker)), it killed the caterpillars within 48 hr. The accessible of fast surface motility suggests an aggressive colonization of the organism in the rhizosphere. The unusually broad spectrum of the antagonistic activity and the high stability of the BG33R suggest a great potential for the biocontrol application of this organism. Possible molecular mechanism involved in the regulation of the antibiotic activity will be discussed.