title: Biocontrol activity of Paenibacillus polymyxa AC-1 against Pseudomonas syringae and its interaction with Arabidopsis thaliana.
abstract: Paenibacillus polymyxa AC-1 (AC-1) is a plant growth-promoting rhizobacterium (PGPR) that has been used as a soil inoculant for biocontrol of plant pathogenic fungi and to promote plant growth. In this study, we examine the effects of AC-1 on the bacterial phytopathogen Pseudomonas syringae and internal colonization of AC-1 by counting bacterial populations that colonize plants. AC-1 inhibited the growth of both P. syringae pv. tomato DC3000 (Pst) and P. syringae pv. tabaci (Pta) in a concentration-dependent manner in in vitro assays. Upon treatment of AC-1 dropping at root tip of axenically grown Arabidopsis, we found that most of the AC-1 was detected in interior of leaves of Arabidiopsis plants rather than roots after 5 days post infection, indicating systemic spreading of AC-1 occur. We examined further AC-1 colonization patterns in Arabidopsis mutants deficient in phytohormone signaling pathways. These results indicated that abscisic acid (ABA) and jasmonic acid (JA) signaling pathways positively and negatively contributed, respectively, to AC-1 colonization of leaves, whereas epiphytic accumulation of AC-1 around root tissues was not affected. This study shows that AC-1 is an effective biocontrol agent to suppress P. syringae growth, possibly owing to its colonization patterns as a leaf-inhabiting endophyte. The results showed in this work will help to expand our understanding of the mode of action of AC-1 as a biological control agent and consequently, its application in agriculture.
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute for Bioscience and Biotechnology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon 305-806, South Korea; Department of Biosystems and Bioengineering, University of Science and Technology, 217 Gajeong-Ro, Yuseong-Gu, Daejeon 305-350, South Korea. Electronic address: qltbsm@kribb.re.kr.
authors.forename: Chi Eun
authors.initials: CE
authors.lastname: Hong
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute for Bioscience and Biotechnology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon 305-806, South Korea; Department of Biosystems and Bioengineering, University of Science and Technology, 217 Gajeong-Ro, Yuseong-Gu, Daejeon 305-350, South Korea. Electronic address: sykwon@kribb.re.kr.
authors.forename: Suk Yoon
authors.initials: SY
authors.lastname: Kwon
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute for Bioscience and Biotechnology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon 305-806, South Korea; Department of Biosystems and Bioengineering, University of Science and Technology, 217 Gajeong-Ro, Yuseong-Gu, Daejeon 305-350, South Korea. Electronic address: jmpark@kribb.re.kr.
authors.forename: Jeong Mee
authors.initials: JM
authors.lastname: Park
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D003517:Cyclopentanes / Q000378:metabolism; D005856:Germ-Free Life; D018551:Solanum lycopersicum / Q000382:microbiology; D009154:Mutation; D054883:Oxylipins / Q000378:metabolism; D056507:Paenibacillus / Q000502:physiology*; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000382:microbiology / Q000517:prevention & control; D018515:Plant Leaves / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D044224:Pseudomonas syringae / Q000502:physiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction; D012988:Soil Microbiology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D012336:RNA, Ribosomal, 16S; C011006:jasmonic acid; D000040:Abscisic Acid
keywords: Antibacterial activity; Internal colonization; Paenibacillus polymyxa AC-1; Phytohormone signaling pathway