title: Antagonistic potential of Pseudomonas graminis 49M against Erwinia amylovora, the causal agent of fire blight.
abstract: In a previous study (Mikiciński et al. in Eur J Plant Pathol, doi: 10.1007/s10658-015-0837-y , 2015), we described the characterization of novel strain 49M of Pseudomonas graminis, isolated from the phyllosphere of apple trees in Poland showing a good protective activity against fire blight on different organs of host plants. We now report investigations to clarify the basis for this activity. Strain 49M was found to produce siderophores on a medium containing complex CAS-Fe(3+) and HDTMA, but was not able to produce N-acyl homoserine lactones (AHLs). Moreover, it formed a biofilm on polystyrene and polyvinyl chloride (PVC) surfaces. Strain 49M gave a positive reaction in PCR with primers complementary to gacA, the regulatory gene influencing the production of several secondary metabolites including antibiotics. The genes prnD (encoding pyrrolnitrin), pltC, pltB (pyoluteorin), phlD (2,4-diacetyl-phloroglucinol) and phzC as well as phzD (and their homologs phzF and phzA encoding phenazine), described for antagonistic fluorescent pseudomonads, however, were not detected. Research into the biotic relationship between strain 49M and Erwinia amylovora strain Ea659 on five microbiological media showed that this strain clearly inhibited the growth of the pathogen on King's B and nutrient agar with glycerol media, to a very small extent on nutrient agar with sucrose, and not at all on Luria-Bertani agar. On medium 925, strain 49M even stimulated E. amylovora growth. The addition of ferric chloride to King's B resulted in the loss of its inhibitory ability. Testing the survival of 49M in vitro showed its resistance to drought, greater than that of E. amylovora.
authors.affiliation: Research Institute of Horticulture, Konstytucji 3 Maja 1/3, 96-100, Skierniewice, Poland.
authors.forename: Artur
authors.initials: A
authors.lastname: Mikiciński
authors.affiliation: Research Institute of Horticulture, Konstytucji 3 Maja 1/3, 96-100, Skierniewice, Poland. Piotr.Sobiczewski@inhort.pl.
authors.forename: Piotr
authors.identifier: http://orcid.org/0000-0001-9925-3611
authors.initials: P
authors.lastname: Sobiczewski
authors.affiliation: Research Institute of Horticulture, Konstytucji 3 Maja 1/3, 96-100, Skierniewice, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Puławska
authors.affiliation: Research Institute of Horticulture, Konstytucji 3 Maja 1/3, 96-100, Skierniewice, Poland.
authors.forename: Eligio
authors.initials: E
authors.lastname: Malusa
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism; D000898:Antibiosis / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms / Q000254:growth & development; D061046:Biological Control Agents / Q000378:metabolism*; D017931:DNA Primers; D044084:Erwinia amylovora / Q000235:genetics / Q000254:growth & development*; D027845:Malus / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology*; D011044:Poland; D011137:Polystyrenes; D011143:Polyvinyl Chloride; D011549:Pseudomonas / Q000235:genetics / Q000254:growth & development*; D017262:Siderophores / Q000378:metabolism
chemical_list: D054742:Acyl-Butyrolactones; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D061046:Biological Control Agents; D017931:DNA Primers; C091100:GacA protein, Bacteria; D011137:Polystyrenes; D017262:Siderophores; D011143:Polyvinyl Chloride
keywords: AHL; Antagonistic bacteria; Antibiotic genes; Biofilm; Siderophores