Physiological and molecular characterization of compost bacteria antagonistic to soil-borne plant pathogens.
Disease suppressive composts have the potential to mitigate the risks associated with chemical pesticides. One of the main characteristics responsible for the suppressive nature of composts is their microbiological populations. To gain insight into the determinants responsible for their suppressive effects, we assayed composts to (i) isolate and identify beneficial antagonistic bacteria, (ii) quantify their antifungal and anti-oomycetal activities, (iii) extract inhibitory compounds produced by the bacteria, and (iv) identify antimicrobial lipopeptides produced by these bacteria. The antagonistic bacteria belonged to the genera Arthrobacter, Pseudomonas, Bacillus, Brevibacillus, Paenibacillus, and Rummeliibacillus and had the ability to antagonise the growth of Fusarium sambucinum, Verticillium dahliae, and (or) Pythium sulcatum. These bacteria produced antimicrobial compounds that affected the mycelial growth and (or) conidial germination of the pathogens. Mass spectrometry analyses showed the presence of various antimicrobial lipopeptides in Bacillus and Bacillus-related spp. extracts, demonstrating that they are responsible, at least in part, for the antagonistic activity of the bacteria. Results from this work provide greater insight into some of the biological, biochemical, and physiological determinants of suppressiveness in composts involved in the control of plant pathogens.
a Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
Rowida
R
Mohamed
a Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
Emma
E
Groulx
a Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
Stefanie
S
Defilippi
a Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
Tamara
T
Erak
b Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0C6, Canada.
James T
JT
Tambong
c Centre de recherche en innovation sur les végétaux, Université Laval, Québec, QC G1V 0A6, Canada.
Russell J
RJ
Tweddell
a Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
Apollinaire
A
Tsopmo
a Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
Tyler J
TJ
Avis
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology; D001407:Bacillus / Q000737:chemistry / Q000502:physiology; D005670:Fusarium / Q000737:chemistry / Q000502:physiology; D018525:Germination; D055666:Lipopeptides / Q000494:pharmacology; D010935:Plant Diseases / Q000382:microbiology*; D010944:Plants / Q000382:microbiology*; D011775:Pythium / Q000737:chemistry / Q000502:physiology; D012988:Soil Microbiology; D013172:Spores, Fungal; D020172:Verticillium / Q000737:chemistry / Q000502:physiology
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D055666:Lipopeptides
composts suppresseurs; fengycin; fengycine; iturin; iturine; lipopeptides; suppressive compost; surfactin; surfactine