HCS Fall 2015 Seminar Series

Characterization of Pseudomonas for biocontrol of plant-parasitic nematodes
DECEMBER 2, 2015

11:30 – 12:25  PM

Video link 244 Kottman Hall and 121 Fisher Auditorium

 

Christopher G. Taylor

Associate Professor, Molecular Genetics, Nematology

Department of Plant Pathology, and

Center for Applied Plant Sciences

OSU/OARDC

 

Abstract:  Plant-parasitic nematodes are among the most destructive plant pests, causing substantial economic losses to agronomic crops worldwide. Current methods of using bacteria as biocontrol agents for plant-parasitic nematodes have met with limited success in part due to limited knowledge about mechanisms of biocontrol and biotic factors that are important to rhizosphere persistence. Using a C. elegans bioassay we have screened over 12,000 bacterial isolates from a variety of natural sources (water, soil, roots) and  identified over 50 different isolates of Pseudomonas that interfere with nematode growth and development. Several of these strains also showed in planta activity against the soybean cyst nematode, Heterodera glycines.  Over half of the Pseudomonas strains also exhibited activity in plate and soil assays against other plant-pathogenic fungi, oomyctes and bacteria. Genome sequence analysis of all 50+ strains reveal the presence of many genes that are potentially involved in biocontrol activity including the production of antibiotics, siderophores, hydrogen cyanide (HCN), polysaccharides, and exoproteases. In several Pseudomonas strains we used both random and targeted mutagenesis to identify non-nematode lethal mutants. Testing of the non-lethal isolates for HCN showed significant reduction in HCN production. Loss of HCN production in the Pseudomonas was correlated with reduced capacity to protect plants from plant-parasitic nematodes. Our data indicate that HCN is potentially an important compound produced by pseudomonads within the rhizosphere with antagonist activity toward plant-parasitic nematodes and as a possible regulator of root development, ethylene production and metabolism of the host plant.

Contact:  taylor.1886@osu.edu; phone (330) 263-3847;  210 Selby Hall, OARDC, 1680 Madison Ave., Wooster, OH 44691; plantpath.osu.edu, and caps.osu.edu.