Pseudomonads contribute to regulation of Pratylenchus penetrans (Nematoda) populations on apple

• Published in: Canadian journal of microbiology Vol. 64; no. 11; pp. 775 - 785
• Main Authors: Watson, Tristan T, Forge, Tom A, Nelson, Louise M
• Format: Journal Article
• Language: English
• Published: Canada NRC Research Press 01.11.2018; Canadian Science Publishing NRC Research Press
• Subjects: Animals; apple; Apples; biocontrol; Biomass; Colonization; contrôle biologique; enzyme activity; Fruits; Fungi; growth promotion; Inoculation; maladie de la replantation; Malus - microbiology; Malus domestica; Microbiology; Microorganisms; Nematoda - growth & development; Nematode Infections - parasitology; Nematode Infections - prevention & control; orchard soils; Orchards; Pathogens; Pest Control - methods; phytomass; Plant biomass; Plant Diseases - parasitology; Plant Diseases - prevention & control; Plant growth; pomme; Populations; Pratylenchus penetrans; Protease; Proteinase; proteinases; Prunus avium; Pseudomonas fluorescens; Pseudomonas fluorescens - physiology; Pseudomonas spp; Replant disease; Rhizosphere; roots; screening; Seedlings; Semifabricated products; Soil Microbiology; Soil microorganisms; Soils; Pratylenchus penetrans; apple; Pseudomonas spp; contrôle biologique; maladie de la replantation; pomme; replant disease; biocontrol
• ISSN: 0008-4166; 1480-3275; 1480-3275
• DOI: 10.1139/cjm-2018-0040

Inoculation with antagonistic soil microorganisms has shown potential to suppress replant disease of apple in orchard soils. Pseudomonas spp. may have the potential to reduce Pratylenchus penetrans populations on apple. Pseudomonas spp. were isolated from the rhizosphere of sweet cherry and screened for antagonistic characteristics. Two highly antagonistic Pseudomonas isolates, P10-32 and P10-42, were evaluated for growth promotion of apple seedlings, suppression of P. penetrans populations, and root colonization in soil from three orchards. During the isolate screening, Pseudomonas fluorescens P10-32 reduced in vitro growth of fungal pathogens, had protease activity, had capacity to produce pyrrolnitrin, suppressed P. penetrans populations, and increased plant biomass. Pseudomonas fluorescens P10-42 reduced in vitro growth of fungal pathogens, had protease activity, suppressed P. penetrans populations, and increased plant biomass. In potted orchard soil, inoculating apple with P. fluorescens P10-32 suppressed P. penetrans populations in one of the three soils examined. Inoculation with P. fluorescens P10-42 improved plant growth in two of the soils and suppressed P. penetrans abundance in one soil. In one of the soils, P. fluorescens P10-42 was detected on the roots 56 days postinoculation. Overall, we conclude that Pseudomonas spp. play a role in suppressing P. penetrans on apple in orchard soil.