Bacterial selection for biological control of plant disease: criterion determination and validation

Abstract

This study aimed to evaluate the biocontrol potential of bacteria isolated from different plant species and soils. The production of compounds related to phytopathogen biocontrol and/or promotion of plant growth in bacterial isolates was evaluated by measuring the production of antimicrobial compounds (ammonia and antibiosis) and hydrolytic enzymes (amylases, lipases, proteases, and chitinases) and phosphate solubilization. Of the 1219 bacterial isolates, 92% produced one or more of the eight compounds evaluated, but only 1% of the isolates produced all the compounds. Proteolytic activity was most frequently observed among the bacterial isolates. Among the compounds which often determine the success of biocontrol, 43% produced compounds which inhibit mycelial growth of Monilinia fructicola, but only 11% hydrolyzed chitin. Bacteria from different plant species (rhizosphere or phylloplane) exhibited differences in the ability to produce the compounds evaluated. Most bacterial isolates with biocontrol potential were isolated from rhizospheric soil. The most efficient bacteria (producing at least five compounds related to phytopathogen biocontrol and/or plant growth), 86 in total, were evaluated for their biocontrol potential by observing their ability to kill juvenile Mesocriconema xenoplax. Thus, we clearly observed that bacteria that produced more compounds related to phytopathogen biocontrol and/or plant growth had a higher efficacy for nematode biocontrol, which validated the selection strategy used.

Biocontrol of Bacterial Wilt Disease Through Complex Interaction Between Tomato Plant, Antagonists, the Indigenous Rhizosphere Microbiota, and Ralstonia solanacearum

“…The phz gene, encoding phenazine production, might also play a role in R. solanacearum control (Hariprasad et al, 2014). Recently, a selection strategy of potential antagonists based on the number of biological control and/or plant growth promoting related function per inoculant candidate was proposed by Mota et al (2017). They have shown a positive correlation between the number of in vitro functions per antagonist and their effects on the pathogen.…”

Biological control of Pseudomonas syringae pv. garcae in coffee crop with Bacillus spp. isolates

“…Ammonia, siderophores, and hydrocyanic acid syntheses by bacterial isolates have been used as criteria for choosing potential plant disease biocontrol agents and/or plant growth promoters (Mota et al, 2017;Radhakrishnan et al, 2017;Santiago et al, 2015;Ramette et al, 2003).…”

Screening, Identification, and Optimization of Fermentation Conditions of an Antagonistic Endophyte to Wheat Head Blight

“…a large number of studies have shown that endophytic bacteria are correlated with enhanced plant growth under both abiotic (heat, drought, salinity, heavy metal exposure, etc.) and biotic stresses, including Fusarium head blight [8][9][10]. For example, Comby et al [8] isolated 86 microorganisms from wheat plants to find endophytes with the potential to become biological control agents against FHB, and 13 strains conferred significant protection against FHB on wheat spikelets.…”