Enhancement of pulse crops: influence of novel rhizobacteria on the interaction of pea, lentil, and pathogenic fungi

Non-Peer ReviewedIn Saskatchewan, land area used to grow pulse crops (pea, lentil, bean, and chickpea) is increasing every year; between 2000 and 2001, an increase of 20% was recorded. Maintenance of plant health is imperative to produce an economically viable resource. The objective of this study is to characterize novel rhizobacteria for plant growth promoting properties: enhancing the development of pea and lentil plants, and suppressing the growth and disease severity caused by phytopathogenic fungi. Rhizobacterial isolates were selected from a preliminary group of 580 based on the ability to suppress Pythium, Rhizoctonia, and Fusarium spp. In in vitro assays, no one isolate, except for isolate 5-6, had shown the ability to strongly suppress all three pathogenic fungi. Additionally, the presence of pea or lentil seeds affected the ability of the strains to suppress the fungi. Bacterial cellfree filtrate suppressed the growth of Pythium and Rhizoctonia spp., thus fungal suppression is mediated by antifungal metabolites. Furthermore, suppression of Rhizoctonia sp. is correlated to the production of proteolytic enzymes by the rhizobacteria. Plant growth promoting rhizobacteria (PGPR) are important in food production by increasing crop productivity, and reducing crop losses caused by soil-borne phytopathogens