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Oral Technical Session: Agents for Biological Control

94-O

Bacillus spp. evaluation to control anthracnose infection on Andean lupin seed (Lupinus mutabilis Sweet)
V. d. R. YÁNEZ-MENDIZÁBAL (1), C. E. Falconí (2), A. C. Grijalva (1)
(1) Universidad de las Américas, Quito, Ecuador; (2) Universidad de las Fuerzas Armadas -ESPE, Quito, Ecuador

Anthracnose, caused by Colletotrichum acutatum, is the mayor fungal disease of lupin worldwide. The main infection way is contaminated seed. Bacillus spp. efficacy, based on antifungal compounds production, has been demonstrated on a wide range of plant fungal pathogens. The objective of this study was to evaluate the potential of Bacillus spp. to control anthracnose on Andean lupin seed (Lupinus mutabilis). Antifungal activity of living cells and cell free compounds from several Bacillus strains against C. acutatum was evaluated. Strains that showed the highest C. acutatum inhibition were selected to evaluate for their lipopeptide antifungal activity by TLC–bioautography analysis and efficacy to control anthracnose artificial infection on seed. Bacterial treatments were prepared from 72-h-old cultures at 2×108 CFU mL-1 and pathogen at 2×106 conidia mL-1. Antifungal activity assay showed that living cells and cell free compounds from four Bacillus spp. strains inhibited C. acutatum micelial growth up to 78.0% and 100%, respectively. TLC–bioautography analysis showed that lipopeptide fractions corresponding to fengycins and iturins from each Bacillus strain have strongly antifungal activity against C. acutatum. Bacteria treatments significantly reduced anthracnose incidence from 94% (untreated control) to 0%. These results suggest that Bacillus spp. strains are potential agents to control anthracnose infection on Andean lupin seed.