|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<i> Colletotrichum acutatum, </i>is the mayor fungal disease of lupin worldwide<i>. </i>The main infection way is contaminated seed. <i>Bacillus </i>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 <i>Bacillus </i>spp. to control anthracnose on Andean lupin seed (<i>Lupinus mutabilis</i>). Antifungal activity of living cells and cell free compounds from several <i>Bacillus </i>strains against <i>C. acutatum </i>was evaluated. Strains that showed the highest <i>C. acutatum</i> 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 2×10<sup>8 </sup>CFU mL<sup>-1</sup> and pathogen at 2×10<sup>6 </sup>conidia mL<sup>-1</sup>. Antifungal activity assay showed that living cells and cell free compounds from four <i>Bacillus </i>spp. strains inhibited <i>C. acutatum </i>micelial growth up to 78.0% and 100%, respectively. TLC–bioautography analysis showed that lipopeptide fractions corresponding to fengycins and iturins from each <i>Bacillus</i> strain have strongly antifungal activity against <i>C. acutatum</i>. Bacteria treatments significantly reduced anthracnose incidence from 94% (untreated control) to 0%. These results suggest that <i>Bacillus </i>spp. strains are potential agents to control anthracnose infection on Andean lupin seed.