Resistance of cucumber seedlings to Colletotrichum lagenarium induced by fractions of Saccharomyces cerevisiae extract

Abstract

The objective of this work was to purify the Saccharomyces Cerevisiae extract fractions that induce resistance to Colletorichum lagenarium in cucumber and to determine their efficiency in protecting seedlings in the greenhouse. Yeast cell suspension, its crude aqueous extract autoclaved for 4 and 10 hours, two fractions (supernatant and pellet) resulting from ethanolic precipitation of the crude extract (4 hours) and the supernatant fractions identified in anion exchange chromatography were sprayed onto cucumber cotyledons. The yeast cell suspension did not significantly control the disease. The autoclaved crude extracts reduced the anthracnose severity between 82 and 86%, and the ethanolic precipitation fractions in 98%. The supernatant fractions non-adsorbed (chromatography peak I) and adsorbed (peak II) to DEAE-cellulose resin, containing mainly carbohydrates, were the most effective for inducing assistance to the seedlings, and reduced the anthracnose severity in 81 and 72% respectively. Autoclaving crude extracts of S. cerevisiae is necessary to extract molecules that elicit resistance to C. lagenarium in cucumber cotyledon.