Pseudozyma aphidis bio-active extract inhibit plant pathogens and activate induce resistance in tomato plants

The constant growth in the world population demands a constant increase in agricultural yields. One of the main ways to increase agricultural yields is by improving the control of pests and pathogens. Human health and environmental concerns regarding the traditional synthetic pesticides challenge the scientific community to discover new and less harmful ways to control pests, such as the development of biocontrol agents and natural-based pesticides. Previous studies have established that application of live P. aphidis can be used for biocontrol of diverse fungal and bacterial phytopathogens. Here demonstrate activity of two semi-purified fractions from P. aphidis, one containing the antimicrobial metabolites and the other containing the resistance inducing metabolites. Our results from the in vitro experiments with the antimicrobial extract show that P. aphidis metabolites strongly inhibit important fungal and bacterial phytopathogens. In planta experiments demonstrated a significant, dose-dependent reduction in disease infection when a spore suspension of B. cinerea was treated or exposed to the extracted metabolites. From the other hand, our results showed that the application a semi-purified aqueous fraction from P. aphidis on tomato plants rapidly up-regulated the expression of defense-related genes, which are associated with both the induced systemic resistance and the systemic acquired resistance pathways. In conclusion, this study further enhances our understanding of the biochemical mechanisms behind P. aphidis main modes of action: antibiosis and induced resistance. It also demonstrates the great potential of this unique biocontrol agent as a source for new natural-based pesticides and/or enhanced resistance substances.