Screening and mapping of fungal quorum sensing by ambient mass spectrometry: chemical profiling and localization of molecules involved in networking biocontrol among fungal agents and different phytopathogens

Abstract

The exchange of signaling molecules among microorganisms is commonly called quorum sensing (QS) and allows coordination of the microbial behaviors. These interactions among microorganisms, especially bacteria, have been studied since 60s. However, fungal intra-species metabolic exchange is still a new field of research. In this project, we propose the developing of a mass spectrometric method for the study of the exchange of signaling metabolites between the most used biocontrol fungal agent, Trichoderma harzianum, and phytopathogens species that attack several plants causing economic loss worldwide. Mass spectrometry, such as nano-desorption electrospray ionization mass spectrometry (Nano-DESI) and matrix assisted laser desorption ionization (MALDI) , has been recently employed to detect molecules secreted by both gram-positive and gram-negative bacteria and to study interactions between different species.Hereby, we propose the use of desorption electrospray ionization mass spectrometry (DESI-MS) profiling and imaging to monitor, characterize, and localize the metabolites released during the interaction between the most-marketed biocontrol agent, the fungus Trichoderma harzanium and the following phytophatogens: Moniliophthora roreri, (a fungus that attacks cacao fruits which is forbidden to import in Brazil since it did not infect yet the Brazilian plantations), Rhizoctonia solani (a fungus that attacks roots of cereals), Pythium ultimum (a fungus that attacks corn fields wordwide), Gaeumannomyces graminis var. tritici (the fungus that causes the most widespread cereal root disease in the world) and Phytophtora palmivora (a phytophatogen that attacks coconut, papaya and cacao plants) directly from the agar plate. The five phytophatogens mentioned above have been chosen due to their high dissemination worldwide and the economic loss caused. We expect to provide a significant advancement in the understanding the spatial-temporal dynamics of metabolite production during the interaction between the most marketed biocontrol agent and some world-spread phytopathogens. (AU)