Molecular mechanisms of bioantagonistic Pseudomonas for the phytosanitary control of vegetables

PASTOR, NICOLÁS; ROSAS, SUSANA; ROVERA, MARISA

Villa General Belgrano, Córdoba

Workshop; I Workshop sobre Pseudomonas y Burkholderia; 2007

In 1987 the National Academy of Sciences of the United States defined the biological control as ?the use of natural or modified organisms, genes or its products, in order to reduce the effects of undesirable organisms favoring desirable organisms, such as crops, trees, animals, insects and beneficial microorganisms?.The advance in the biocontrolstudies not only allows the use of bacterial strains (that havethe capacity of controlling the progress of the pathogen) in the field, but rather tends to use secondary products of the microbial metabolism as biocontrol agents.It is planned the study of Pseudomonas spp. strains, as potential bioantagonists of fungal pathogens of vegetables, evaluating the possible molecular mechanisms of direct antagonism (production of compounds with antimicrobial action, such as enzymes and antibiotics) which wouldallow the control of diseases preserving the phytosanityof the products, without ecotoxic effects. During the first year of the scholarship, it is projected the isolation of soil borne Pseudomonas from rhizosphere soil, as well as carrying out assays of antagonism in dual culture in Petri dishes and assays in vegetables [Pepper (Capsicum annuum) and Tomato (Licopersicon esculentum Mill.)], under controlled conditions. The pathogenicityof fungicstrains (Sclerotium rolfsii, Fusarium solani, Fusarium verticillioides., Alternaria alternata), the effect of the selected antagonistic agent/s upon the cultivations and the biocontrol activity will be evaluated. Assays of enzymatic activity (chitinolytic activity, β-1, 3-Glucanase, caseinolityc activity) will allow elucidating some of the possible mechanisms involved in the antibiosis processes.