Bioprospecting of fluorescent bacteria of the genus Pseudomonas in the biocontrol of the foliar blight of signal grass (Urochloa brizantha)

Abstract

This study aims to determine if fluorescent bacteria from the genus Pseudomonas from non-disturbed potentially suppressive Amazonian soils have potential as biocontrol agents against Rhizoctonia solani anastomosis group AG-1 IA, the causal agent of the foliar blight and sudden death of pastures from genus Urochloa (formerly Brachiaria), in the Northern region of Brazil. This disease causes great losses in pasture yields in Brazil and is particularly difficult for management. Considering the inexistence of any economically viable, ecologically sustainable and even slightly efficient management strategies for this disease, biological control seems to be the only alternative to minimize the impact of the foliar blight and death of signal grass pastures. Specifically, we aim to: Perform molecular identification of selected fluorescent Pseudomonas isolates as potential biocontrol agents; ii. Carry out an in vitro screening of fluorescent Pseudomonas isolates for their potential as biocontrol agents of R. solani AG-1 IA; and iii. Determine if the in vitro selected bacterial strains maintain the in vivo biocontrol ability of the foliar blight disease on signal grass. Because these bacteria were obtained from non-disturbed potentially suppressive soils in areas close to where foliar blight disease occurs, our hypothesis is that potential biocontrol agents selected in our study will be able to control the disease when reintroduced in the pasture agroecosystems from Northern Brazil. (AU)