Caracterização e identificação de isolados bacterianos patogênicos ao cafeeiro

Abstract

Diseases are among the factors which affect the productivity and yield of coffee (Coffea arabica L.), highlighting those caused by bacteria: Pseudomonas syringae pv. garcae, P. syringae pv. tabaci, P. cichorii, Burkholderia andropogonis and Xylella fastidiosa. Among the main challenges faced by plant pathologists is the correct diagnosis of these diseases, since the symptoms and biochemical tests have not been sufficient to distinguish these bacterial diseases at the species and pathovar levels. Molecular techniques such as polymerase chain reaction (PCR) have allowed the detection of pathogens quickly and with a high level of sensitivity when compared to traditional methods. Variations of PCR, such as BOX- PCR, have been effective in identifying plant pathogenic bacteria, differentiating isolates and evaluating the genetic diversity of pathogens. Thus, the objectives of this work were: characterize, identify, and differentiate coffee plant pathogenic bacterial isolates through biological, biochemical and molecular techniques. In order to do this, isolates were obtained from infected coffee plants, collected in various municipalities in Minas Gerais, Brazil. They were submitted to pathogenicity, biochemical and molecular assays. Of 160 isolates obtained, 80 were pathogenic to coffee and subjected to biochemical tests, BOX- PCR and PCR using specific primers. It was possible to identify P. cichorii and Pseudomonas syringae isolates, which produce tabtoxin. However, it was not possible to identify Pseudomonas syringae isolates at the pathovar level.