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URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/9887

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Bacterial halo blight of coffee crop: aggressiveness and genetic diversity of strains
(Instituto Agronômico (IAC), 2018-01) Maciel, Karen Wolf; Destefano, Suzete Aparecida Lanza; Beriam, Luis Otavio Saggion; Almeida, Irene Maria Gatti de; Patricio, Flavia Rodrigues Alves; Rodrigues, Lucas Mateus Rivero; Guerreiro Filho, Oliveiro
Bacterial halo blight, caused by Pseudomonas syringae pv. garcae, is an important disease of coffee crop occurring in Brazil and other countries. In recent years, outbreaks of this disease have damaged several coffee crops in Brazil. Aggressiveness and genetic diversity of 25 strains of P. s. pv. garcae, obtained between the years 1958 and 2011, in 23 cities of São Paulo and Minas Gerais states, as well as three strains from Kenya were evaluated in this study. The strains were inoculated on coffee seedlings cultivar Mundo Novo, and their genetic diversity was evaluated by ERIC-PCR, REP-PCR, and their combination. All the strains were pathogenic to the coffee seedlings; the results of pathogenicity tests, in both experiments, could be divided in four aggressiviness classes (highly aggressive; aggressive; moderately aggressive and less aggressive). The Kenyan strains grouped separately from the Brazilian strains with ERIC-PCR and the combination of ERIC- and REP-PCR. The Brazilian strains could be grouped in two sub-clusters, the first including the older strains, obtained from 1958 to 1978, and the other comprising the remaining strains. With a few exceptions, strains isolated from 1997 to 2011, grouped mainly by their region of origin, were predominantly isolated from higher altitude regions, above 800 m. This probably occurred because the climatic conditions that prevail in these regions, characterized by milder temperatures and regular rainfall, are favorable for the coffee crop and for the production of high quality coffee beverage, but can be also favorable to bacterial halo blight.
First report of mixed infection by Pseudomonas syringae pathovars garcae and tabaci on coffee plantations
(Instituto Agronômico (IAC), 2017-10) Rodrigues, Lucas Mateus Rivero; Sera, Gustavo Hiroshi; Guerreiro Filho, Oliveiro; Beriam, Luis Otavio Saggion; Almeida, Irene Maria Gatti de
The bacterial-halo-blight (Pseudomonas syringae pv. garcae) is disseminated by the main coffee areas in the producing states of Brazil. On the other hand, the disease bacterial-leaf-spot (Pseudomonas syringae pv. tabaci) was reported only once in coffee seedlings in a sample collected in the State of São Paulo. In mid-2015, samples of coffee leaves with symptoms of foliar lesions surrounded by yellow halo, were collected in coffee plantations in the State of Paraná and fluorescent bacteria producing or not brown pigment in culture medium were isolated and determined as belonging to the Group I of P. syringae. Through biochemical, serological and pathogenicity tests, the pathogens were identified as P. syringae pv. garcae and P. syringae pv. tabaci, with prevalence of isolates belonging to pathovar tabaci and, as well as in certain samples, it was identified simultaneous infection by both etiological agents. Then, this is the first report of associated occurrence of garcae and tabaci pathovars of P. syringae and of the incidence of “bacterial-leaf-spot” under field conditions and in the State of Paraná.