Diagnosis of bacterial sheath brown rot of rice (Pseudomonas fuscovaginae)

Three identification tests were assessed for rapid and accurate diagnosis of bacterial sheath brown rot of rice caused by Pseudomonas fuscovaginae: - a biochemical profile comprised of eight characteristics: levan and 2 ketogluconate production, presence of cytochrome C oxidase and of arginine dihydrolase, production of acids from inositol, sucrose, sorbitol and trehalose; - antigenicity, by tube agglutination, with an antiserum to a strain of P. fuscovaginae from Madagascar. - pathogenicity on rice seedlings. They were applied to seven known strains of P. fuscovaginae and to 136 fluorescent bacterial strains isolated from rice plants originating from Brazil, Cameroon, Madagascar, Réunion and Rwanda. Application of at least two out of three tests was required in order to distinguish P. fuscovaginae from other fluorescent pseúdomonads. The presence of the pathogen was confirmed in Madagascar and Rwanda. (Texte intégral