RESUMEN
AIMS: This study was performed to identify bacterial strains isolated simultaneously with Pantoea species from Eucalyptus trees showing symptoms of bacterial blight and dieback in Uruguay. METHODS AND RESULTS: Several molecular techniques including 16S rRNA and rpoB gene sequencing and DNA-DNA hybridization were used to characterize the gram-negative, facultatively anaerobic, slime-producing bacterial strains isolated along with Pantoea species from Eucalyptus. Hypersensitivity reactions (HR) and pathogenicity tests were performed on tobacco and Eucalyptus seedlings, respectively. The isolates clustered closely with the type strain of Enterobacter cowanii in both phylogenetic trees constructed. The DNA-DNA similarity between the isolates and the type strain of Ent. cowanii ranged from 88% to 92%. A positive HR was observed on the tobacco seedlings, but no disease symptoms were visible on the inoculated Eucalyptus seedlings. CONCLUSIONS: Enterobacter cowanii was isolated from trees with symptoms of bacterial blight although strains of this bacterial species do not appear to be the causal agent of the disease. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides the first report of Ent. cowanii isolated from Eucalyptus. Its presence in Eucalyptus tissue suggests that it is an endophyte in trees showing symptoms of blight.
Asunto(s)
Enterobacter/genética , Eucalyptus/microbiología , Enfermedades de las Plantas/microbiología , ADN Bacteriano/genética , ADN Ribosómico/genética , Enterobacter/clasificación , Enterobacter/aislamiento & purificación , Enterobacter/patogenicidad , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Uruguay , VirulenciaRESUMEN
Three lactic acid bacterial (LAB) strains obtained from a Malaysian acid-fermented condiment, tempoyak (made from pulp of the durian fruit), showed analogous but distinct patterns after screening by SDS-PAGE of whole-cell proteins and comparison with profiles of all recognized LAB species. 16S rRNA gene sequencing of one representative strain showed that the taxon belongs phylogenetically to the genus Leuconostoc, with its nearest neighbour being Leuconostoc fructosum (98 % sequence similarity). Biochemical characteristics and DNA-DNA hybridization experiments demonstrated that the strains differ from Leuconostoc fructosum and represent a single, novel Leuconostoc species for which the name Leuconostoc durionis sp. nov. is proposed. The type strain is LMG 22556(T) (= LAB 1679(T) = D-24(T) = CCUG 49949(T)).