ABSTRACT
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.
Subject(s)
Enterobacter/genetics , Eucalyptus/microbiology , Plant Diseases/microbiology , DNA, Bacterial/genetics , DNA, Ribosomal/genetics , Enterobacter/classification , Enterobacter/isolation & purification , Enterobacter/pathogenicity , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/genetics , Uruguay , VirulenceABSTRACT
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)).
Subject(s)
Condiments/microbiology , Food Microbiology , Glucose/metabolism , Leuconostoc/classification , Leuconostoc/isolation & purification , Bacterial Proteins/analysis , Bacterial Proteins/isolation & purification , DNA, Bacterial/chemistry , DNA, Bacterial/isolation & purification , DNA, Ribosomal/chemistry , DNA, Ribosomal/isolation & purification , Electrophoresis, Polyacrylamide Gel , Genes, Bacterial , Genes, rRNA , Leuconostoc/chemistry , Leuconostoc/metabolism , Molecular Sequence Data , Nucleic Acid Hybridization , Phylogeny , Proteome , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNAABSTRACT
Three heterofermentative lactic acid bacteria, obtained from Greek and Belgian artisanal wheat sourdoughs, were preliminarily identified as Lactobacillus brevis-like after screening using whole-cell protein fingerprinting and 16S rRNA gene sequence analysis. The three sourdough isolates showed nearly identical sequences (>99.7 % sequence similarity), and highest similarities of 98.2 and 97.6 % were obtained to the species Lactobacillus spicheri and Lactobacillus brevis, respectively. Growth characteristics, biochemical features, amplified fragment length polymorphism fingerprinting, DNA-DNA hybridizations and DNA G+C contents demonstrated that the isolates represent two novel Lactobacillus species. The names Lactobacillus acidifarinae sp. nov. and Lactobacillus zymae sp. nov. are proposed and the type strains are LMG 22200(T) (=R-19065(T)=CCM 7240(T)) and LMG 22198(T) (=R-18615(T)=CCM 7241(T)), respectively.
Subject(s)
Bread/microbiology , Lactobacillus/classification , Triticum/microbiology , Bacterial Proteins/chemistry , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/analysis , DNA, Ribosomal/analysis , Lactobacillus/genetics , Lactobacillus/growth & development , Lactobacillus/isolation & purification , Molecular Sequence Data , Nucleic Acid Hybridization , Polymorphism, Restriction Fragment Length , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Species SpecificityABSTRACT
Four isolates, which were obtained from Belgian, Moroccan and Romanian dairy products, constituted a homogeneous but unidentified taxon after screening with whole-cell protein fingerprinting. Complete 16S rRNA gene sequence analysis classified representative strains in the genus Enterococcus. Highest sequence similarities of 98.6 and 98.0 % were obtained with the species Enterococcus sulfureus and Enterococcus saccharolyticus, respectively. Growth characteristics, biochemical features, tRNA intergenic length polymorphism analysis, DNA-DNA hybridization and DNA G+C contents of selected strains demonstrated that they represent a single, novel Enterococcus species. It differs phenotypically from other enterococci in characteristics commonly considered as typical of this genus: no growth in 6.5 % NaCl or 0.4 % sodium azide, and no acid production from a wide range of carbohydrates. The name Enterococcus saccharominimus sp. nov. is proposed for this novel species; the type strain (LMG 21727(T)=CCM 7220(T)) was isolated from contaminated pasteurized cow's milk.
