Erwinia toletana sp. nov., associated with Pseudomonas savastanoi-induced tree knots

Abstract

Gram-negative bacteria were isolated from knots induced by Pseudomonas savastanoi in olive trees (Olea europaea L.). A total of nine endophytic bacterial strains were isolated, each from inside a different tree knot. Biochemical characterization indicated that all the strains belong to the family Enterobacteriaceae. Phylogenetic analyses of the 16S rRNA genes of these novel isolates revealed that they formed a homogeneous cluster within Erwinia species. DNA signatures of these isolates were identical to those described for the genus Erwinia. The strains formed a homogeneous group as shown by DNA-DNA hybridization analysis and numerical analysis of phenotypic data, clearly differentiated from all species of Erwinia with validly published names. The data provide strong evidence of the differentiation of these strains from the most closely related species. Therefore, these isolates represent a novel species, for which the name Erwinia toletana sp. nov. is proposed. The isolates are available at CFBP, CECT and ATCC. The G+C content is 52±0?5 mol%. The type strain is CFBP 6631 T (=A37 T =ATCC 700880 T =CECT 5263 T ). Ewing & Fife (1971, 1972 concluded that strains isolated from clinical sources and strains belonging to the Herbicola group of Dye (1969) are the same species and referred to them as the 'Enterobacter agglomerans-Erwinia herbicola' complex. Lelliott & Dickey (1984) defined Erwinia as associated with plants as pathogens, saprophytes or constituents of the epiphytic flora. They considered Erwinia herbicola as yellow and non-pigmented Erwinia-like organisms that exist either on plant surfaces or as secondary organisms in lesions caused by many plant pathogens, as described by Billing & Baker (1963). Gavini et al. (1989) described the new genus Pantoea and the species Pantoea agglomerans, which includes the type strains of Enterobacter agglomerans, Erwinia herbicola and Erwinia milletiae. Later, Erwinia ananatis (synonym Erwinia uredovora) and Erwinia stewartii were transferred to the genus Pantoea (Mergaert et al., 1993). Based on 16S rRNA gene phylogenetic analyses, plant-associated bacteria were reclassified into four genera: Erwinia, Pectobacterium, Brenneria and Pantoea (Hauben et al., 1998). Mergaert et al. (1999) reclassified nonpigmented Erwinia herbicola epiphytic strains isolated from trees as Erwinia billingiae, which clades within the first cluster of Hauben et al. (1998).Samples from diseased olive trees were collected from the Navahermosa and Chozas areas in the Toledo region of central Spain. Strains from knots were isolated according to the method of García de los Ríos (1999) and were grown on King's medium B (KB) and nutrient agar for 48 h at 25 uC. Two colony types were easily distinguishable on both agar media. Pure cultures were established by single colony isolation onto fresh KB agar. The first type was identified as Pseudomonas savastanoi. The second type, which corresponded to large (3-5 mm), mucilaginous, pigmented and non-pigmented colonies, was identified as a member of 3Present a...

Erwinia typographi sp. nov., isolated from bark beetle (Ips typographus) gut

“…The sequences of the type strains of Erwinia billingiae and Erwinia toletana were too short for the alignment (1218 and 1165 nt long, respectively) with the novel strains; therefore the sequences of E. toletana CFBP 6644 (GenBank accession no. AF130964) and E. billingiae Eb661 (FP236843) were used for the alignment (Rojas et al, 2004;Kube et al, 2010). Bayesian phylogenetic trees derived from these analyses are shown in Fig.…”

Bacterial multispecies studies and microbiome analysis of a plant disease

“…savastanoi (Marchi et al, 2009;Matas et al, 2009;Pérez-Martínez et al, 2008Ramos et al, 2012;Rodríguez-Moreno et al, 2009;Scortichini et al, 2004;Surico et al, 1985). The description of several virulence factors Iacobellis et al, 1994;Matas et al, 2009;Matas et al, 2012;Pérez-Martínez et al, 2010;Ramos et al, 2012;Rodríguez-Moreno et al, 2008Rodríguez-Palenzuela et al, 2010;Rojas et al, 2004;Surico et al, 1985) and the normal localization on the intercellular space of the parenchymal tissue as a biofilm structure are, to our knowledge, the main recent discoveries (Rodríguez-Moreno et al, 2009).…”

“…Several bacterial species have been isolated from olive knots using standard culturing methods, possibly indicating the presence of a multispecies bacterial community within the olive knot Ouzari et al, 2008;Rojas et al, 2004); many of these isolates belong to the genera Erwinia and Pantoea. It was of interest here to perform an exhaustive high-throughput analysis of the bacterial population inside olive knots since to our knowledge it has never been performed.…”

“…Interestingly, several other bacterial species have been isolated within the olive knot that are harmless or nonpathogenic to the olive plant Ouzari et al, 2008;Rojas et al, 2004). The possible role of these Pseudomonas savastanoi pv.…”

Epidemiology and Control of Plant Diseases Caused by Phytopathogenic Bacteria: The Case of Olive Knot Disease Caused by Pseudomonas savastanoi pv. savastanoi

“…The etiologic agent of olive knot disease has only been isolated from 5 to 10% of olive knots, similarly to that observed in other Psv hosts species, such as oleander and ash (García de los Ríos, 1989). Four new bacterial species belonging to the genus Pantoea were proposed in a study of endophytic bacteria from olive knots associated to Psv (Rojas, 1999) and one of them known as Erwinia toletana has been accepted as new species (Rojas et al, 2004). These bacteria would be incorporated to the knot subsequently to the infection caused by the etiologic agent, according to García de los Ríos (1989).…”