Spread of levan-positive populations of Pseudomonas savastanoi pv. savastanoi, the causal agent of olive knot, in central Italy

Marchi, Guido; Viti, Carlo; Giovannetti, Luciana; Surico, Giuseppe

doi:10.1007/s10658-005-0804-0

Cited by 26 publications

(24 citation statements)

References 26 publications

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“…The results support the classification of atypical levan‐positive strains isolated from olive plants as P. savastanoi (Iacobellis et al ., 1993; Marchi et al ., 2005). However, it remains to be established whether the grouping of all those strains into a single cluster is due to their geographical origin (central Italy) or to their phenotypic features.…”

Section: Discussionmentioning

confidence: 99%

“…savastanoi strains isolated from olive (34 strains), oleander (20 strains), ash (12 strains), privet (two strains) and jasmine (three strains), were used in this study (Table 1). Ten out of the 34 strains from olive were atypical levan‐positive strains isolated in central Italy (Iacobellis et al ., 1993; Marchi et al ., 2005). Pseudomonas amygdali NCPPB2610, P. syringae pv.…”

Section: Methodsmentioning

confidence: 99%

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Genetic characterization by fluorescent AFLP of Pseudomonas savastanoi pv. savastanoi strains isolated from different host species

et al. 2007

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The genetic diversity of 71 Pseudomonas savastanoi pv. savastanoi strains isolated from different host species and from diverse geographical regions was determined by fluorescent amplified fragment length polymorphism (f-AFLP) analysis. The study was carried out using three different selective primer combinations. Strains of P. syringae pv. syringae , P. syringae pv. phaseolicola , P. syringae pv. glycinea , P. syringae pv. tagetis and P. amygdali were also included as outgroups. Based on cluster analysis of f-AFLP data, all P. savastanoi pv. savastanoi strains showed a high degree of similarity, grouping in a cluster and forming a taxon clearly separate from outgroup strains. AFLP analyses failed to support placing strains of P. savastanoi pv. savastanoi , P. syringae pv. phaseolicola and P. syringae pv. glycinea in the same species. Strains of P. savastanoi pv. savastanoi formed subclusters that correlated with the host species. Strains identified within these subclusters were related to the geographical region where the strains were isolated. Strains of P. savastanoi pv. savastanoi from olive were divided into two subclusters. Strains from oleander were differentiated from those from ash and were divided into two additional subclusters, distinct from olive strains. Three strains isolated from jasmine showed a high level of similarity among them but, at a lower Dice similarity coefficient, were linked to a subcluster including olive strains. Finally, two strains isolated from privet were similar to strains from olive and were included in the same subcluster.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Genetic characterization by fluorescent AFLP of Pseudomonas savastanoi pv. savastanoi strains isolated from different host species

et al. 2007

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“…There is an important variation in virulence, with strains showing either low, intermediate or, most commonly, high virulence to diverse olive cultivars (Penyalver et al, 2006), and also variation in the size and morphology of tumours in artificial inoculations (Pérez-Martínez et al, 2007). Certain isolates in central Italy are nonfluorescent and produce levan, in contrast with the majority of other isolates (Marchi et al, 2005). Amplified fragment length polymorphism (AFLP) data cluster these levan-positive isolates separately from most of the common levan-negative isolates.…”

Section: Taxonomy and Population Biologymentioning

confidence: 99%

Pseudomonas savastanoi pv. savastanoi: some like it knot

Ramos

Matas

Bardaji

et al. 2012

Molecular Plant Pathology

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Summary Pseudomonas savastanoi pv. savastanoi is the causal agent of olive (Olea europaea) knot disease and an unorthodox member of the P. syringae complex, causing aerial tumours instead of the foliar necroses and cankers characteristic of most members of this complex. Olive knot is present wherever olive is grown; although losses are difficult to assess, it is assumed that olive knot is one of the most important diseases of the olive crop. The last century witnessed a large number of scientific articles describing the biology, epidemiology and control of this pathogen. However, most P. savastanoi pv. savastanoi strains are highly recalcitrant to genetic manipulation, which has effectively prevented the pathogen from benefitting from the scientific progress in molecular biology that has elevated the foliar pathogens of the P. syringae complex to supermodels. A number of studies in recent years have made significant advances in the biology, ecology and genetics of P. savastanoi pv. savastanoi, paving the way for the molecular dissection of its interaction with other nonpathogenic bacteria and their woody hosts. The selection of a genetically pliable model strain was soon followed by the development of rapid methods for virulence assessment with micropropagated olive plants and the analysis of cellular interactions with the plant host. The generation of a draft genome of strain NCPPB 3335 and the closed sequence of its three native plasmids has allowed for functional and comparative genomic analyses for the identification of its pathogenicity gene complement. This includes 34 putative type III effector genes and genomic regions, shared with other pathogens of woody hosts, which encode metabolic pathways associated with the degradation of lignin‐derived compounds. Now, the time is right to explore the molecular basis of the P. savastanoi pv. savastanoi–olive interaction and to obtain insights into why some pathovars like it necrotic and why some like it knot. Synonyms Pseudomonas syringae pv. savastanoi. Taxonomy Kingdom Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Family Pseudomonadaceae; Genus Pseudomonas; included in genomospecies 2 together with at least P. amygdali, P. ficuserectae, P. meliae and 16 other pathovars from the P. syringae complex (aesculi, ciccaronei, dendropanacis, eriobotryae, glycinea, hibisci, mellea, mori, myricae, phaseolicola, photiniae, sesami, tabaci, ulmi and certain strains of lachrymans and morsprunorum); when a formal proposal is made for the unification of these bacteria, the species name P. amygdali would take priority over P. savastanoi. Microbiological properties Gram‐negative rods, 0.4–0.8 × 1.0–3.0 μm, aerobic. Motile by one to four polar flagella, rather slow growing, optimal temperatures for growth of 25–30 °C; oxidase negative, arginine dihydrolase negative; elicits the hypersensitive response on tobacco; most isolates are fluorescent and levan negative, although some isolates are nonfluorescent and levan positive. Host range P. savastanoi pv. savastanoi cause...

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“…During a survey of olive groves in central Italy (Tuscany, Liguria and Umbria) in 2002 and 2003 to monitor the spread of an atypical levan‐positive population of Ps. savastanoi (Marchi et al ., 2005), a yellow‐pigmented bacterium was often observed on nutrient sucrose agar (NSA) (Varvaro & Surico, 1978) following isolation from both leaf and knot samples. This bacterium sometimes occurred at concentrations that made it difficult to isolate Ps.…”

Section: Introductionmentioning

confidence: 99%

Interaction between Pseudomonas savastanoi pv. savastanoi and Pantoea agglomerans in olive knots

et al. 2006

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Results of a survey of olive knot disease in central Italy in 2002 and 2003 showed that Pantoea agglomerans was found associated with the pathogen Pseudomonas savastanoi pv. savastanoi ( Ps. savastanoi ) in 70% of the olive knots examined. Pathogenicity tests in which these two bacteria were co-inoculated on the stems of 1-year-old olive plants at ratios of 1:1, 1:100 and 100:1 showed that the growth of P. agglomerans was apparently aided by the presence of an actively growing population of Ps. savastanoi . At the same time, however, a dominant population of P. agglomerans at the inoculation site tended to depress the growth of Ps. savastanoi , probably because of competition for space and nutrients between these bacteria and by means of antibiotic production by P. agglomerans. In some cases the association of P. agglomerans , which in culture was found to produce indole-3-acetic acid but not cytokinins, with Ps. savastanoi resulted in an increase in the size of knots. This boosting effect of P. agglomerans on proliferation was probably due to the release of IAA by this bacterium at the inoculation sites.

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Spread of levan-positive populations of Pseudomonas savastanoi pv. savastanoi, the causal agent of olive knot, in central Italy

Cited by 26 publications

References 26 publications

Genetic characterization by fluorescent AFLP of Pseudomonas savastanoi pv. savastanoi strains isolated from different host species

Genetic characterization by fluorescent AFLP of Pseudomonas savastanoi pv. savastanoi strains isolated from different host species

Pseudomonas savastanoi pv. savastanoi: some like it knot

Interaction between Pseudomonas savastanoi pv. savastanoi and Pantoea agglomerans in olive knots

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