Pseudomonas savastanoi pv. savastanoi: some like it knot

Abstract

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...

The Mangotoxin Biosynthetic Operon ( mbo ) Is Specifically Distributed within Pseudomonas syringae Genomospecies 1 and Was Acquired Only Once during Evolution

“…This bacterial species establishes an epiphytic population in association with a plant host's surfaces prior to infection. There are at least 50 pathovars, many of which cause a wide range of plant diseases that exhibit diverse symptoms, such as leaf or fruit lesions, cankers, blasts, and galls (1)(2)(3)(4)(5)(6)(7).…”

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).…”

“…The productivity of olive trees infected with Pseudomonas savastanoi pv. savastanoi is reduced and no effective treatment is yet in place Quesada et al, 2010;Ramos et al, 2012;Schroth et al, 1973;Young, 2004). The few studies of Pseudomonas savastanoi pv.…”

Knots Untie: Molecular Determinants Involved in Knot Formation Induced by Pseudomonas savastanoi in Woody Hosts

“…The ptz gene ( P seudomonas t rans- z eatin producing gene, also called ipt ; 705 nt), coding for an isopentenyl transferase (234 aa), is widely present in tumorigenic strains of P. savastanoi (Ramos et al, 2012). Thus, isolates of Psf inducing cankers, but not knots, on ash do not possess the ptz gene (Iacobellis et al, 1998).…”