Genetic Diversity ofPseudomonas syringaepv.actinidiaeStrains from Different Geographic Regions in China

Abstract

Pseudomonas syringae pv. actinidiae (Psa) causes kiwifruit bacterial canker (KBC), with a severe infection of the kiwifruit plant resulting in heavy economic losses. Little is known regarding the biodiversity and genetic variation of populations of Psa in China. A collection of 269 strains of Psa were identified from 300 isolates obtained from eight sampling sites in five provinces in China. The profiles of 50 strains of Psa and one strain of P. syringae pv. actinidifoliorum (Psaf) were characterized by Rep-, IS50-P, and RAPD-PCR. Discriminant analysis of principal coordinates (DAPC), principal component analysis (PCA), and hierarchical cluster analysis were used to analyze the combined fingerprints of the different PCR assays. The results revealed that all isolates belonged to the Psa3 group, that strains of Psa from China have broad genetic variability that was related to source geographic region, and that Chinese strains can be readily differentiated from strains from France, but are very similar to those from Italy. Multilocus sequence typing (MLST) of 24 representative isolates using the concatenated sequences of five housekeeping genes (cts, gapA, gyrB, pfk, and rpoD) demonstrated that strain Jzhy2 from China formed an independent clade compared to the other biovars, which possessed the hopH1 effector gene, but lacked the hopA1 effector gene. A constellation analysis based on the presence or absence of the four loci coding for phytotoxins and a cluster analysis based on the eleven effector genes showed that strains from China formed two distinct clades. All of the strains, including K3 isolated in 1997 from Jeju, Korea, lacked the cfl gene coding for coronatine. In contrast, the tox-argK gene cluster coding for phaseolotoxin was detected in K3 and in the Biovar1 strains (K3, Kw30, and Psa92), and produced a false positive amplicon for the hopAM1-like gene in this study. To date, only one biovar (Biovar3) is represented by the strains of Psa from China, despite China being the center of origin for the kiwifruit.

Efficiency of Phage φ6 for Biocontrol of Pseudomonas syringae pv. syringae: An in Vitro Preliminary Study

“…According to our results, this phage can be used also against other Pseudomonas syringae pathovars, such as P. syringae pv. syringae , which are important phytopathogens for the agriculture sector because they can easily infect several horticultural plants [4,52,53,54,55,56], causing severe economic losses worldwide.…”

Pseudomonas syringae pv. actinidiae: Ecology, Infection Dynamics and Disease Epidemiology

“…Further studies identified natural openings and lesions as important entry sites for Psa, as well as the importance of lenticels and fresh cut in the infection process, as observed through a scanning electron microscope [13,14]. Furthermore, it was observed, through bacterial injections into leaf veins as described by Serizawa and Ichikawa [15], that bacteria can migrate from young leaves to twigs facilitating a systemic infection throughout the vine [8,12,13,[16][17][18]. The bacterium was retrieved in xylem vessels and phloem tissues, indicating that the systemic spread can rapidly reach potentially any tissue of the infected plant [14].…”

Genetic diversity ofPseudomonas syringaepv.actinidiae, pathogen of kiwifruit bacterial canker

“…Thus, after integrating this information and the numerous research results obtained so far, phylogeographical analyses were conducted; as a result, concrete scenarios of the origin and evolution of Psa are becoming apparent, as described below (e.g. Ushiyama, 1993;Sawada et al, 1997Sawada et al, , 1999Sawada et al, , 2002Sawada et al, , 2014bGenka et al, 2006;Mazzaglia et al, 2012;Butler et al, 2013;McCann et al, 2013McCann et al, , 2017Vinatzer et al, 2014;Bartoli et al, 2015;Ciarroni et al, 2015;Cunty et al, 2015b;Fujikawa & Sawada, 2016Baltrus et al, 2017;Vanneste, 2017;He et al, 2019).…”