Characterization of Chilean Pseudomonas syringae pv actinidiae strains isolated from infected orchards

Facultad de Ciencias/ Escuela de Biotecnología, Universidad Santo Tomás, Santiago, Chile
Facultad de Ciencias/Área de Genética, Universidad de Málaga, Málaga, Spain
Genética Molecular y Microbiología/Facultad de Ciencias Biológicas/Laboratorio de Biologia Vegetal, Pontificia Universidad Católica de Chile, Santiago, Chile
Subject Areas
Microbiology, Plant Science
Pseudomonas syringae pv. actinidiae, kiwifruit, PSA chilean strains, swimming and swarming motility
© 2017 Parada et al.
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Cite this article
Parada JP, Orellana M, Amaza L, Pérez-Martínez I, Holuigue L, Salinas P. 2017. Characterization of Chilean Pseudomonas syringae pv actinidiae strains isolated from infected orchards. PeerJ Preprints 5:e2787v1


Pseudomonas syringae pv. actinidiae (PSA) strain is a major problem for the kiwifruit industry worldwide. So far, 5 biovars of PSA have been identified, of which the most virulent form is biovar 3. This is the only biovar that has been detected in Chile, which is the third kiwifruit exporter country and is currently suffering from canker disease produced by PSA. Single nucleotide polymorphisms (SNPs) analyses have classified the biovar 3 strain into three groups: the European, the New Zealander and the Chilean groups, which have evolved from a common Chinese PSA ancestor. Although Chilean strains have been used in phylogenetic analysis, there is no information about genomic diversity within this group or whether they present microbiological characteristics that could affect its virulence. In this work we studied 15 Chilean bacterial isolates collected from orchards with canker disease symptoms, and classified them as PSA using a different PCR techniques. To gain more information on the relationship between the isolates we sequenced part of three conserved genes widely used to classify bacterial strains: gtl (Citrate Synthase), rpoD (Sigma subunit of RNA polymerase II) and gyrB (Gyrase B). Using these sequences we performed a phylogenetic analysis that included some PSA reference sequences. Fourteen PSA Chilean isolates were grouped with PSA reference strains and three of them formed a subgroup within the PSA clade, suggesting clear differences at the genomic level among the isolates. We evaluated three microbiological traits in all the isolates: motility (swimming and swarming), and ability to induce a hypersensitive response in tobacco plants. All the isolates were able to induce the hypersensitive response in tobacco plants and were also able to perform both types of movements in appropriated growing conditions.

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

Collection dates and places of PSA Chilean isolates

n.d= No data available

DOI: 10.7287/peerj.preprints.2787v1/supp-1


Concatenated sequences used to build the phylogenetic tree. The concatenate partial sequences of ctl, rpoD, gyrB genes of each PSA Chilean isolate and the reference strains used to build the phylogenetic tree, are showed in fasta format. The name of each strains is indicated at the beginning of each sequence.

DOI: 10.7287/peerj.preprints.2787v1/supp-2