Genetic analyses of Pseudomonas syringae isolates from Belgian fruit orchards reveal genetic variability and isolate-host relationships within the pathovar syringae, and help identify both races of the pathovar morsprunorum

Abstract

A collection of Pseudomonas syringae and viridiflava isolates was established between 1993 and 2002 from diseased organs sampled from 36 pear, plum and cherry orchards in Belgium. Among the 356 isolates investigated in this study, phytotoxin, siderophore and classical microbiology tests, as well as the genetical methods REP-, ERIC-and BOX-(collectively, rep-) and IS50-PCR, enabled identification to be made of 280 isolates as P. syringae pv. syringae (Pss), 41 isolates as P. syringae pv. morsprunorum (Psm) race 1, 12 isolates as Psm race 2, three isolates as P. viridiflava and 20 isolates as unclassified P. syringae. The rep-PCR methods, particularly BOX-PCR, proved to be useful for identifying the Psm race 1 and Psm race 2 isolates. The latter race was frequent on sour cherry in Belgium. Combined genetic results confirmed homogeneities in the pvs avii, and morsprunorum race 1 and race 2 and high diversity in the pv. syringae. In the pv. syringae, homogeneous genetic groups consistently found on the same hosts (pear, cherry or plum) were observed. Pathogenicity on lilac was sometimes variable among Pss isolates from the same genetic group; also, some Psm race 2 and unclassified P. syringae isolates were pathogenic to lilac. In the BOX analyses, four patterns included 100% of the toxic lipodepsipeptide (TLP)-producing Pss isolates pathogenic to lilac. Many TLP-producing Pss isolates non-pathogenic to lilac and the TLP-non-producing Pss isolates were classified differently. Pseudomonas syringae isolates that differed from known fruit pathogens were observed in pear, sour cherry and plum orchards in Belgium.

Molecular characterization of Pseudomonas syringae pvs. from different host plants by repetitive sequence-based PCR and multiplex-PCR

“…PCR detection of cfl gene in pv. morsprunourm race 1 was reported by Gilbert et al (2009), Bultreys and Kaluzna (2010) and Kaluzna et al (2010). According to these authors, while most of the pv.…”

“…rep-PCR analysis was performed using two primer sets for REP (REP IR-I/REP 2-I) and ERIC (ERIC1R/ ERIC2) and two primers for BOX-PCR (BOX A1R and (GTG) 5 ), as recommended by Marques et al (2008) and Gilbert et al (2009 of template DNA. The amplification conditions for REP-PCR consisted of an initial denaturation at 95 for 4 min, followed by 30 cycles (denaturation at 94°C for 55 s, primer annealing at 42°C for 65 s and primer extension at 65°C for 7 min) and a final extension at 65°C for 12 min.…”

“…syringae strains, with the findings revealing high genetic heterogeneity between P. syringae pv. syringae strains originating from different and the same hosts (Natalini et al, 2006;Gilbert et al, 2009;Kaluzna et al, 2010;Ivanović et al, 2012). Repetitive element sequence-based PCR (rep-PCR) is based on three main sets of repetitive DNA elements: the repetitive extragenic palindromic (REP) elements (REP-PCR), the enterobacterial repetitive intergenic consensus (ERIC) sequences (ERIC-PCR) and BOX elements (BOX-PCR), and this method is successful in typing a variety of bacteria, as well as P. syringae (Vicente, Roberts, 2007;Marques et al, 2008;Kaluzna et al, 2010).…”

Genetic Diversity Among Pseudomonas syringae pv. morsprunorum Isolates from Prunus mume in Korea and Japan by Comparative Sequence Analysis of 16S rRNA Gene

“…Especially, BOX-PCR has been shown to be useful for identifying P. syringae pv. morsprunorum race 1 and race 2 (Gilbert et al, 2009).…”

“…morsprunorum LMG 2222 and LMG 5075, which were identified previously as P. syringae pv. morsprunorum race 1 and race 2, respectively, by BOX-PCR (Gilbert et al, 2009), were used as reference strains. Among the unclassified strains, 15 strains from Korea and Japan belonged to P. syringae pv.…”