Genome Analysis of Erwinia amylovora Strains Responsible for a Fire Blight Outbreak in Korea

Abstract

Erwinia amylovora is a plant-pathogenic bacterium that causes the fire blight disease in Rosaceae plants. Since fire blight is highly contagious and results in serious losses once introduced, it is regulated as a quarantine disease. Recently, for the first time in East Asia, fire blight emerged in Korea with strains of E. amylovora being isolated from lesions of infected trees. Five of those strains were selected and subjected to whole-genome shotgun sequencing. Each strain had two circular replicons, a 3.8-Mb chromosome and a 28-kb plasmid. The genome sequences were compared with those of other E. amylovora strains isolated from different hosts or geographical regions. Genome synteny was analyzed and sequence variations including nucleotide substitutions, inversions, insertions, and deletions were detected. Analysis of the population genomic structure revealed that the five strains form a distinct structural group. Phylogenomic analysis was performed to infer the evolutionary relationships among E. amylovora strains, which indicated that the Korean isolates, all descended from a common ancestor, are closely related to a lineage of North American strains. These results provide useful information for understanding the genomic dynamics of E. amylovora strains including those in Korea, developing genetic markers for surveillance of the pathogen or diagnosis of the disease, and eventually developing measures to eradicate it.

Genome sequencing provides new insights on the distribution of Erwinia amylovora lineages in northern Italy

“…1A). Within the Widely Prevalent clade, North American isolates formed a subclade that included also five recent isolates from South Korea (Song et al, 2021) and that was well separated from a second subclade that is predominantly European but also includes isolates from New Zealand, Middle East and North Africa. The European subclade can be further subdivided into two major branches, both of which include isolates from Trentino.…”

Variability within a clonal population of Erwinia amylovora disclosed by phenotypic analysis

“…The etiological agent responsible for this disease is the Erwiniaceae Gram-negative Erwinia amylovora ( Vanneste, 2000 ; Adeolu et al, 2016 ), a plant pathogen recommended as quarantine pests by EPPO ( EPPO, 2020 ), characterized by a high aggressiveness paralleled by a lack of efficient phytosanitary treatments. Described in the late 1700s in North America, it was only in the second half of the XX th century that E. amylovora reached many other countries ( Llop et al, 2008 ; McGhee & Sundin, 2012 ; Pucci, L’Aurora & Loreti, 2013 ; Llorente et al, 2017 ; Song et al, 2020 ; Mendes et al, 2021a ). Intensive agriculture and the free-trade agreement among countries have facilitated the distribution of susceptible cultivars to fire blight, making commercial exchange an important factor in disease dissemination ( Ivanović et al, 2012 ).…”

In Vitro Evaluation of Five Antimicrobial Peptides against the Plant Pathogen Erwinia amylovora

“…The etiological agent responsible for this disease is the quarantine bacterium Erwinia amylovora (Burril) Winslow et al, a Gram-negative of the Erwiniaceae family, which has been considered as one of the top ten plant pathogenic bacteria [4,5]. This pathogen was first reported in North America, but is currently spread to Europe (United Kingdom, Spain, France, Italy, Hungary, and Portugal), South Korea, New Zealand, and the Middle East [6][7][8][9][10][11][12][13][14].…”