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Erwinia amylovora, the causative phytopathogen for fire blight, is a major threat to apple and pear. A nonpathogenic E. amylovora strain CP200242 was recently isolated from a pear orchard in South Korea. The nonpathogenicity of strain CP200242 was confirmed by inducing a hypersensitive reaction on tobacco leaves and by inoculating immature apple fruits and seedlings with bacterial suspensions. Herein, we report the complete genome sequencing of strain CP200242 data and provide some comparative genomic analysis against strain TS3128 and other closely related Erwinia species. Variant calling indicated that strain CP200242 had 29 variations in the annotated regions compared with strain TS3128, and six gene variants were related to pathogenesis. These genomic data provide valuable information on molecular differences between strains that may be useful for the control of the disease and enhance our understanding of the virulence factors in an E. amylovora reference genome. [Figure: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The present study describes a SYBR Green real-time quantitative (q) PCR assay to detect Erwinia pyrifoliae in plants. E. pyrifoliae, first described in South Korea, is a phytopathogenic bacterial species in the genus Erwinia. In particular, specific detection, quantitation, and identification of E. pyrifoliae is still challenging, as symptoms resulting from its colonization of Asian pear blossoms are very similar to those caused by E. amylovora. E. pyrifoliae has biochemical, phenotypic, and genetic properties similar to those of E. amylovora. Moreover, other Erwinia species, including E. tasmaniensis and E. billingiae, are also detected by currently available molecular methods and with traditional methods as well. Therefore, in this study, previously published genome sequences of the genera Erwinia and Pantoea were compared to exploit species-specific genes for use as improved qPCR targets to detect E. pyrifoliae. In silico analyses of the selected gene and designed primer sequences, in conjunction with bio-SYBR Green real-time qPCR, confirmed the robustness of this newly developed assay. Consequently, the bio-SYBR Green real-time qPCR-based protocols developed here can be used for rapid and specific detection of E. pyrifoliae. They will potentially simplify and facilitate diagnosis and monitoring of this pathogen and guide plant disease management. [Figure: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.