Isolation and identification of <i>Burkholderia gladioli</i> on <i>Cymbidium</i> orchids in Korea

<p>Bacterial diseases of <i>Cymbidium</i> orchids continue to threaten the floriculture industry. Bacterial isolates were isolated and cultured from <i>Cymbidium</i> plants exhibiting disease symptoms: black lesions with or without water-soaking on leaves. To identify the bacterial isolates, we performed polymerase chain reaction (PCR) amplification using species-specific primers. The pathogen was tentatively identified as <i>Burkholderia gladioli</i>, which was first described as a phytopathogen, and later associated with human infections, especially with patients with cystic fibrosis. PCR-restriction fragment length polymorphism analysis of 16S ribosomal DNA (rDNA) products digested with <i>Hinf</i>I and sequencing of the 16S rDNA confirmed the isolate as <i>B. gladioli</i>. <i>Burkholderia gladioli</i> strains infecting plants are divided into two pathovars: <i>alliicola</i> and <i>gladioli</i>. Pathogenicity tests showed that the isolate proved to be pathogenic to <i>Cymbidium</i> orchid but not to onion plants, a common host for <i>B. gladioli</i> pv. <i>alliicola</i>. To the best of our knowledge, this is the first report of <i>B. gladioli</i> in <i>Cymbidium</i> orchids in Korea.</p>