Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 4, 2005
Publication Date: December 20, 2005
Citation: Keith, L.M., Sewake, K., Zee, F.T. 2005. Isolation and characterization of burkholderia gladioli from orchids in Hawaii. Plant Disease. 89:1273-1278. Interpretive Summary: Bacterial diseases are a constant problem for the orchid industry in Hawaii. Typical symptoms include leaf spots and soft rots. A variety of orchid genera, including Dendrobium, Oncidium, and Miltonia are affected. A survey was conducted to determine the main bacteria causing the problems. Bacteria from orchids exhibiting disease symptoms were isolated and identified using physiological characteristics and molecular techniques. Results indicate that Burkholderia gladioli is a commonly found pathogen on orchids in Hawaii with the potential to cause serious damage if not monitored and controlled.
Technical Abstract: Bacterial strains were isolated from orchids exhibiting disease symptoms in Hawaii. Small to large leaf spots with or without water-soaking and/or soft rots were observed on various orchid genera including Dendrobium, Oncidium, and Miltonia species and hybrids. Bacteria isolated and cultured from the lesions were tentatively identified using API strips and standard physiological and biochemical tests, and confirmed by species-specific PCR and sequencing of the 16S rRNA gene. The most common bacteria identified were Burkholderia gladioli. The variation in pathogenic, morphological, cultural and molecular characteristics of orchid isolates of B. gladioli was evaluated. Testing B. gladioli isolates using media containing copper or streptomycin indicated varying levels of resistance. Field and laboratory data suggest the frequent use of these chemicals in nurseries may have inadvertently resulted in developing copper and streptomycin resistance in B. gladioli from orchids.