Loop-mediated isothermal amplification (LAMP) for rapid detection of Rhodococcus fascians on ornamentals

Rhodococcus fascians (Rf) is of growing concern to ornamental growers due to its wide host range and the lack of effective control methods. Virulent strains of this gram-positive bacterium cause fasciation, leafy gall and shoot proliferation in susceptible host plants by interfering with the plant&#...

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Bibliographic Details
Published in:Phytopathology 2009-06, Vol.99 (6), p.S117-S117
Main Authors: Serdani, M, Curtis, M, Putnam, M L
Format: Article
Language:English
Subjects:
Agrobacterium tumefaciens
Rhodococcus fascians
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Summary:Rhodococcus fascians (Rf) is of growing concern to ornamental growers due to its wide host range and the lack of effective control methods. Virulent strains of this gram-positive bacterium cause fasciation, leafy gall and shoot proliferation in susceptible host plants by interfering with the plant's hormone balance. Current detection methods, including polymerase chain reaction (PCR), are expensive and not readily transferable to growers. We have developed a LAMP assay to rapidly detect virulent Rf strains on plant tissue without the need for expensive equipment. A set of four primers were designed to detect a conserved, 191 bp region of the FasR virulence gene of Rf. A total of 20 virulent Rf isolates from a range of different geographical areas and hosts was tested and detected with our LAMP assay. LAMP products were run on a gel and sequenced, aligning with the Rf virulence gene in GenBank. Our primers did not detect 6 avirulent Rf strains or other bacterial species that are known to occur on plant surfaces, including Agrobacterium tumefaciens, another problematic gall-forming pathogen found in nurseries. This assay is able to detect the equivalent of 5 x 10 super(3) cfu's of Rf per LAMP reaction, which is comparable to PCR sensitivity. We conclude that our LAMP assay is a sensitive, specific, rapid and cost-effective method to detect Rf on plants, with potential application in nurseries.
ISSN:0031-949X