|STANOSZ, G - UNIV OF WISCONSIN
|HEIMANN, M - UNIV OF WISCONSIN
|Lee, Ing Ming
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/1997
Publication Date: N/A
Interpretive Summary: Phytoplasmas, formerly called mycoplasmalike organisms, are associated with diseases in several hundred plant species. Thus far, none has been cultured in vitro. The development of molecular-based tools, especially polymerase chain reaction (PCR) assays using universal primers designed from conserved gene sequences, has made it possible for us to detect and identify a wide array of phytoplasmas associated with infected plants or insects. Numerous new phytoplasma strains have been reported in the last four years. Recently, we have found that the popular ornamental perennial plant purple coneflower, native to open woods and prairies of the eastern U.S., exhibited symptoms associated with diseases caused by phytoplasmas in Dane County, WI. In this study we have applied DAPI DNA staining combined with sensitive nested PCR assays and detected a phytoplasma strain. Based on DNA finger printing of PCR amplified 16S rRNA, we identified this associated phytoplsma is a strain of aster yellows phytopasma. The information and pathogen-identification technology will be of benefit to diagnosticians and to APHIS for implementation of new quarantine regulations.
Technical Abstract: DAPI staining indicated that all symptomatic purple coneflower may be associated with phytoplasmas. Nested PCR detected phytoplasmas from all symptomatic samples confirming the presence of phytoplasmas. Based on restriction fragment length polymorphism (RFLP) analysis of PCR amplified 16SrDNA sequences indicated that the associated phytoplasmas belonged to a subgroup (16rI-A) of aster yellows phytoplasma group (16SrI).