Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 9/25/2006
Publication Date: 11/27/2006
Citation: Francis, M., Civerolo, E.L., Doddapaneni, H., Lin, H., Bruening, G. 2006. New standard protocol for diagnosis of xylella fastidiosa [abstract]. CDFA Pierce's Disease Control Program Research Symposium. p.203.
Technical Abstract: The Interim Commission on Phytosanitary Measures of the International Plant Protection Convention (IPPC) adopted recommendations on the publication of International Standards for Phytosanitary Measures (ISPM). This guideline produces standardized documents describing procedures and methods for the detection and identification of pests. The documents are reviewed by a panel of experts which also includes members from the regional plant protection organizations (i.e. NAPPO, EPPO, COSAVE, etc). These protocols describe procedures and methods for detection and identification of pests that are regulated by contracting parties and relevant for international trade. These are addressed to diagnosticians/diagnostic laboratories performing official tests as part of phytosanitary measures and provide reliable diagnostic protocol(s) for relevant pests. There is a need to actualize the protocols for detection of Xylella fastidosas (Xf) in several hosts. Our group was designated to draft such a document for Xf detection in 2005. Here we propose to update that protocol in the light of recently developed Xf diagnostics procedures and genomic data for more specific and sensitive PCR detection. The proposed protocol also includes the recently developed bioassay for Xf in the model plant Nicotiana tabacum cv. SR-1. This highly sensitive host is an excellent indicator plant, to test the pathogenicity of Pierce’s disease and almond leaf scorch strains of Xf. The procedure includes use of in vitro-propagated tobacco plants grown in controlled climate chambers. The SR-1 plants are grown in small pots to reduce space requirements, and symptoms appear in only 6-8 weeks. Recognized Xf strains and Xf isolates from different plant hosts show distinct symptoms on SR-1 tobacco, adding to the usefulness of this experimental host. The protocol is applicable to surveys, quarantine and certification programs. The use of a standard procedure will permit comparison of experimental data from different regions (ring tests) and validate the results for detection of Xylella fastidiosa in different hosts. The application of a standardized detection procedure should be a useful tool in several activities of the Pierce’s Disease Control Program in California.