|Kistler, H - Corby|
Submitted to: Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/24/2000
Publication Date: N/A
Citation: Interpretive Summary: In 1995 a new disease of the ornamental Canary Island Date Palm tree was first reported in Florida. The new disease, known as Fusarium wilt, has caused the loss of many of these prized and picturesque trees in both urban landscapes and in tree nurseries where they are grown for planting, both in the state and elsewhere. The disease is caused by a fungus known as Fusarium oxysporum f.sp. canariensis. Previous methods for confirming the presence of the fungus were laborious, lengthy, expensive and ultimately error-prone. This study validates a method previously developed by the authors for detecting the fungus so that it may be reliably identified in vanishing amounts and in less than a week. This DNA-based technique is a large improvement over previous detection methods that could take months to complete. This detection method for Fusarium wilt of Canary Island Date Palm is currently being used by the University of Florida Disease Diagnostic Laboratory and directly benefits those who use this service, including ornamental nurserymen and homeowners in the state of Florida. Infected trees can now be quickly detected and destroyed before they can endanger nearby healthy trees. This speedy method for detecting the fungus therefore will help to control the spread of the disease.
Technical Abstract: Fusarium oxysporum f.sp. canariensis causes vascular wilt disease of Phoenix canariensis, the Canary Island date palm. Seventy-two isolates of this fungus were obtained from diverse geographic locations including France, Japan, Italy, the Canary Islands, California, Florida, and Nevada. The isolates were tested for vegetative compatibility, and for similarities sbased on mitochondrial DNA (mtDNA), single-copy sequences, and repetitive DNA (pEY10) polymorphisms. Seventy percent of the isolates belonged to a single vegetative compatibility group (VCG 0240) and four closely related mitochondrial RFLP patterns were found. A subset of the isolates was further tested for single-copy RFLPs and repetitive DNA fingerprints. Only four single-copy RFLP haplotypes were found among 25 representative isolates of F. oxysporum f. sp. canariensis tested, using nine polymorphic single-locus probe/enzyme combinations. Finally, 32 different pEY10 DNA fingerprints were found out of 57 isolates examined. Overall the results indicate that of F. oxysporum f. sp. canariensis forms a single clonal lineage with a low to moderate level of genetic diversity.