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ARS Home Northeast Area Beltsville, Maryland (BARC) Beltsville Agricultural Research Center Molecular Plant Pathology Laboratory Docs





- Spiroplasma and Bees
- Spiroplasma kunkelli genome sequencing project
- Spiroplasma kunkelli plasmid
- Florida Juice Commision
- University of Florida
- Sunkist kid's stuff
- The Ultimate Citrus Page
- California Citrus Research Board
- Citrus from Down Under- The Australian Citrus Growers, Inc.
- Texas Citrus

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 Citrus Research written in colorful graphics      Now a part of the Molcular Plant Pathology Laboratory Orange 3D horizontal line fading to white on right side  Citrus Quarantine Facility Yes, there are orange trees in Maryland! History of the Facility   Research at the FacilityImage of 2 citrus trees one green and alive the other all leaves are brown, a symptom of decline    A comparison between a mild CTV strain (left)a healthy plant (middle) and a severe CTV strain (right)  Recent accomplishments Citrus Cankerimage of a citrus leaf with citrus canker **Pathogen detection**. A U.S. patent has been awarded for the development of improved detection methods forXanthomonas axonopodispv. citri, the causal agent of Citrus Bacterial Canker Disease. This assay has already been used to confirm outbreaks of this serious disease in Florida, Argentina and Australia. The PCR based assay for this pathogen developed in our laboratory is currently the most sensitive and best available.  Citrus Variegated Chlorosis Xylella fastidiosa  Plant showing streaked bright yellow chlorosis a symptom of CVCSymptoms of Citrus Variegated Chlorosis disease, caused by the Gram negative bacterium Xyllella fastidiosa, on a sweet orange tree. In addition to the bright chlorosis, the disease also causes stunting and dramatic yield losses. Detection of the pathogen Xylella fastidiosa in single leaf petioles (upper half of gel) and in single insect vectors, Oncometopia nigricans. The bright bands on this agarose gel are DNA fragments specificAn image of a gel showing bright bands where samples are positive for CVC to Xylella fastidiosa amplified by the Polymerase Chain Reaction. This is the most sensitive and specific assay available for this pathogen. Because of the importance of the citrus variegated chlorosis disease, Xylella fastidiosa recently became the first plant pathogen to have the complete nucleotide sequence of its genome determined. The sequencing project was carried out in Brazil. We have also developed a diagnostic assay for this virus which can be used to protect the U.S. industry from this disease.  Dr. John Hartung  Cristina Paul


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