|Sagaram, U - UNIVERSITY OF FLORIDA|
|Kim, J - UNIVERSITY OF FLORIDA|
|Wang, N - UNIVERSITY OF FLORIDA|
Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 25, 2008
Publication Date: June 15, 2008
Citation: Sagaram, U.S., Tatineni, S., Kim, J., Wang, N. 2008. In planta distribution and quantification of Asiatic strain of citrus Huanglongbing pathogen. American Phytopathological Society Annual Meeting. Phytopathology 98: S128 (2008). Technical Abstract: Huanglongbing is one of the most devastating diseases caused by an uncultured phloem limited bacterium, Candidatus Liberibacter spp. In this study, a combination of traditional and real-time PCR targeting the putative DNA polymerase and 16S rDNA sequence, respectively, were used to examine the distribution and movement of the Asiatic strain (Las) of citrus Huanglongbing in the infected citrus tree. We found that Las was distributed in bark tissue, leaf midrib, roots, and different floral and fruit parts, but not in endosperm and embryo, of infected citrus trees. In addition, quantitative real time PCR was used for quantification of the Las in citrus leaf midribs, roots, periwinkle leaves and psyllids. Quantification analysis of the HLB bacterium indicated that Las concentrations varied widely among different tissues of the citrus tree. A relatively high concentration of Las was observed in fruit peduncles. Our data from greenhouse infected plants indicated that Las was systemically transmitted from infection site to different parts of the plant. Our study also indicated that a minimum bacterial concentration is required for HLB symptom development. Understanding the distribution and movement of the HLB bacterium inside an individual citrus tree is critical for discerning its virulence mechanism and to develop management strategies for HLB.