Location: Subtropical Plant Pathology Research
2011 Annual Report
This is the last year of this project. A complete circular genome of Candidatus Liberibacter asiaticus was obtained using a metagenomics approach and published in MPMI 22:1011-1020, 2009. In collaboration with USDA-ARS in Parlier, California, we have obtained and published a complete genome sequence of Ca. L. psyllaurous with ca.1.25Mb. All bacterial artificial chromosome (BAC) clones of Las were sequenced, and some new sequences will be added to the published genome.
We have characterized the adenosine triphosphate (ATP) translocase from Las and proved its function using a heterologous E. coli system. This data was published in J. Bacteriol. 192:834-840, 2010. We are currently developing an antibody-based "drug" to target this protein, aimed at disrupting ATP import, which may be important for its survival. We have also characterized the individual genes of two putative zinc operons in Las, confirming only one operon responsible for zinc uptake.
Progress on culture of Las bacterium in vitro has been made. Up to 1,000,000 cells/ml were obtained within 48 hrs based on quantitative polymerase chain reaction (qPCR) estimation. The Las cells number in the cultures were staggering and decline when they reached to Ct value 22.00 (16S rDNA-based RT-PCR) in liquid media. We are looking into factors affecting further growth.