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United States Department of Agriculture

Agricultural Research Service

Research Project: Improved Utilization of Ag. Products through Identification of Nitrogen-containing Bioactive Components Important to Quality & Human Health

Location: Healthy Processed Foods Research

Title: Metabolomic analysis of citrus infection by Candidatus Liberibacter reveals insight into pathogenicity

Authors
item Slisz, Anne -
item Breksa, Andrew
item Mishchuk, Darya -
item McCollum, Thomas
item Slupsky, Carolyn -

Submitted to: Journal of Proteome Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 2, 2012
Publication Date: June 15, 2012
Repository URL: http://dx.doi.org/10.1021/pr300350x
Citation: Slisz, A., Breksa III, A.P., Mishchuk, D.O., Mccollum, T.G., Slupsky, C.M. 2012. Metabolomic analysis of citrus infection by Candidatus Liberibacter reveals insight into pathogenicity. Journal of Proteome Research. DOI: abs/10.1021/pr300350x.

Interpretive Summary: Huanglongbing (HLB), considered the most serious citrus disease in the world, is associated with the non-culturable bacterium Candidatus Liberibacter asiaticus (Las). In order to evaluate the pathogen's influence on fruit quality and to gain further insight into the pathogenesis of the disease, a 1H nuclear magnetic resonance (NMR) metabolomics investigation was undertaken, complemented with physicochemical and analyte-specific analyses. Using metabolomic data coupled with statistical analysis, we demonstrate differing metabolic profiles in oranges from Las+ and Las- trees, and discuss how Las may be able to evade citrus defense responses.

Technical Abstract: Huanglongbing (HLB), considered the most serious citrus disease in the world, is associated with the non-culturable bacterium Candidatus Liberibacter asiaticus (Las). Infection by the pathogen leads to reduced plant vigor and productivity, and ultimately results in death of the infected tree. Additionally, it can take up to two years following initial infection before outward symptoms, many them not specific to the disease, become apparent, thus making detection difficult. The existing knowledge gap in our understanding of the pathogen and the pathogenesis associated with HLB has stymied the development of treatments and methods to mitigate the pathogen's influence. In order to evaluate the pathogen's influence on fruit quality and to gain further insight into the pathogenesis of the disease, a 1H nuclear magnetic resonance (NMR) metabolomics investigation was undertaken, complemented with physicochemical and analyte-specific analyses. Comparison of the juice obtained from oranges gathered from Las+ and Las- trees revealed significant differences in the concentrations of glucose, sucrose, amino and organic acids, limonin glucoside, and limonin. With the exception of phenylalanine, limonin glucoside, and limonin, oranges from Las+ trees had lower concentrations of sugars and amino acids compared to fruit from Las- trees. Using metabolomic data coupled with statistical analysis, we demonstrate differing metabolic profiles in oranges from Las+ and Las- trees, and discuss how Las may be able to evade citrus defense responses.

Last Modified: 11/25/2014
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