Analysis of Candidatus Liberibacter asiaticus Proteome

Qian Cong and Nick V. Grishin


Candidatus Liberibacter asiaticus (C. L. asiaticus) is a Gram negative bacterium and is the pathogen of Citrus greening (also called huanglongbing). The ranking Candidatus is assigned to this bacterium because it cannot be maintained in bacterial culture. In nature, the bacteria utilize piercing-sucking insects, psyllid, as vectors and thus are transmitted among plants. Hosts of C. L. asiaticus include nearly all citrus species. In the plant, C. L. asiaticus resides exclusively in the phloem tissues and gradually chokes off the supply of nutrients throughout the plant, weakening the plant and eventually killing it. [1][2]

Researchers have been making effort to understand the mechanism of the disease [3][4][5] and to save citrus industry against the horrible disease [6][7]. However, difficulty in obtaining bacteria culture make it challenging to carry out experiments on C. L. Candidatus. Last year, the complete genome sequence [8] of C. L. asiaticus was obtained by Yongping Duan and his colleagues and careful analysis of the genome will provide insight into the pathogen and lead to development of methods to control the bacterium.

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Fig.1 Trees show the symptoms of Huanglongbing has yellow shoot.(Photo courtesy T.R. Gottwald and S.M. Garnsey) Fig.2 Symptoms of citrus greening on mandarin orange fruit.(Photo courtesy T.R. Gottwald and S.M. Garnsey) Fig.3 Asian citrus psyllid, Diaphorina citri Kuwayama.(Image:David Hall, USDA-ARS, Ft. Pierce , FL)

In this website, we present our results of structure and function prediction on the proteome of C. L. asiaticus. For each protein, we gathered important information from various sources, predicted local sequence features, analyzed the domain achietecture, provided structure models and predicted the function based on its relationship to known protein and protein family. All the predictions were obtained by applying multiple automatic programs followed by manually curation of the results. More importantly, we identified several virulence factors of this bacteria. This website may help us to understand the physiology of the bacteria and the mechanism of citrus greening and serve as a reference for further experimental study on the bacteria and the disease.

Description of the Database Protein Categories BLAST search the proteome


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