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United States Department of Agriculture

Agricultural Research Service

Research Project: EPIDEMIOLOGY AND MANAGEMENT OF XYLELLA FASTIDIOSA (XF) AND OTHER EXOTIC AND INVASIVE DISEASES AND INSECT PESTS

Location: Crop Diseases, Pests and Genetics

Title: The complete genome sequence of ‘Candidatus Liberibacter solanacearum’, the bacterium associated with potato Zebra Chip disease

Authors
item LIN, HONG
item Lou, Binghai -
item Glynn, Jonathan
item Doddapaneni, Harshavardhan -
item Civerolo, Edwin
item Chen, Chuanwu -
item DUAN, PING
item Zhou, Lijuan -
item ARMSTRONG, CHERYL

Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 17, 2011
Publication Date: April 28, 2011
Citation: Lin, H., Lou, B., Glynn, J.M., Doddapaneni, H., Civerolo, E.L., Chen, C., Duan, Y., Zhou, L., Vahling, C.M. 2011. The complete genome sequence of ‘Candidatus Liberibacter solanacearum’, the bacterium associated with potato Zebra Chip disease. PLoS One. 6(4):e19135. (doi:10.1371/journal.pone.0019135).

Interpretive Summary: Zebra Chip (ZC) is an important plant disease in potatoes which causes aboveground decline and results in unusable tubers. This disease has led to multi-million dollar losses for growers in the central and western United States over the past decade and impacts the livelihood of potato farmers in Mexico and New Zealand. ZC is caused by the presumptive agent named as ‘Candidatus Liberibacter solanacearum’ (Lso), a fastidious alpha-proteobacterium. Naturally, ZC-associated Liberibacter is transmitted by the phloem-feeding potato psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been impeded by the fact that the bacterium is unculturable. Here the complete sequence of the 1.26 Mbp metagenome of Lso based on DNA isolated from potato psyllids is presented. Taxonomically, Lso is related to ‘Candidatus Liberibacter asiaticus' (Las), the bacterium associated with citrus huanglongbing (HLB). Comparative genome analyses, however, indicated that there were considerable genome rearrangements between the Lso and Las genomes. In addition, several gene gains/losses were evident in the Lso genome compared to the sequenced and annotated HLB-associated Las genome. However, both Lso and Las share common ancestral pathways such as amino acid and vitamin biosynthesis as well as the features commonly shared with several pathogenic microbes. The complete genome sequence of Lso will facilitate development of genome-based disease control strategies.

Technical Abstract: Zebra Chip (ZC) is an emerging plant disease that causes aboveground decline of potato shoots and generally results in unusable tubers. This disease has led to multi-million dollar losses for growers in the central and western United States over the past decade and impacts the livelihood of potato farmers in Mexico and New Zealand. ZC is associated with ‘Candidatus Liberibacter solanacearum’ (Lso), a fastidious alpha-proteobacterium that is transmitted by a phloem-feeding psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been hampered by a lack of robust in vitro culture methods and paucity of genome sequence information for Lso. Here the complete sequence of the 1.26 Mbp metagenome of Lso is presented, based on DNA isolated from potato psyllids. The coding inventory of the Lso genome was analyzed and compared to related Rhizobiaceae to better understand Lso physiology and identify potential targets to develop improved treatment strategies. This analysis revealed a number of unique transporters and pathways, all potentially contributing to ZC pathogenesis. Some of these factors may have been acquired through horizontal gene transfer. Taxonomically, Lso is related to ‘Candidatus Liberibacter asiaticus' (Las), the presumptive causative agent of citrus huanglongbing (HLB). However, many genome rearrangements and several gene gains/losses were evident in the Lso genome compared to the sequenced and annotated HLB-associated Las genome. Relative to Las, Lso has lost some capacity for nucleic acid modification, retained ancestral pathways for amino acid and vitamin biosynthesis, and gained a high-affinity iron transport system characteristic of several pathogenic microbes. The complete genome sequences of Lso will facilitate development of genome-based disease control strategies.

Last Modified: 9/29/2014
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