Complete genome sequence of citrus huanglongbing bacterium, 'Candidatus Liberibacter asiaticus' obtained through metagenomics.

TitleComplete genome sequence of citrus huanglongbing bacterium, 'Candidatus Liberibacter asiaticus' obtained through metagenomics.
Publication TypeJournal Article
Year of Publication2009
AuthorsDuan, Y, Zhou, L, Hall, DG, Li, W, Doddapaneni, HV, Lin, H, Liu, L, Vahling, CM, Gabriel, DW, Williams, KP, Dickerman, A, Sun, Y, Gottwald, T
JournalMol Plant Microbe Interact
Volume22
Issue8
Pagination1011-20
Date Published2009 Aug
ISSN0894-0282
KeywordsAnimals, Bacterial Proteins, Carrier Proteins, Citrus, Genome, Bacterial, Genomics, Hemiptera, Molecular Sequence Data, Phylogeny, Rhizobiaceae, Sequence Analysis, DNA, Symbiosis
Abstract

Citrus huanglongbing is the most destructive disease of citrus worldwide. It is spread by citrus psyllids and is associated with a low-titer, phloem-limited infection by any of three uncultured species of alpha-Proteobacteria, 'Candidatus Liberibacter asiaticus', 'Ca. L. americanus', and 'Ca. L. africanus'. A complete circular 'Ca. L. asiaticus' genome has been obtained by metagenomics, using the DNA extracted from a single 'Ca. L. asiaticus'-infected psyllid. The 1.23-Mb genome has an average 36.5% GC content. Annotation revealed a high percentage of genes involved in both cell motility (4.5%) and active transport in general (8.0%), which may contribute to its virulence. 'Ca. L. asiaticus' appears to have a limited ability for aerobic respiration and is likely auxotrophic for at least five amino acids. Consistent with its intracellular nature, 'Ca. L. asiaticus' lacks type III and type IV secretion systems as well as typical free-living or plant-colonizing extracellular degradative enzymes. 'Ca. L. asiaticus' appears to have all type I secretion system genes needed for both multidrug efflux and toxin effector secretion. Multi-protein phylogenetic analysis confirmed 'Ca. L. asiaticus' as an early-branching and highly divergent member of the family Rhizobiaceae. This is the first genome sequence of an uncultured alpha-proteobacteria that is both an intracellular plant pathogen and insect symbiont.

DOI10.1094/MPMI-22-8-1011
Alternate JournalMol. Plant Microbe Interact.
PubMed ID19589076