Certain genes are unique to phage genomes, Erlotinib and non-phage genes were not typically found to be present between phage genes in an inserted phage. From a genomic standpoint, prophage regions are also indicated by regions not present in closely related species, as well as long strings of unidentified proteins in similar orientation . From the above criteria, the locations and boundaries of two prophages in L. crescens were predicted to extend from base pair 523,789-564,039 in prophage LC1 and from base pair 848,435-886,798 in prophage LC2. Unlike the two prophages in Candidatus L. asiaticus, the prophages in L. crescens were not homologues, sharing only short (<1,000 bp) regions of moderate similarity, determined through Wise2 alignment . Additionally, the prophages in L.
crescens were not found in Candidatus L. asiaticus. Homology was inferred through alignment by the progressiveMauve algorithm  (Figures 3–5).5). While the SC1 phage in Candidatus L. asiaticus is known to enter a lytic cycle in the phloem of citrus, the lifecycles of the prophages in L. crescens have yet to be explored experimentally . Figure 3 Circular genomic map of L. crescens BT-1. From outside to the center: Genes on forward strand (colored by labeled COG categories), genes on reverse strand (colored by labeled COG categories), RNA genes (tRNA green, rRNA red), putative prophage regions, … Figure 5 Candidatus L. solanacearum and Candidatus L. asiaticus. Signifies that prophages in L. crescens are not homologous to each other or to the tandem prophage region in Candidatus L. asiaticus.
Figure 4 Whole sequence alignment of phage regions between L. crescens and Candidatus L. asiaticus. The two prophage regions Candidatus L. solanacearum are homologous, and both share higher similarity with the prophage region in Candidatus L. asiaticus. Graphical … Interestingly, the same zinc ABC transporter mentioned above is present in the LC2 region. Prophage insertions have been known to add functions to hosts, making the host more competitive . In addition to metabolic variation, the differences in extra-chromosomal genomic content between species of the Liberibacter genus may also be indicative of the virulence and fastidious nature of the genus. Conclusion Liberibacter crescens BT-1 is the first member of the Liberibacter genus to be cultured.
The complete genome sequences of Candidatus L. asiaticus and Candidatus L. solanacearum have been determined through isolation from the disease vectors [7,9], Drug_discovery but any attempt to culture these species typically depends on employing a co-culture with insect or plant host cells . Genomic sequencing of L. crescens BT-1 was performed in an attempt to find possible indications for virulence in Candidatus L. asiaticus and Candidatus L.