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“Candidatus Liberibacter europaeus” (Leu) is one of six currently known Liberibacter species. It is known primarily from pear and related species across Europe, and from Scotch broom and its associated psyllids in New Zealand (introduced from Britain). The psyllids were introduced to New Zealand as a biocontrol agent for broom and it is thought the bacterium may have been introduced as an endosymbiont of the psyllids. No symptoms in apple or pear trees have been reported, but mild symptoms can occur in broom. 16S and 16S–23S intergenic spacer region DNA sequences of this species are available from GenBank. Analysis of these sequences and associated ecological descriptions indicates the occurrence of two haplotypes, LeuA and LeuB, defined not only genetically but also by geographic range as well as by plant/psyllid host species composition. Liberibacter species are new to science and haplotype identifications enable historical accounts of relationships and spread to be generated.
Version 2 has a few minor sentence rewordings to clarify and read better. The specific sequences aligned and analysed are noted. The main change is to format it to a more easily and coherently readable form. The Nelson et al 2011 paper describing haplotypes of a related Liberibacter species suffered similar comments as this one but has subsequently been cited 35 times. In particular, biological differences are now being noted between the haplotypes beyond the obvious geographic range and host (insect/plant) species. This is intended to be the final version and I have no intention of submitting elsewhere. Version 1 was submitted to PeerJ but rejected, reviewer comments follow as per PeerJ requirements for revision of PrePrints.