Haplotypes of “Candidatus Liberibacter solanacearum” suggest long-standing separation

Abstract

Three haplotypes of the recently discovered bacterium species "Candidatus Liberibacter solanacearum" are described and related to geographic ranges. The first two are associated with Zebra Chip/Psyllid Yellows of potatoes and other solanaceous plants, vectored by the tomato/potato psyllid Bactericera cockerelli in North and Central America and New Zealand. The third is associated with diseased carrots in Finland and vectored by the carrot psyllid Trioza apicalis. The haplotypes are described by SNPs on the 16s rRNA, 16s/23s ISR and 50s rplJ and rplL ribosomal protein genes. These SNPs are inherited as a package across the three genes. Haplotype "a" has been found primarily from Honduras and Guatemala through western Mexico to Arizona and California, and in New Zealand. Haplotype "b" is currently known from eastern Mexico and northwards through Texas to south central Washington. These haplotypes show some range overlap in Texas, Kansas and Nebraska. The haplotypes are not yet known to elicit biological differences in the plant or insect hosts. These apparently stable haplotypes suggest separate bacterial populations of long standing.

Haplotypes of “Candidatus Liberibacter europaeus” also separate by geography and host species

“…L. solanacearum" (Lso) is a Liberibacter species vectored by a number of species of Triozid psyllids and causes considerable damage in both Solanaceae and Apiaceae crops in North America and western Europe respectively (Munyaneza, 2013). Five haplotypes have now been described within this bacterial species through SNPs on the 16S, 16S-23S intergenic spacer region and 50S genes (Nelson, Fisher & Munyaneza, 2011;Teresani et al, 2014), as well as describing differences in geographic and plant/insect host ranges. Haplotyping has a number of important disease management aspects, for example as a means of aiding in determining the source of incursions (Nelson et al, 2014;Thomas et al, 2011), or apparent differences in host responses (Rashed et al, 2014).…”

Vector mediated transmission of Candidatus Liberibacter solanacearum and epidemiological consequences

“…RNA genes (Nelson et al, 2011(Nelson et al, , 2012(Nelson et al, , 2013Teresani et al, 2014). Lso haplotypes are distributed in different geographical regions and have been designated as A, B, C, D, E, according to the order they have been described.…”

“…Haplotype A has been detected in solanaceous crops in the United States of America, Mexico, Honduras, Guatemala and New Zealand. Haplotype B overlaps with haplotype A in Solanaceae in the United States of America and Mexico (Nelson et al, 2011). Haplotypes C, D, E have been associated to Apiaceae crops in Europe (Nelson et al, 2012).…”

“…Notably, different psyllid species transmit different haplotypes of Lso in different geographical areas and to different host plants (Nelson et al, 2011). In the Americas and New Zealand, Lso haplotypes A and B are transmitted to plants in Solanaceae by the potato psyllid Bactericera cockerelli Šulc (Nelson et al, 2011).…”

“…In the Americas and New Zealand, Lso haplotypes A and B are transmitted to plants in Solanaceae by the potato psyllid Bactericera cockerelli Šulc (Nelson et al, 2011). In Europe and North Africa, Lso haplotype C is transmitted by Trioza apicalis Foerster, 1848 (Nissinen et al, 2014).…”