Abstract
Over the last century, repeated emergence events within the Candidatus Liberibacter taxon have produced pathogens with devastating effects. Presently, our knowledge of Ca. Liberibacter diversity, host associations, and interactions with vectors is limited due to a focus on studying this taxon within crops. But to understand traits associated with pathogen emergence it is essential to study pathogen diversity in wild vegetation as well. Here, we explore historical native host plant associations and diversity of the cosmopolitan species, Ca. L. psyllaurous, also known as Ca. L. solanacearum, which is associated with psyllid yellows disease and zebra chip disease, especially in potato. We screened tissue from herbarium samples of three native solanaceous plants collected near potato-growing regions throughout Southern California over the last century. This screening revealed a new haplotype of Ca. L. psyllaurous (G), which, based on our sampling, has been present in the U.S. since at least 1970. Phylogenetic analysis of this new haplotype suggests that it may be closely related to a newly emerged North American haplotype (F) associated with zebra chip disease in potatoes. Our results demonstrate the value of herbarium sampling for discovering novel Ca. Liberibacter haplotypes not previously associated with disease in crops.
Highlights
Over the last century, repeated emergence events within the Candidatus Liberibacter taxon have produced pathogens with devastating effects
Herbarium specimens dating back to 1910 that were collected throughout California and other southwestern states were acquired from the University of California, Riverside’s Herbarium
Using herbarium specimens of native Solanaceae that were collected over the last century, we identified a new Ca
Summary
Over the last century, repeated emergence events within the Candidatus Liberibacter taxon have produced pathogens with devastating effects. Liberibacter species that associate with plants without being pathogenic, as well as species that may only reside and replicate within psyllid hosts This knowledge gap can only be addressed by increasing efforts to perform diagnostic and genetic characterization studies using historical specimens and sampling in unmanaged habitats[5,11]. Such approaches are yielding a wealth of information on the diversity and epidemiology of other plant pathogen taxa across different landscape types[5,7,12,13,14,15,16]. L. psyllaurous haplotypes are described throughout North and Central America, Europe, and New Zealand (Fig. 1)[4,9,24,25,26,27,28,29,30,31,32,33,34]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
