IACPH 2024 - Oral Paper - Valeria Trivellone

Oral scientific presentation on "INSIGHTS INTO ECO-EVOLUTIONARY DYNAMICS OF HEMIPTERA PHYTOPLASMA ASSOCIATIONS" delivered by Valeria Trivellone of the Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA, during the 17th International Auchenorrhyncha Congress and 13th International Workshop on Leafhoppers and Planthoppers of Economic Importance held on 1 - 5 April 2024 on SEARCA, University of the Philippines Los Baños, Laguna, Philippines.

Previous research on the evolution of pathogenicity in plant pathogens associated with major economic losses of agricultural crops has emphasized the idea that pathogen-host associations are shaped by conspeciation events, which lock the pathogens into an evolutionary dead-end pathway toward extreme specialization. However, there is substantial evidence supporting the roles of other processes that may lead to new associations, especially host switching. Vector-borne plant pathogens retain the extraordinary ability to colonize host species belonging to different kingdoms (e.g., insects and plants) at different stages within their life cycle through a jump-fit-colonize dynamic. This ability may have contributed to evolution of relationships between bacteria and their plant and arthropod hosts that may vary along a parasitism–commensalism continuum. Phytoplasmas are a diverse group of vector-borne parasites that inhabit the phloem of vascular plants and are spread from plant to plant by sap-feeding hemipteran insects. Using previously available data, we present a cophylogentic analysis and ancestral area range reconstruction of the phytoplasma-hemipteran insect associations to elucidate possible ecological and evolutionary processes that may have contributed to shaping the past and present phytoplasma-hemipteran vector associations worldwide. Our results suggest that the observed association between clade 16SrX and Psylloidea (Sternorrhyncha) may be the result either of isolation or environmental stability, possibly leading to specialization, during or immediately after their concurrent emergence (~ 97MYA). However, host-switching events may have driven multiple colonization events during the Cretaceous and Cenozoic with expansion of the host repertoire to Cixiidae and Dictyopharidae.