Speaker: Prof. Piotr Łukasik, Jagiellonian University, Kraków [website]

Title: The uncharted territory: the extreme evolutionary processes in planthopper symbioses

Abstract

Ancient heritable nutritional endosymbiotic bacteria of sap-sucking hemipterans are known for their highly reduced genomes. Despite elevated sequence evolutionary rates, these genomes have typically retained conserved contents, organization, and structure for hundreds of millions of years. But this is not always the case: in many host lines, after a period of stability, these tiny genomes experienced dramatic changes, including further substantial reduction, rearrangements, fragmentation, and division into complexes of genetically and cytologically distinct but interdependent lineages that together function as the single ancestral symbiont.

Our research group has explored these symbioses across the taxonomic diversity of the hemipteran suborder Auchenorrhyncha, with particular emphasis on one of their clades - planthoppers. During my talk, I will outline the broad evolutionary patterns and processes related to their symbioses, introduce some of the most extreme cases including the tiniest known bacterial genomes, and explore the primary drivers of genomic reduction.