Speaker: Prof. Tomonari Nozaki, Lab. Evolutionary Genomics, National Institute for Basic Biology (NIBB) [website]

Title: Polyploidy: an old but new perspective on the evolution of insect-bacteria partnerships

Abstract:

Many insects utilizing nutritionally deficient diets harbor bacterial endosymbionts in specialized organs called bacteriome, where both the host cells (=bacteriocytes) and the symbiont cells have been known to be polyploid for a long time. Considering the well-known effects of polyploidy such as cell enlargement and/or upregulation of gene expression, polyploidization of both may be critical in the maintenance of endosymbiosis. Furthermore, polyploidy can have particularly significant effects in the evolutionary fate of highly specialized bacterial symbionts with drastically reduced genomes. However, there are few studies focusing on the symbiosis-associated polyploidy. In order to elucidate the patterns of polyploidization, I have conducted ploidy analysis on the bacteriocytes of mainly aphids, and diverse bacterial symbionts. In this talk, I would like to discuss the functional and evolutionary significance of polyploidy in insect-bacterium symbiosis.