[G] Oral presentations in English

[G-14] On the vertical transmission of the cockroach endosymbiont Blattabacterium via ovarial infection in the German cockroach Blattella germanica

◯Tomohito Noda^1,2, Minoru Moriyama², Takema Fukatsu^1,2,3 (1. The University of Tokyo, 2. AIST, 3. University of Tsukuba)

Many organisms with symbiotic microorganisms have developed complex vertical transmission mechanisms, which comprise a pivotal element in the evolution of intimate symbiotic relationships with microorganisms. One such case is the cockroach-Blattabacterium endosymbiosis, in which the bacterial symbiont is vertically transmitted via ovarial infection. While some classical histological descriptions and electron microscopic observations have been reported, the full picture of the infection dynamics remains elusive. In this study, we present a detailed description of the symbiont transmission pathway by visualizing Blattabacterium cells in the ovary throughout the life span of the German cockroach Blattella germanica using FISH detection. We found that ovarial infection occurs only during larval stages and is not observed in adult insects. These results represent a key element for understanding the endosymbiotic relationship in cockroaches, as well as aid in further investigation of the evolutionary adaptations required for insect-microbe endosymbiosis.