New insights into the transovarial transmission of the symbiont Rickettsia in whiteflies  

作　　者：Hongwei Shan Yinquan Liu Junbo Luan Shusheng Liu 

机构地区：[1]Ministry ofAgriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects,Institute ofInsect Sciences,Zhejiang University,Hangzhou 310058,China [2]College of Plant Protection,Shenyang Agricultural University,Shenyang 110866,China

出　　处：《Science China(Life Sciences)》2021年第7期1174-1186,共13页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China(31772173)。

摘　　要：Endosymbiont transmission via eggs to future host generations has been recognized as the main strategy for its persistence in insect hosts;however,the mechanisms for transmission have yet to be elucidated.Here,we describe the dynamic locations of Rickettsia in the ovarioles and eggs during oogenesis and embryogenesis in a globally significant pest whitefly Bemisia tabaci.Field populations of the whitefly have a high prevalence of Rickettsia,and in all Rickettsia-infected individuals,the bacterium distributes in the body cavity of the host,especially in the midgut,fat body,hemocytes,hemolymph,and near bacteriocytes.The distribution of Rickettsia was subjected to dynamic changes in the ovary during oogenesis,and our ultrastructural observations indicated that the bacteria infect host ovarioles during early developmental stages via two routes:(i)invasion of the tropharium by endocytosis and then transmission into vitellarium via nutritive cord and(ii)entry into vitellarium by hijacking bacteriocyte translocation.Most of the Rickettsia are degraded in the oocyte cytoplasm in late-stage oogenesis.However,a few reside beneath the vitelline envelope of mature eggs,spread into the embryo,and proliferate during embryogenesis to sustain high-fidelity transmission to the next generation.Our findings provide novel insights into the maternal transmission underpinning the persistence and spread of insect symbionts.

关 键 词：Bemisia tabaci RICKETTSIA SYMBIOSIS vertical transmission 

分 类 号：S433.3[农业科学—农业昆虫与害虫防治]