题目：Biodiversity of Bacterial Symbionts of Ciliates: state of the art and future trends

报告人：Giulio Petroni，意大利比萨大学动物学正教授

主持人：范鑫鹏 副教授

报告时间：2018年11月29日 13:30

报告地点：闵行校区生科院534小会议室

 

报告人简介：Giulio Petroni，意大利比萨大学（University of Pisa）动物学正教授。研究方向包括：原生动物系统分类学与细胞学、纤毛虫-细菌共生系统及宿主与共生体互作机制、微生物微管蛋白进化和功能基因组学、环境微生物学等。已主持多项意大利国家重大利益项目计划和欧盟国际科研人才交流计划。曾获意大利动物联盟(UZI)“Renzo Nobili”奖，曾担任欧洲科术合作计划（COST）管理委员会委员。在原生动物学及微生物学领域的专业期刊上发表论文70多篇，在Proc. Natl. Acad. Sci.和Nuc. Acid Res.等高水平杂志上发表论文多篇。

 

报告摘要: The description of novel taxa of bacterial symbionts of ciliates boosted with the turning of the century. Molecular biology techniques integrated in the full cycle rRNA approach represented the technical basis of this renaissance of study on symbiont of ciliates that brought to the description of more than 15 new symbiont genera. In this talk, a critical review of recent literature on the topic will be provided. Starting from the traditional de Bary's definition of symbiosis as "the living together of unlike organisms", I will first briefly present examples of clearly mutualistic interactions such as Polynucleobacter, necessary for the survival of freshwater Euplotes, or the methanogenic Archaea symbionts of anaerobic ciliates. Later on, I will pass to relationships that are more difficult to define in terms of benefit/harm for the host. Indeed, I will focus on recently discovered biodiversity within two related groups of obligatory symbionts: Rickettsiales and Holosporales, encompassing also mild to severe human and vertebrate pathogens. Especially for what concerns Rickettsiales, results from the last ten years dramatically changed our view on this bacterial order. Once considered as typical endosymbionts/pathogens of arthropods and vertebrates, it is now known that the vast majority of the biodiversity of Rickettsiales is hosted by aquatic organisms, among which many are represented by protists, in general, and ciliates, in particular. In the very last years, also genomic data on bacterial symbionts of ciliates started to be produced. Genomic study on symbionts will surely represent the future of the field, and will help shedding light also on functional interaction between host and symbiont, a topic that, probably due to the recent focus on molecular characterizations, received less attention in the last years. In conclusion, present data suggest that we know only the tip of ciliate symbionts' diversity and many years will be necessary to properly describe it also in functional terms.