Comparative genomics of a unique mutualistic apicomplexan

 描述（由申请人提供） 顶复门（Apicomplexa）是一组单细胞生物，长期以来一直被认为是一个完全寄生的分支。有许多在生态和医学上重要的顶复门，包括疟疾的病原体。然而，最近的证据揭示了一组互利的apicomplexans：海洋共生体属，肾菌属。肾霉菌在许多方面是不寻常的顶复门。首先，该属的成员只在一个海squares科中发现，在那里它们殖民于一个大的无管器官，肾囊。在该器官内，肾霉菌围绕尿酸盐和草酸钙沉积物。第二，与顶复门不同的是，肾菌属的细胞内含有细菌。这种互利共生的顶复门提供了一个独特的机会来解决有关顶复门生物学的重要问题。随着一个长期的目标，完全表征这一系统，在这里，我们建议集中比较肾菌基因组与其最近的亲戚，寄生属，sporidium。寄生于海鳞藻中的孢子虫和肾菌一样，也含有内共生细菌。同时栖息在肾霉菌属和黑孢子虫属的细菌的基因组也将被测序。数据生成将有一个假设，即细菌共生体可能提供关键的代谢功能，这种互利共生的进化重点。这些生物的基因组序列将为细胞学、显微镜和功能基因组研究提供基础。了解Apicomplexa生活方式转变的基因组特征将对确定哪些尚未被充分认识的基因组特征与毒力和寄生性相关产生重大影响。

 DESCRIPTION (provided by applicant) Apicomplexa is a group of unicellular organisms that has been long been considered an exclusively parasitic clade. There are many ecologically and medically important apicomplexans, including the causative agent of malaria. However, recent evidence has revealed one group of mutualistic apicomplexans: the marine symbiont genus, Nephromyces. Nephromyces are unusual apicomplexans in many ways. First, members of this genus are found exclusively inside one family of sea squirts, where they colonize a large, ductless organ, the renal sac. Within this organ, Nephromyces surround urate and calcium oxalate deposits. Second, unusually for apicomplexans, Nephromyces cells contain intracellular bacteria. This mutualistic apicomplexan offers a singular opportunity to address the important question about apicomplexan biology. With a long-term goal of completely characterizing this system, here we propose to focus on comparing the Nephromyces genome to its closest relative, the parasitic genus, Cardiosporidium. Members of Cardiosporidium parasitize a broad range of sea squirts yet, like Nephromyces, also contain endosymbiotic bacteria. The genomes of the bacteria inhabiting both Nephromyces and Cardiosporidium will also be sequenced. Data generation will have an emphasis on the hypothesis that the bacterial symbionts may provide key metabolic functions in the evolution of this mutualism. The genome sequences from these organisms will provide a stepping-stone for cytological, microscopy and functional genomic research. Understanding the genomic signatures of lifestyle transitions in Apicomplexa will have significant impact on determining which, as yet underappreciated, genomic features are correlated with virulence and parasitism.