“Candidatus Sulcia muelleri” (Sulcia) is a diverse lineage of intracellular nutritional endosymbiotic bacteria strictly associated with auchenorrhynchous hemipteran insects. Sulcia has undergone long-term codiversification with its insect hosts but the phylogeny of these endosymbionts, their relationships to other bacteria, and the extent of their occurrence within various groups of Auchenorrhyncha remain inadequately explored. Comprehensive phylogenetic analyses of Sulcia and related bacteria were performed to elucidate its position relative to other members of Phylum Bacteroidetes and the degree of congruence to the phylogeny of its auchenorrhynchous hosts. Maximum likelihood (ML) and maximum parsimony (MP) analyses of Flavobacteriales based on genomic data from 182 bacterial strains recover a monophyletic Sulcia within a larger clade of flavobacterial insect endosymbionts, closely related to Weeksellaceae. Molecular divergence time analysis of Sulcia dates the origin of Sulcia at approximately 339.95 million years ago (Myr) and the initial divergence within Sulcia at approximately 256.91 Myr but these are considered underestimates due to the tendency for endosymbionts to evolve at higher rates compared to their free-living relatives. Screening of 96 recently sequenced hemipteran transcriptomes revealed that 73 of these species, all Auchenorrhyncha, harbored Sulcia. Phylogenetic analysis of 131 orthologous genes plus 16S rRNA for 101 Sulcia strains, representing six fulgoroid families and all the families of Cicadomorpha except Tettigarctidae, recover largely congruent phylogenies between Sulcia and Auchenorrhyncha. The phylogeny of Sulcia strongly supports the superfamily relationships Fulgoroidea + (Cicadoidea + (Cercopoidea + Membracoidea)). Relationships within individual superfamilies are also largely concordant, with the few areas of apparent incongruence between Sulcia and insect genes attributable to low branch support in one or both datasets. These results suggest that analysis of Sulcia phylogeny may contribute to resolution of contentious aspects of Auchenorrhyncha phylogeny.

中文翻译：

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黄杆菌昆虫营养内共生体的系统基因组学对 Auchenorrhyncha 系统发育的影响

“ Candidatus Sulcia muelleri” (Sulcia) 是一种细胞内营养内共生细菌的多样化谱系，与原喙半翅目昆虫密切相关。Sulcia 与其昆虫宿主经历了长期的共同多样化，但这些内共生菌的系统发育、它们与其他细菌的关系以及它们在各种 Auchenorrhyncha 群中的出现程度仍未得到充分探索。对苏尔西亚和相关细菌进行了全面的系统发育分析，以阐明其相对于拟杆菌门其他成员的位置以及与其原喙宿主系统发育的一致性程度。黄杆菌目的最大似然 (ML) 和最大简约 (MP) 分析基于来自 182 种细菌菌株的基因组数据，在与 Weeksellaceae 密切相关的黄杆菌昆虫内共生菌的更大进化枝中恢复了单系Sulcia。Sulcia 的分子分歧时间分析将 Sulcia 的起源追溯到大约 3.3995 亿年前 (Myr)，Sulcia 内部的初始分歧大约在 256.91 Myr，但由于内共生菌与自由菌相比，内共生菌的进化速率更高，因此这些被认为低估了- 活着的亲戚。对 96 个最近测序的半翅目转录组的筛选显示，这些物种中的 73 个，全部是 Auchenorrhyncha，都含有苏尔西亚。131个直系同源基因加16S rRNA的系统发育分析对于 101 个 Sulcia 菌株，代表六个 fulgoroid 家族和除 Tettigarctidae 之外的所有 Cicadomorpha 家族，恢复了 Sulcia 和 Auchenorrhyncha 之间的基本一致的系统发育。Sulcia 的系统发育强烈支持超科关系 Fulgoroidea + (Cicadoidea + (Cercopoidea + Membracoidea))。单个超家族内部的关系在很大程度上也是一致的，Sulcia 和昆虫基因之间的少数明显不一致的区域可归因于一个或两个数据集中的低分支支持。这些结果表明，Sulcia 系统发育的分析可能有助于解决 Auchenorrhyncha 系统发育的有争议的方面。