Seed-feeding Nysius insects (Hemiptera: Lygaeidae) have a symbiotic association with distinct intracellular bacteria, “Candidatus Schneideria nysicola” (Gammaproteobacteria). Although many other hemipteran insect groups generally rely on bacterial symbionts that synthesize all ten essential amino acids lacking in their plant sap diets, the nutritional role of Schneideria in Nysius hosts that specialize on a more nutritionally complete seed-based diet has remained unknown. To determine the nutritional and functional capabilities of Schneideria, we sequenced the complete Schneideria genomes from three distantly related endemic Hawaiian Nysius seed bug species. The complete Schneideria genomes are highly conserved and perfectly syntenic among Hawaiian Nysius host species. Each circular chromosome is ∼0.57 Mb in size and encodes 537 protein-coding genes. They further exhibit a strong A + T nucleotide substitution bias with an average G + C nucleotide content of 29%. The predicted nutritional contribution of Schneideria includes four B vitamins and five of the ten essential amino acids that likely match its hosts’ seed-based diet. Disrupted and degraded genes in Schneideria suggests that Hawaiian lineages are undergoing continued gene losses observed in the smaller genomes of the other more ancient hemipteran symbionts.

中文翻译：

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夏威夷 Nysius 昆虫依赖于基因组减少的专性共生体，该共生体保留了离散的营养成分以匹配它们的植物种子饮食

以种子为食的 Nysius 昆虫（半翅目：Lygaeidae）与不同的细胞内细菌“Candidatus Schneideria nysicola”（Gammaproteobacteria）具有共生关系。尽管许多其他半翅目昆虫群体通常依赖细菌共生体来合成植物汁液饮食中缺乏的所有 10 种必需氨基酸，但 Schneideria 在专注于营养更完整的以种子为基础的饮食的 Nysius 宿主中的营养作用仍然未知。为了确定施奈德菌的营养和功能能力，我们对三个远缘夏威夷地方性 Nysius 种子虫物种的完整施奈德菌基因组进行了测序。完整的 Schneideria 基因组在夏威夷 Nysius 宿主物种中高度保守且完全同线。每个圆形染色体为～0。大小为 57 Mb，编码 537 个蛋白质编码基因。它们进一步表现出强烈的 A + T 核苷酸替代偏差，平均 G + C 核苷酸含量为 29%。施耐德氏菌的预测营养贡献包括四种 B 族维生素和十种必需氨基酸中的五种，可能与其宿主的以种子为基础的饮食相匹配。施耐德氏菌中的破坏和退化基因表明，夏威夷血统正在经历在其他更古老的半翅目共生体的较小基因组中观察到的持续基因丢失。