Evolution of symbiotic organs and endosymbionts in lygaeid stinkbugs
Evolution of symbiotic organs and endosymbionts in lygaeid stinkbugs
复制标题
DOI：
10.1038/ismej.2011.103
复制
发表时间：
2012-02-01
期刊：
影响因子：
11
通讯作者：
Fukatsu, Takema
中科院分区：
文献类型：
--
作者：
Matsuura, Yu;Kikuchi, Yoshitomo;Fukatsu, Takema
我们研究了 Nysius 属（昆虫纲：半翅目：Lygaeidae）种子虫的共生细菌。从代表 4 个物种、18 个种群和 281 个个体的所有样本中，一致地鉴定出了特定的细菌 16S rRNA 基因序列，这在 Gammaproteobacteria 中形成了一个独特的进化枝。原位杂交表明，该细菌位于细胞内的一对大细菌组中，这些细菌组形状不定形，颜色深红色，并与性腺相关。在成年女性的卵巢中，内共生体也位于每个胚层中部的“感染区”和每个卵母细胞前极的“共生体球”中，表明内共生体通过卵巢通道垂直传播。基于细菌 16S rRNA、groEL 和 gyrB 基因的系统发育分析一致支持 Nysius 内共生体的连贯单系性。与“Candidatus Kleidoceria schneideri”（Lygaeid bug Kleidocerys resedae 的细菌组相关内共生体）存在姐妹关系的可能性在统计上被拒绝，表明Lygaeidae 中内共生体的独立进化起源。内共生基因始终表现出AT偏向的核苷酸组成和加速的分子进化速率，并且内共生基因组的大小仅为0.6Mb。内共生体系统发育与宿主昆虫系统发育一致，表明在进化过程中存在严格的垂直传播和宿主-共生体共物种。基于这些结果，我们讨论了异翅目细菌组和内共生菌的进化，其中大多数成员与肠道共生细菌有关。建议将内共生菌分支命名为“Candidatus Schneideria nysicola”。 ISME 期刊 (2012) 6, 397-409； doi：10.1038/ismej.2011.103； 2011 年 8 月 4 日在线发布
We investigated seed bugs of the genus Nysius (Insecta: Hemiptera: Lygaeidae) for their symbiotic bacteria. From all the samples representing 4 species, 18 populations and 281 individuals, specific bacterial 16S rRNA gene sequences were consistently identified, which formed a distinct clade in the Gammaproteobacteria. In situ hybridization showed that the bacterium was endocellularly localized in a pair of large bacteriomes that were amorphous in shape, deep red in color, and in association with gonads. In the ovary of adult females, the endosymbiont was also localized in the 'infection zone' in the middle of each germarium and in the 'symbiont ball' at the anterior pole of each oocyte, indicating vertical transmission of the endosymbiont through the ovarial passage. Phylogenetic analyses based on bacterial 16S rRNA, groEL and gyrB genes consistently supported a coherent monophyly of the Nysius endosymbionts. The possibility of a sister relationship to 'Candidatus Kleidoceria schneideri', the bacteriome-associated endosymbiont of a lygaeid bug Kleidocerys resedae, was statistically rejected, indicating independent evolutionary origins of the endosymbionts in the Lygaeidae. The endosymbiont genes consistently exhibited AT-biased nucleotide compositions and accelerated rates of molecular evolution, and the endosymbiont genome was only 0.6Mb in size. The endosymbiont phylogeny was congruent with the host insect phylogeny, suggesting strict vertical transmission and host-symbiont co-speciation over evolutionary time. Based on these results, we discuss the evolution of bacteriomes and endosymbionts in the Heteroptera, most members of which are associated with gut symbiotic bacteria. The designation 'Candidatus Schneideria nysicola' is proposed for the endosymbiont clade. The ISME Journal (2012) 6, 397-409; doi: 10.1038/ismej.2011.103; published online 4 August 2011