Miao Yun-Heng, Xiao Jin-Hua, Huang Da-Wei
Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
College of Life Sciences, Nankai University, Tianjin, China.
Front Microbiol. 2020 Nov 13;11:595629. doi: 10.3389/fmicb.2020.595629. eCollection 2020.
The symbiosis system comprising eukaryotic hosts, intracellular bacterium , and temperate bacteriophages WO is widely spread through nearly half the number of arthropod species. The relationships between the three components of the system are extremely intricate. Even though the bacteriophage WO can have diverse influences on the ecology and evolution of , little is known about the distribution and evolution of the phages. To the best of our knowledge, this study is the first to report that in infected fig wasps (, , and ), the genomes of all the strains had only one cryptic WO prophage, which contained defects in the genomic structural modules. This phenomenon was contrary to the widely accepted understanding that with cryptic prophages usually possesses at least one intact WO prophage consisting of gene sequences of the head, baseplate, and tail modules, through which the prophage could form intact virions. In addition to the genetic structure features, the phylogenetic relationships of WO and also revealed that bacteriophage WO can horizontally spread among a certain genus or a group of insect hosts, nearly free from the restriction of the affiliation of . Combined with the vertical transmission along with , the wide spread of WO phages can be explained. Furthermore, the gender preference and functional module preference for transcriptional activity of the genes in cryptic WOs implied the antagonized coevolutionary pattern between WO prophages and their hosts.
由真核宿主、细胞内细菌和温和噬菌体WO组成的共生系统广泛分布于近半数的节肢动物物种中。该系统三个组成部分之间的关系极其复杂。尽管噬菌体WO对其生态和进化可能有多种影响，但对这些噬菌体的分布和进化却知之甚少。据我们所知，本研究首次报道，在受感染的榕小蜂（、和）中，所有菌株的基因组都只有一个隐蔽的WO前噬菌体，其基因组结构模块存在缺陷。这一现象与普遍接受的认识相反，即带有隐蔽前噬菌体的通常至少拥有一个由头部、基板和尾部模块的基因序列组成的完整WO前噬菌体，通过该前噬菌体可以形成完整的病毒粒子。除了遗传结构特征外，WO和的系统发育关系还表明，噬菌体WO可以在某一属或一组昆虫宿主之间横向传播，几乎不受宿主所属关系的限制。结合随宿主的垂直传播，可以解释WO噬菌体的广泛传播。此外，隐蔽WO中基因转录活性的性别偏好和功能模块偏好暗示了WO前噬菌体与其宿主之间的拮抗协同进化模式。
