Tikhe Chinmay V, Husseneder Claudia
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States.
Front Microbiol. 2018 Jan 4;8:2548. doi: 10.3389/fmicb.2017.02548. eCollection 2017.
The Formosan subterranean termite; is nutritionally dependent on the complex and diverse community of bacteria and protozoa in their gut. Although, there have been many studies to decipher the taxonomic and functional diversity of bacterial communities in the guts of termites, their bacteriophages remain unstudied. We sequenced the metavirome of the guts of Formosan subterranean termite workers to study the diversity of bacteriophages and other associated viruses. Results showed that the termites harbor a virome in their gut comprised of varied and previously unknown bacteriophages. Between 87-90% of the predicted dsDNA virus genes by Metavir showed similarity to the tailed bacteriophages . Many predicted genes from the virome matched to bacterial prophage regions. These data are suggestive of a virome dominated by temperate bacteriophages. We predicted the genomes of seven novel Caudovirales bacteriophages from the termite gut. Three of these predicted bacteriophage genomes were found in high proportions in all the three termite colonies tested. Two bacteriophages are predicted to infect endosymbiotic bacteria of the gut protozoa. The presence of these putative bacteriophages infecting endosymbionts of the gut protozoa, suggests a quadripartite relationship between the termites their symbiotic protozoa, endosymbiotic bacteria of the protozoa and their bacteriophages. Other than Caudovirales, ss-DNA virus related genes were also present in the termite gut. We predicted the genomes of 12 novel phages from the termite gut and seven of those possibly represent a new proposed subfamily. Circovirus like genomes were also assembled from the termite gut at lower relative abundance. We predicted 10 novel circovirus genomes in this study. Whether these circoviruses infect the termites remains elusive at the moment. The functional and taxonomical annotations suggest that the termites may harbor a core virome comprised of the bacteriophages infecting endosymbionts of the gut protozoa.
台湾地下白蚁在营养上依赖于其肠道中复杂多样的细菌和原生动物群落。尽管已经有许多研究来解读白蚁肠道中细菌群落的分类和功能多样性，但它们的噬菌体仍未得到研究。我们对白蚁工蚁肠道的宏病毒组进行了测序，以研究噬菌体和其他相关病毒的多样性。结果表明，白蚁肠道中存在一个病毒组，其中包含各种不同且此前未知的噬菌体。通过宏病毒预测的双链DNA病毒基因中，有87%-90%与有尾噬菌体具有相似性。病毒组中的许多预测基因与细菌前噬菌体区域相匹配。这些数据表明该病毒组以温和噬菌体为主。我们从白蚁肠道中预测了7种新型有尾噬菌体的基因组。在所测试的所有三个白蚁群体中，这7种预测的噬菌体基因组中有3种占比很高。预计有两种噬菌体感染肠道原生动物的内共生细菌。这些推测感染肠道原生动物内共生体的噬菌体的存在，表明白蚁与其共生原生动物、原生动物的内共生细菌及其噬菌体之间存在四方关系。除了有尾噬菌体，白蚁肠道中还存在与单链DNA病毒相关的基因。我们从白蚁肠道中预测了12种新型噬菌体的基因组，其中7种可能代表一个新提出的亚科。在白蚁肠道中还以较低的相对丰度组装出了圆环病毒样基因组。在本研究中我们预测了10种新型圆环病毒基因组。目前尚不清楚这些圆环病毒是否感染白蚁。功能和分类注释表明，白蚁可能拥有一个核心病毒组，该病毒组由感染肠道原生动物内共生体的噬菌体组成。
