Matarrita-Carranza Bernal, Moreira-Soto Rolando D, Murillo-Cruz Catalina, Mora Marielos, Currie Cameron R, Pinto-Tomas Adrián A
La Selva Biological Station, Organization for Tropical Studies, Heredia, Costa Rica.
Centro de Investigación en Estructuras Microscópicas, Universidad de Costa Rica, San José, Costa Rica.
Front Microbiol. 2017 Oct 17;8:2016. doi: 10.3389/fmicb.2017.02016. eCollection 2017.
The evolutionary success of hymenopteran insects has been associated with complex physiological and behavioral defense mechanisms against pathogens and parasites. Among these strategies are symbiotic associations between Hymenoptera and antibiotic-producing Actinobacteria, which provide protection to insect hosts. Herein, we examine associations between culturable Actinobacteria and 29 species of tropical hymenopteran insects that span five families, including Apidae (bees), Vespidae (wasps), and Formicidae (ants). In total, 197 Actinobacteria isolates were obtained from 22 of the 29 different insect species sampled. Through 16S rRNA gene sequences of 161 isolates, we show that 91% of the symbionts correspond to members of the genus with less common isolates belonging to and . Electron microscopy revealed the presence of filamentous bacteria with morphology in brood chambers of two different species of the eusocial wasps. Four fungal strains in the family Ophiocordycipitacea (Hypocreales) known to be specialized insect parasites were also isolated. Bioassay challenges between the Actinobacteria and their possible targeted pathogenic antagonist (both obtained from the same insect at the genus or species level) provide evidence that different Actinobacteria isolates produced antifungal activity, supporting the hypothesis of a defensive association between the insects and these microbe species. Finally, phylogenetic analysis of 16S rRNA and demonstrate the presence of five lineages associated with a broad range of insect species. Particularly our Clade I is of much interest as it is composed of one 16S rRNA phylotype repeatedly isolated from different insect groups in our sample. This phylotype corresponds to a previously described lineage of host-associated . These results suggest Clade I is a Hymenoptera host-associated lineage spanning several new insect taxa and ranging from the American temperate to the Neotropical region. Our work thus provides important insights into the widespread distribution of Actinobacteria and hymenopteran insects associations, while also pointing at novel resources that could be targeted for the discovery of active natural products with great potential in medical and biotechnological applications.
膜翅目昆虫在进化上的成功与针对病原体和寄生虫的复杂生理及行为防御机制有关。这些策略包括膜翅目与产生抗生素的放线菌之间的共生关系，这种关系为昆虫宿主提供保护。在此，我们研究了可培养放线菌与29种热带膜翅目昆虫之间的关系，这些昆虫分属于五个科，包括蜜蜂科（蜜蜂）、胡蜂科（黄蜂）和蚁科（蚂蚁）。总共从所采样的29种不同昆虫中的22种获得了197株放线菌分离株。通过对161株分离株的16S rRNA基因序列分析，我们发现91%的共生菌属于 属成员，较少见的分离株属于 和 属。电子显微镜显示，在两种不同的群居黄蜂的育幼室中存在具有 形态的丝状细菌。还分离出了已知为专门昆虫寄生虫的蛇孢虫草科（肉座菌目）的四种真菌菌株。放线菌与其可能的目标致病拮抗剂（均从同一昆虫的属或种水平获得）之间的生物测定挑战提供了证据，表明不同的放线菌分离株产生了抗真菌活性，支持了昆虫与这些微生物物种之间存在防御性关联的假设。最后，对16S rRNA和 的系统发育分析表明，存在与广泛的昆虫物种相关的五个 谱系。特别值得关注的是我们的进化枝I，因为它由一个16S rRNA系统型组成，该系统型在我们的样本中反复从不同昆虫群体中分离得到。这个系统型对应于先前描述的与宿主相关的 谱系。这些结果表明进化枝I是一个与膜翅目宿主相关的谱系，跨越几个新的昆虫分类群，范围从美国温带地区到新热带地区。因此，我们的工作为放线菌与膜翅目昆虫关联的广泛分布提供了重要见解，同时也指出了新的资源，这些资源可能成为发现具有医学和生物技术应用巨大潜力的活性天然产物的目标。
