Table_8_Core Mycobiome and Their Ecological Relevance in the Gut of Five Ips Bark Beetles (Coleoptera: Curculionidae: Scolytinae).XLS

Bark beetles are destructive forest pests considering their remarkable contribution to forest depletion. Their association with fungi is useful against the challenges of survival on the noxious and nutritionally limited substrate, i.e., conifer tissues. Fungal symbionts help the beetles in nutrient acquisition and detoxification of toxic tree secondary metabolites. Although gut is the prime location for food digestion and detoxification, limited information is available on gut-mycobiome of bark beetles. The present study screened the gut-mycobiont from six bark beetles (five Ips and one non-Ips) from Scolytinae subfamily using high-throughput sequencing and explored their putative role in symbiosis with the host insect. Results revealed the predominance of four fungal classes- Sordariomycetes, Saccharomycetes, Eurothiomycetes, and Dothidomycetes in all bark beetles. Apart from these, Agaricomycetes, Leothiomycetes, Incertae sedis Basidiomycota, Tremellomycetes, Lecanoromycetes, and Microbotryomycetes were also documented in different beetles. Five Ips bark beetles share a consortium of core fungal communities in their gut tissues consisting of 47 operational taxonomic units (OTUs) belonging to 19 fungal genera. The majority of these core fungal genera belong to the phylum Ascomycota. LEfSe analysis revealed a set of species-specific fungal biomarkers in bark beetles. The present study identified the gut mycobiont assemblage in bark beetles and their putative ecological relevance. An enriched understanding of bark beetle-fungal symbiosis is not only filling the existing knowledge gap in the field but may also unleash an unforeseen potential for future bark beetle management.

树皮甲虫（Bark beetles）是极具破坏性的森林害虫，鉴于其对森林退化的显著贡献，它们已成为林业生产中的重大隐患。其与真菌的共生关联，可帮助宿主克服在有毒且营养匮乏的基质——亦即针叶树组织——上生存所面临的多重挑战。真菌共生体可协助甲虫获取营养，并对树木产生的有毒次生代谢物进行解毒。尽管肠道是食物消化与解毒的核心场所，但目前关于树皮甲虫肠道真菌组（gut-mycobiome）的相关研究仍较为匮乏。本研究通过高通量测序技术，对小蠹亚科（Scolytinae）下的6种树皮甲虫（5种齿小蠹属（Ips）昆虫及1种非齿小蠹属昆虫）的肠道共生真菌进行了筛选，并探究了其与宿主昆虫的潜在共生功能。研究结果显示，所有供试树皮甲虫的肠道真菌群落中，粪壳菌纲（Sordariomycetes）、酵母菌纲（Saccharomycetes）、散囊菌纲（Eurothiomycetes）和座囊菌纲（Dothidomycetes）这4个真菌纲占据主导地位。除此之外，不同树皮甲虫的肠道中还分别检测到了伞菌纲（Agaricomycetes）、锤舌菌纲（Leotiomycetes）、地位未定担子菌门（Incertae sedis Basidiomycota）、银耳纲（Tremellomycetes）、茶渍菌纲（Lecanoromycetes）以及微球黑粉菌纲（Microbotryomycetes）。5种齿小蠹属（Ips）树皮甲虫的肠道组织中，共享一套由47个可操作分类单元（operational taxonomic units, OTUs）组成的核心真菌群落，这些群落隶属于19个真菌属。这些核心真菌属中的绝大多数均属于子囊菌门（Ascomycota）。LEfSe分析结果显示，不同树皮甲虫物种存在各自特有的真菌生物标志物。本研究明确了树皮甲虫肠道共生真菌的群落组成及其潜在的生态学意义。对树皮甲虫与真菌共生关系的深入认知，不仅填补了该领域当前的研究空白，同时也有望为未来树皮甲虫的综合治理发掘出尚未被认知的应用潜力。