Unprecedented bacterial diversity within the bacteriome of fungi

Knowledge of associations between fungal hosts and their bacterial associates has steadily grown in recent years as the number and diversity of examinations have increased, but current knowledge is predominantly limited to a relatively small number and diversity of fungal taxa and bacterial partners. Here, we screened for potential bacterial associates in over 700 phylogenetically diverse fungal isolates, representing 367 genera, or a tenfold increase compared with previously examined fungal genera, including isolates from several previously unexplored phyla. Both a 16S-based exploration of fungal isolates from four distinct culture collections spanning three continents, and a bioinformatic screen for bacterial-specific sequences within fungal genome sequencing projects, revealed that a surprisingly diverse array of bacterial associates are frequently found in otherwise axenic fungal cultures. We demonstrate that bacterial associations with diverse fungal hosts appear to be the rule, rather than the exception, and deserve more consideration in microbiome studies and in examinations of microbial interactions.

近年来，随着相关检测的数量与多样性不断提升，学界对真菌宿主与其细菌共生体之间关联的认知持续深化，但当前的认知仍主要局限于数量和多样性相对有限的真菌类群与细菌共生伙伴。本研究针对700余株系统发育多样的真菌分离株开展潜在细菌共生体筛选，这些分离株涵盖367个真菌属，相较于此前已研究的真菌属数量提升了十倍，同时还包含数个此前未被探索的真菌门来源的分离株。研究团队一方面对覆盖三大洲的四个独立菌种保藏中心的真菌分离株开展了基于16S rRNA（16S ribosomal RNA）的分析，另一方面通过对真菌基因组测序项目中的细菌特异性序列进行生物信息学筛选，两项分析均发现：在原本无菌的真菌培养物中，常存在种类出乎意料多样的细菌共生体。本研究证实，细菌与多样真菌宿主的关联实为普遍规律而非特例，这在微生物组研究以及微生物互作分析中值得更多关注。