A heritable symbiont and host-associated factors shape fungal endophyte communities across spatial scales

1. Although microbial ecologists are intensely interested in the processes governing microbial community assembly, progress has been limited by a lack of studies that span multiple geographical scales and levels of biological organization. 2. We used high throughput sequencing to characterize foliar fungal endophyte communities and host plant genetic structure both within, and among, 24 populations of spotted locoweed (Astragalus lentiginosus) across the Great Basin Desert. 3. Across the Great Basin, both within, and among populations of the host plant, fungal endophyte richness was predicted by plant size and variation in the seed-borne, heritable fungus, Alternaria fulva, which produces the bioactive alkaloid swainsonine. 4. The degree of between-plant turnover in the endophyte community was inversely related to host plant inbreeding and average plant size, and positively related to the relative abundance of A. fulva. Plant size was inversely related to endophyte community richness, b...1. 尽管微生物生态学家对调控微生物群落构建的核心过程抱有浓厚研究兴趣，但当前相关研究进展却因缺乏覆盖多地理尺度与多层生物组织层次的工作而受到显著限制。2. 本研究采用高通量测序（high throughput sequencing）技术，对分布于大盆地沙漠（Great Basin Desert）的24个斑状疯草（Astragalus lentiginosus）种群的内部及种群间的叶部真菌内生菌（foliar fungal endophyte）群落与宿主植物遗传结构开展了表征分析。3. 在整个大盆地沙漠区域内，无论是宿主种群内部还是种群间，真菌内生菌的丰富度均能通过植株体型大小，以及可通过种子传播的遗传真菌——产生物活性生物碱苦马豆素（swainsonine）的褐黄链格孢（Alternaria fulva）的变异情况进行预测。4. 内生菌群落的植株间周转程度与宿主植物近交水平及平均植株体型呈负相关，而与褐黄链格孢（A. fulva）的相对丰度呈正相关。植株体型与内生菌群落丰富度呈负相关，b...