Department of Ecology, Evolution, and Marine Biology, University of California-Santa Barbara, Santa Barbara, California, 93106, USA.
Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico.
Am J Bot. 2022 Jan;109(1):83-98. doi: 10.1002/ajb2.1792. Epub 2022 Jan 18.
Foliar fungal endophytes vary in their distributions across landscapes or plant host taxa, indicative of specialized ecologies and host specific adaptations. Accounts of specialization, however, depend on the taxonomic breadth and geographic range of the host plants included in each study. A broad region-scale study or deep sampling of diverse potential host species still remains relatively rare but is becoming increasingly possible with high-throughput sequencing.
Amplicon sequencing was used to rapidly identify the fungal endophytic community among six pine (Pinus, Pinaceae) species co-occurring across northeastern United States and to test for site and host specialization. We focused on the endophytic genus Lophodermium (Rhytismataceae), whose species members are thought to specialize on different pine species, to test if amplicon sequencing could rapidly verify previously implied or discover new patterns of host specificity.
While amplicon sequencing could analyze more samples at greater depths and recover greater numbers of unique Lophodermium taxa than when endophyte communities were surveyed with traditional culturing methods, patterns of specialization were not better supported. This may be because amplicon sequencing can indiscriminately capture non-host specific organisms found incidentally from plant tissues or because we have overestimated host-specificity in the past with biased culturing techniques.
Amplicon sequencing can quickly identify patterns of host specificity by allowing large-scale surveys but has limitations in quantifying the level of intimacy of these relationships.
叶内真菌内生菌在景观或植物宿主分类群中的分布存在差异，这表明它们具有专门的生态和宿主特异性适应。然而，关于专业化的描述取决于每个研究中包含的宿主植物的分类广度和地理范围。广泛的区域尺度研究或对不同潜在宿主物种的深度采样仍然相对较少，但随着高通量测序的出现，这种情况变得越来越普遍。
使用扩增子测序技术快速鉴定美国东北部六种松属（松科）植物中共生的真菌内生群落，并测试其是否具有特定的生境和宿主。我们专注于内生属 Lophodermium（Rhytismataceae），其物种成员被认为专门针对不同的松树物种，以测试扩增子测序是否能够快速验证先前暗示或发现新的宿主特异性模式。
虽然扩增子测序可以比传统的培养方法更深入地分析更多的样本，并且可以恢复更多独特的 Lophodermium 分类群，但专业化模式并没有得到更好的支持。这可能是因为扩增子测序可以不加区分地从植物组织中偶然捕获非宿主特异性生物，或者因为我们过去使用有偏差的培养技术高估了宿主特异性。
扩增子测序可以通过允许大规模调查来快速识别宿主特异性模式，但在量化这些关系的亲密程度方面存在局限性。
