Department of Environmental Science, Policy and Management, 151 Hilgard Hall, University of California, Berkeley, California 94720-3110.
Mycologia. 2004 Jul-Aug;96(4):730-41. doi: 10.1080/15572536.2005.11832921.
Matsutake are commercially important ectomycorrhizal basidiomycetes in the genus Tricholoma. Despite their importance, the systematics of this species complex have remained elusive and little is known about their origin and biogeography. Using DNA analyses on a worldwide sample of matsutake, we present here the first comprehensive definition of natural groupings in this species complex. We infer patterns of migration and propose Eocene origins for the group in western North America by a transfer from an angiosperm-associated ancestor to an increasingly specialized conifer symbiont. From these origins, matsutake appear to have followed migratory routes parallel to those of coniferous hosts. Patterns of vicariance between eastern North America and eastern Asia are resolved and their origins are suggested to stem from migration through Beringia. Using an analysis of genetic dissimilarity and geographical distance, we reject both the possibility that migration into Europe and Asia occurred through Atlantic bridges and the connection between matsutake populations in the Mahgrebi Mountains and those from Europe. Instead, African and European matsutake appear to be the most recent ends of a westward expansion of the domain of these fungi from North America.
松茸是松口蘑属中具有商业重要性的外生菌根担子菌。尽管它们很重要，但这个物种复合体的系统发育仍然难以捉摸，人们对它们的起源和生物地理学知之甚少。利用对来自世界各地的松茸样本的 DNA 分析，我们在此首次全面定义了这个物种复合体中的自然分组。我们推断了迁徙模式，并提出该物种组起源于始新世的北美西部，从与被子植物相关的祖先转移到与针叶树共生的越来越专门化的共生体。从这些起源来看，松茸似乎沿着与针叶树宿主平行的迁徙路线出现。解决了东亚和北美东部之间的隔离模式及其起源问题，认为它们是通过白令海峡迁徙而来的。通过对遗传差异和地理距离的分析，我们否定了松茸通过大西洋桥进入欧洲和亚洲的可能性，也否定了马格里布山脉与欧洲的松茸种群之间存在联系的可能性。相反，非洲和欧洲的松茸似乎是这些真菌从北美向西扩张的最新终点。
