Two new species in the Suillus spraguei complex from China

ABSTRACT

Suillus spraguei, synonym S. pictus, has been reported from eastern North America and eastern Asia associated with Pinus subgenus Strobus. Published phylogenetic analyses of rRNA internal transcribed spacer (ITS) sequence and population genetic studies indicated that S. spraguei as currently circumscribed might contain several geographically distinct species. This study examined this possibility through a multigene analysis of S. spraguei specimens from eastern North America and eastern Asia. These specimens were associated with Pinus strobus, P. koraiensis, P. armandii, and P. kwangtungensis. The multigene analysis included three genomic regions: the genes for translation elongation factor 1α (TEF1) and RNA polymerase II largest subunit (RPB1), and the nuc rRNA segments ITS1-5.8S-ITS2 (ITS) and 28S D1–D2 domains (28S). This study confirms that the S. spraguei complex consists of at least three cryptic species: S. spraguei sensu stricto associated with P. strobus in eastern North America; S. phylopictus associated with multiple species in Pinus subgenus Strobus (5-needle pines) throughout China and Japan; and S. kwangtungensis, currently found only in P. kwangtungensis forests in southeastern China. A third new species from Japan and Korea was suggested based on ITS phylogeny. Morphologically, S. spraguei and S. phylopictus resemble each other, whereas S. kwangtungensis is covered with more floccose scales. The new species add to the knowledge of macrofungal diversity in eastern Asia and highlight the necessity of comparing broadly distributed species complexes using morphological, molecular, and ecological data.

KEYWORDS:

• Biogeography
• host specificity
• Suillus kwangtungensis
• Suillus phylopictus

ACKNOWLEDGMENTS

The authors thank the National Natural Science Foundation of China for financial support to Pei-gui Liu (Y21A311211). Field exploration and molecular work in America was supported by the Chicago Botanic Garden and the joint Chicago Botanic Garden/Northwestern University Program in Plant Biology and Conservation graduate training program. We thank Xiang-hua Wang, Wenqing Zhao, Xiaojin Wang, and Bo Li for their assistance in the field. Zhu-liang Yang’s research group at Kunming Institute of Botany and Chinese Academy of Sciences are thanked for arranging and participating in some of the field trips. The following herbaria and personal collector are acknowledged for loaning specimens and permitting destructive sampling for DNA extraction: University of Tennessee Herbarium, Cryptogamic Herbarium, Kunming Institute of Botany, Field Museum of Natural History, University of California, Berkeley, T.D. Bruns, and Bradley R. Kropp. DNA sequences were generated in the Pritzker Laboratory for Molecular Systematics and Evolution at the Field Museum. Patrick Heredeen is thanked for the use of his microscope and Andrew Wilson for training and help with molecular data analyses. Mycologia reviewers are thanked for critical comments on the manuscript.

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