Submitted to: Fungal Genetics and Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/23/2012
Publication Date: 6/1/2012
Publication URL: http://handle.nal.usda.gov/10113/57550
Citation: Du, X., Zhao, Q., O'Donnell, K., Rooney, A.P., Yang, Z.L. 2012. Multigene molecular phylogenetics reveals true morels (Morchella) are especially species-rich in China. Fungal Genetics and Biology. 49(6):455-469. Interpretive Summary: Because export of dried true morels (Morchella) from China and other morel-rich countries including the United States has rapidly grown to become a multimillion dollar cottage industry, the present conservation genetic study in China was conducted to provide detailed knowledge of their geographic distribution and genetic diversity needed to formulate informed policies directed at insuring commercial harvests are sustainable. Toward this end, 361 collections of true morels were made in 21 Chinese provinces during the 2003-2011 growing seasons to assess the genetic diversity of this economically important group of mushrooms. All of the collections were genetically typed using DNA sequence data. The DNA typing results revealed that 30 species of true morels were present in China, compared with 22 in Europe and 19 within the United States. These analyses also indicated that 11 of the species discovered in China were new to science, including nine species of yellow morels and two species of black morels. The results of this study will benefit conservation biologists and policymakers charged with developing science-based agri-environmental policies designed to insure that annual commercial harvests of morels improve, and that they are sustainable and ecologically sound. In addition, knowledge of their genetic diversity should benefit biotechnologists interested in cultivating morels commercially.
Technical Abstract: The phylogenetic diversity of true morels (Morchella) in China was estimated by initially analyzing nuclear ribosomal internal transcribed spacer (ITS) rDNA sequences from 361 specimens collected in 21 provinces during the 2003-2011 growing seasons, together with six collections obtained on loan from three Chinese herbaria. Based on the results of this preliminary screen, 40 Esculenta Clade (yellow morels) and 30 Elata Clade (black morels) were chosen to represent the full range of phylogenetic diversity sampled. To investigate their species limits, we generated DNA sequences from portions of three protein-coding genes (RPB1, RPB2 and EF-1a) and domains D1 and D2 of the nuclear large subunit (LSU) rDNA for all 70 collections. To fully assess evolutionary relationships, previously published multilocus DNA sequence data representing all known Morchella species was included in this study. Phylogenetic analyses employing maximum parsimony and maximum likelihood frameworks resolved 30 species in China compared with 22 in Europe and 19 within North America. Eleven novel phylogenetically distinct species were discovered in China, including two species within the Elata Clade and nine within the Esculenta Clade. Of the 30 species in China, 20 appear to be endemic, nine were also represented in Europe, and four putatively fire-adapted species have disjunct distributions in China, Europe, and western North America. Although the diversification time estimates place the Esculenta Clade in China as early as the late Cretaceous and the Elata Clade by the early Oligocene, 27 of the 30 Chinese species radiated between the middle Miocene 12.15 Mya and present