Species clarification of oyster mushrooms in China

Authors: Jing Li Xing He XiaoBin Liu Zhu L Yang ZhiWei Zhao

Publish Date: 2017/01/18

Volume: 16, Issue: 3, Pages: 191-203

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Abstract

Species of the Pleurotus ostreatus complex oyster mushrooms are one of the main groups of cultivated edible mushrooms in China with abundant strains and a complex genetic background Although the cultivation of oyster mushrooms is a very important industry in China the inconsistent nomenclature of the complex is controversial and has led to much confusion and economic loss in the mushroom industry In this study we performed molecular identification of the species complex based on sequences of the internal transcribed spacer region ITS translation elongation factor 1α TEF1 and two genes that encode subunits of RNA polymerase II RPB1 and RPB2 A total of 284 samples with different commercial names gathered from different mushroom spawn preservation centers companies and field isolations were investigated via phylogenetic analyses inferred from a single locus or multiloci Our analyses indicated that 56 of the strains were labeled with improper scientific names and that all of the strains could be divided into seven lineages representing one morphological species each namely P abieticola P eryngii P cf floridanus P ostreatus P placentodes P pulmonarius and P tuoliensis Reference sequences for accurate identification of the taxa were developed or suggested Meanwhile we evaluated the suitability of the four candidate segments as DNA barcodes Our analyses indicated that RPB2 was the most promising candidate segment of DNA barcode for the P ostreatus species complex taking into consideration the polymorphisms and other aspects of the four markersThe authors are very grateful to Prof Dr YC Zhao Yunnan Academy of Agricultural Sciences Mr F Nie Anhui Academy of Agricultural Sciences Ms J Yang Fujian Academy of Agricultural Sciences Dr P Zhang Hunan Normal University Prof JW Shen Henan Agricultural University and Dr XD Yu Shenyang Agricultural University for providing strains and specimens for this study The anonymous reviewers are acknowledged for their constructive comments and suggestions This study is supported by the National Basic Research Program of China 973 Program No 2014CB138305 and the Largescale Scientific Facilities of the Chinese Academy of Sciences 2009LSFGBOWS01Phylogenetic tree inferred from ML analysis with branch support obtained by ML and BI analyses based on a fourlocus ITS TEF1 RPB1 and RPB2 dataset Branch support values are indicated by numbers above branches MLBP/BIPP Taxon labels indicate strain number listed in Suppl Table 1 Location of P ostreatus P382 P383 CCMSSC 00323 and P cf floridanus P289 P290 are highlighted in blue and red respectively GIF 361 kbPhylogenetic tree inferred from ML analysis with branch support obtained by ML and BI analyses based on ITS TEF1 RPB1 and RPB2 Branch support values are indicated by numbers above branches MLBP/BIPP Taxon labels indicate strain number listed in Suppl Table 1 Strains of P ostreatus and P cf floridanus in single gene phylogeny ITS TEF1 and RPB1 are highlighted in purple and red respectively GIF 1184 kbPhylogenetic tree inferred from ML analysis with branch support obtained by ML and BI analyses based on RPB2 Branch support values are indicated by numbers above branches MLBP/BIPP The strain names labeled on our collections correspond to Suppl Fig 2 GIF 445 kbPhylogenetic tree inferred from ML analysis with branch support obtained by ML and BI analyses based on TEF1a and RPB1b Branch support values are indicated by numbers above branches MLBP/BIPP The samples of P ostreatus and P cf floridanus were highlighted in different colors GIF 130 kbPhylogenetic tree inferred from ML analysis with branch support obtained by ML and BI analyses based on TEF1a and RPB1b Branch support values are indicated by numbers above branches MLBP/BIPP The samples of P ostreatus and P cf floridanus were highlighted in different colors GIF 130 kbPhylogenetic relationships among reference collections and other samples of Pleurotus inferred from ITS sequences using ML analysis Branch support values are indicated by numbers above branches MLBP ≥ 70 Accession numbers for sequences retrieved from GenBank database are listed in Suppl Table 1 Specimens in P ostreatus species complex from China are highlighted in blue Reference collections in singlelocus and multilocus phylogenetic analyses are labeled with a black rectangle JPEG 103 MB

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