The Application In Molecular Taxonomy Of Genus Pleurotus Based On RDNA ITS Sequences

The genus Pleurotus is widespread wood saprobiotic fungus with edible and medical function, and its taxonomy is confusion. In this study, The sequences of rDNA ITS (including 5.8S rDNA) region of 7 species, 11 cultivated strains in China of Pleurotus and Auricularia auricular(outgroup) were analyzed by PCR amplified and cloned DNA sequencing. The other 23 species ITS sequences of Pleurotus and Hohenbuehelia grisea (as outgroup) were assempled from Genbank. Based on those ITS sequences, the phylogenetic tree of Genus Pleurotus and relationship tree of cultivated species in China were constructed, the mean distance of species and strains of Pleurotus is also showed their relationships. The results are as follows:1. The ITS regions ranged in length from 627-667bp, with ITS1 225-266bp and ITS2 228-262bp. Of the 731bp aligned positions, there were 317 variable sites(176 in ITS-1, 139 in ITS-2 and 4 in 5.8S), and 247 informative sites(142 in ITS-1, 103 in ITS-2 and 2 in 5.8S).2. The phylogentic tree, Hohenbuehelia grisea as outgroop, generated from maximum parsimony analysis and the mean distance showed that Genus Pleurotus were divided into six branches, One including P. abieticola, P. fossulatus, P. fossulatus, P. eryngii, P. nebrodensis, P. populinus, P. subarelatus, P. albitus, P. ferulae, P. spodoleucus, P. columbinus, P. sajor-caju, P. floridanus and P. ostreatus ; the second including P. australis, P. sapidus, P. pulmonarius and P. oputiae; the third including P. djamor, P. incarnates, P. flabellatus, P. calyptratus; the fourth including P. euosmus, P. cornucopiaeand P. citrinopileatus; the fifth including P. cystidiosus, P. fusscosquamulosus, P. smithii and P. dryngii, and the last including P. javanicus and P. tuberregium. The result also showed that they were the same species between P. ostreatus and P. floridanus, P. cornucopiae and P. citrinopileatus, P. djamor and P. incarnatus, P. spodoleucus and P. columbinus, and there were close relationship between P. ferulae, P. nebrodensis and P. eryngii. Moreover the result showed that it was different specie between P. sajor-caju and P. pulmonarius.3. The phylogentic tree, Auricularia auricula as outgroop generated from maximum parsimony analysis and the mean distances showed that those main cultivated strains in china were divided into five branches, the first including P. columbinus, P. sajor-caju, P. floridanus, P. ostreatusm, P. sp.(yuan ci ce er), P. sp.(ping 802), P. sp.(ji-gu), P. sp. (xiu zhen gu); the second including P. eryngii, P. nebrodensis, P. ferulae, P. sp. (xing bao gu) and P. sp. (xiang ce er); the third includeing P. populinus and P. sp. (ping 963-1); the fourth including P. pulmonariu, P. sapidus, P. sp. (ping ce 5), P. sp. (ping8804), P. sp. (xiao bai ping gu); and the last including P. cornucopiae, P. citrinopileatus and P. sp. (ji zhi jun). The result also showed that P. sp. (yuan chi ce er), P. sp. (Ji-gu), P. sp. (xiu zhen gu) all belong to the same specie of P. columbinus, and ping ce 5, xiao bai ping gu are belong to P. sapidus. Moreover the result showed that they were very close relationships between P. cornucopiae, P. citrinopileatus and ji zhi jun, and they may be the same specie as well.The above results are of significance on solving disorded phenomenon of Pleurotus taxon and further utilizing rare species of Pleurotus.