Study On The Symbiotic Honey Fungus Group Of The Medicinal Fungus Rhizoctonia Solani

Polyporus umbellatus(Pers.)Fr.,belonging to Polyporaceae,is a widespread medicinal fungus which mainly distributed in China,Japan and other temperate regions of the Northern Hemisphere.The dried sclerotia of P.umbellatus has been used as herb medicine more than 2000 years in China to cure edema and promote diuretic processes.At present,the medicinal materials are mainly depending on wild collecting.Both increasing commercial demands and less effective protection led to excessive harvest and a dramatic decline of wild resources in China.Some Armillaria species have been known as symbionts of P.umbellatus.It has been certified that growth of P.umbellatus sclerotia mainly depend on Armillaria spp.to supply their needing nutrition.But in fact,there have been problems with both the quality of the sclerotia and production efficiency for cause of ambiguous Arimillaria species used,such as uncertain species and unknown ecological characteristics.It is an urgent problem to understand the seed characteristics of Armillaria symbionts of P.umbellatus.In this research,we collected sclerotial samples of P.umbellatus,isolated Armillaria strains from sclerotial samples,identified these strains,investigated the interaction between P.umbellatus and Armillaria,studied its culture characteristics.At the same time,the correlation between P.umbellatus and Armillaria was analyzed.The main contents are as follows:1.We collected sclerotial samples from 11 provinces in China,47 Armillaria strains were isolated and their sequences of ITS,β-tubulin and elongation factor-1 alpha gene were obtained,compared with Armillaria in China,all of the Armillaria isolates could be classified into 5 phylogenetic lineages in China except one singleton:lineage 6.lineage 4、lineage 8、lineage 1 and A.cepistipes,one lineage(lineage 8)was recognized by delimitation of an uncertain phylogenetic lineage in previous study.2.Result of simple Mantel test implied that phylogenetic related P.umbellatus tend to interact with phylogenetic related Armillaria species.Phylogenetic network analyses revealed that the interaction between P.umbellatus and Armillaria is significantly influenced by the phylogenetic relationships of the Armillaria.3.In order to clarify whether the Armillaria was related to the main components of P.umbellatus,the contents of polysaccharides and ergosterol in P.umbellatus were determined.The results showed that the contents of polysaccharides and ergosterol were obvious difference in different regions.The contents of total nitrogen,total phosphorus,total potassium and organic matter in the soil of P.umbellatus were also determined,combining the branchlength of P.umbellatus and the pholotype of Armillaria,which were analyzed by redundancy.The content of polysaccharide in P.umbellatus has certain correlation with soil total nitrogen,total phosphorus and soil organic matter content.The content of ergosterol in Polygonum capitatum has certain correlation with soil total nitrogen,total phosphorus,branchlength of P.umbellatus and soil organic matter.There was no correlation between the pholotype of Armillaria and the main components of P.umbellatus.4.Compared with Armillaria sequences associated with Gastrodia elata reported in literature,phylogenetic analyses indicated that 10 clades of Armillaria could be classified in total and six and seven of them are associates with P.umbellatus and G.elata respectively.Three clades are shared by P.umbellatus and G.elata,which mainly include the strains from Shaanxi,Shanxi,Jilin,Heilongjiang,Guizhou,Gansu and Sichuan.The strains from Yunnan and Tibet are of highly specificity.Our results elucidate the differences and similarities of Armillaria partners between P.umbellatus and cultivated G.elata through phylogenetic aspect,and provide important theoretical support for the selection of Armillaria species in cultivation of P.umbellatus and G.elata.5.All the Armillaria strains were divided into 8 different morphotypes according to the main phenotypic traits(A-H).Morphotype F contains the largest number of strains,followed by morphotype B and E.Combining molecular identification and morphological characteristics,twelve strains were selected for liquid fermentation.The results showed that M8-3 and M4 have highest biomass on the third day of fermentation,M3 has highest polysaccharide content on the twenty-one day,M3 has highest carboxymethyl cellulose enzyme activity on the twelve day,M20 has highest xylanase activity on the twenty-four day,M6-2 has highest xylanase activity on the twenty-four day and M8-3 on the eighteen day.In this research,Armillaria strains obtained from different areas can be applied to the original ecological cultivation of P.umbellatus,and the basic data of the experiment can provide a theoretical reference for the selection of Armillaria strains during the cultivation of P.umbellatus.