| Tremella fuciformis Berk, also known as white edible fungus, snow edible fungus is a combination of precious medicine and edible fungi. Traditional Chinese Medicine theory holds that Tremella fuciformis is mild-natured, sweet, non-toxic, with the effect of tonifying kidney, moistening lung, generating secretion of saliva and relieving cough. The modern medical science research confirms that Tremella fuciformis can improve body immunity, protect liver to counteract poison, fight cancer and postpone senility. Along with the improvement of people’s living standard and the enhancement of health care consciousness, the potential for consumption of Tremella fuciformis is huge.Different from most of edible fungus, Tremella fuciformis complete its life cycle accompanied by the cohabitant fungus-xianghui. Previous research have shown that Tremella fuciformis had a weak ability to decompose the cellulose and lignin in the wood. In the process of mushroom cultivation, xianghui decompose wood into nutriment, which is essential for the growth of Tremella fuciformis. Therefore, the vitality of xianghui is directly related to the yield of Tremella fuciformis. However, the cognition of xianghui is very deficient currently. Especially, the taxonomical status exists much controversy, and the biological characteristics of xianghui is rarely reported, which bring much obstacles not only for defining the interaction mechanism of Tremella fuciformis and xianghui but also for breeding the new strains of Tremella fuciformis.In this paper, the phylogeny of5strains of xianghui,which were collected from different places and paired with cultivated Tremella fuciformis, was determined by β-tubulin sequences analysis. Furthermore, the biological characteristics of these strains was analyzed by carbon source, nitrogen source, temperature and pH test. These results will establish foundation for the interaction mechanism and breeding the new strains of Tremella fuciformis and xianghui. And the findings are as follows:1. The phylogeny of5strains of xianghui,which were collected from different places and paired with cultivated Tremella fuciformis, was determined by β-tubulin sequences analysis. The β-tubulin sequences of the5strains were analyzed by Clustal W sequence alignment with MEGA4.0software. The results showed that the β-tubulin sequences of5tested xianghui shared high homology. It suggested that5tested xianghui were the same species at β-tubulin level. Using the BLAST of Genbank, the5tested strains of xianghui were identified as Annulohypoxylon stygium. 2. There were9kinds of carbon sources to analyse the ability of utilizing carbon source of5tested xianghui. The results showed that monosaccharide(such as fructose, glucose, mannitol), disaccharide(such as sucrose, lactin) and CMC all could be used by xianghui. And the optimal carbon source was fructose. Xylose, sucrose, glucose and sorbitol took the second place. The utilization of lactin was the worst of all.3. In order to know the ability of utilizing nitrogen source,11kinds of nitrogen sources were used. The results showed that5tested strains of xianghui could use the nitrogen source extensively. Ammonium nitrogen(such as NH4C1,(NH4)2SO4,(NH4)3PO4), nitrate nitrogen(such as NaNO3) and organic nitrogen(such as glycine, Cys) all could be used. And the optimal nitrogen source was NH4Cl and (NH4)2SO4. Cys and NH4NO3took the second place.(NH4)3PO4was the worst.4. Temperature test showed that5strains of xianghui could grow from10～40℃on PDA medium. There was no growth when the temperature was lower than10℃or higher than40℃. The optimum temperature was30℃.5. The results of testing the adaptability for pH showed that for the mycelial growth of5tested strains, the range of pH values was4.01～10.20, and the favorable pH was5.00～9.03. The growth fell sharply when the pH was more than9.03. It also showed that the optimum pH was neutral partial acid. |
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