云南高黎贡山土壤可培养降解纤维素真菌的多样性

Phylogenetic diversiy of culturable cellulose-decomposing fungi in forest soil of Gaoligongshan Mountain,Yunnan

云南高黎贡山是中国生物多样性保护具有全球意义的关键区域,研究该地区土壤中降解纤维素真菌（cellulose-decomposing fungi,CDF）多样性及分布状况对筛选高效CDF和相关功能基因研究具有重要意义。利用羧甲基纤维素（CMC）刚果红平板和PDA平板,分离培养了高黎贡山海拔960～2900m之间0～20cm深度的土壤样品的好氧CDF,通过液体发酵鉴定其纤维素酶活力,并对其rDNA内转录间隔区（ITS）序列进行分析,用Neighbor-Joining法构建系统进化树。结果发现中低海拔地区土壤CDF数量高于高海拔地区,且数量与样地海拔、土壤含水量、温度、有机质和全氮含量呈显著相关（P〈0.05）;CDF在样地内多样性与土壤有机质、全氮、含水量显著相关（P〈0.05）;植被类型和人为干扰对CDF的数量和分布都有一定影响。在10个样地中共筛选到35株具有较高降解纤维素类物质能力的真菌,其96h液体发酵测量CMC酶活力范围在79.6（菌株6）～228.9IU（菌株3）。这些株菌分属15个属,其中曲霉属（Aspergillus）、青霉属（Penicillium）、葡萄状穗霉属（Stachybotrys）、毛壳霉属（Chaetomium）的真菌共计20株,占总分离菌株数的57.1%,是高黎贡山土壤中CDF的优势菌群。

In order to understand the diversity of culturable cellulose-decomposing fungi（CCDF）,ten surface（0-20cm）soil samples collected at the altitude ranging from 960m to 2900m,in Gaoligongshan Mountain,where are the key areas for biodiversity protection in the world,were studied.Cellulose-decomposing aerobic fungal isolates were obtained using both Carboxymthyl cellulose-congo red（CMC-CR）plates and potato dextrose agar（PDA）plates from the soils.Polysaccharide hydrolase（Endoglucanase）activities of the isolates were determined by liquid fermentation.The plate counting results showed that the numbers of the cellulose-decomposing fungi（1.1×103-1.4×104 CFU/g）from lower altitude soils were higher than those from higher altitude soils.The correlation analysis showed that the correlation is varied among culturable cellulose-decomposing fungi and the ecological factors.The quantity and diversity of culturable cellulose-decomposing fungi in these soils are significantly correlated with organic matter,total nitrogen and water content.In addition,the quantity of them are significantly correlated with temperature and altitude.Different plant community and human disturbance have effected on the quantities and diversity of CCDF.A total of thirty five independent isolates belonging to 15 fungal genera were identified by both morphological characteristics and rDNA ITS sequencing analyses.Aspergillus,Penicillium,Stachybotrys,and Chaetomium were the four dominant genera,to which the isolates belong.These results will be important to the further studies of diversity,genetics of cellulose-decomposing fungi in Gaoligongshan Mountain areas.