铁皮石斛内生真菌的分离鉴定及其促宿主生长作用

利用微生物学传统分离培养方法从野生铁皮石斛根部分离内生真菌,依据形态学和真菌18SrDNA ITS序列分析对菌株进行分类,并采用正交设计法优化菌丝体液体培养基,考察发酵液对铁皮石斛组培苗生长的影响,以期为人工种植铁皮石斛提供优良菌肥。结果显示,共分离到4株内生真菌,其中TPSH1、TPSH2、TPSH3为镰刀菌属(Fusarium),TPSH4为柱霉属(Scytalidi-um)。优化后确定培养液的组分为:麦麸25g/L,土豆20g/L,蔗糖10g/L,1/2MS。菌株发酵液分别喷施铁皮石斛组培苗8周后,与对照(1/2MS)相比,以TPSH4菌株液体发酵8d,对铁皮石斛生长促进作用明显,成活率提高30.43%,植株高度增加了31.21%,鲜质量增加40.61%。TPSH4为具有促宿主生长作用的新菌株,其发酵液可作为菌肥,用以促进人工栽培铁皮石斛的生长。

Isolation and Identification of Endophytic Fungi from Dendrobium officinale and Study of Their Impacts on Host Growth

Endophytic fungi were isolated from the roots of wild Dendrobium officinale by using conventional microbiological methods,and their taxonomic statuses were determined based on morphological characteristics coupled with 18S rDNA ITS sequence analysis.The results showed that four endophytic fungi were isolated from the root of D.officinale,with TPSH1,TPSH2 and TPSH3 belonging to the genus of Fusarium,and TPSH4 belonging to Scytalidium.And then the liquid culture medium was optimized by orthogonal test,and the impacts of their fermentation liquor on the growth of tissue culturing seedlings were observed.After optimization,the culture solution consisted of 25 g/L bran,20 g/L potato,10 g/L sucrose and 1/2 MS.Compared with the contrast(1/2 MS),the TPSH4 8-day fermentation liquor had observable promotion for the growth of D.officinale sprayed after 8 weeks.The survival ratio was improved by 30.43%,and the plant height and fresh weight increased by 31.21% and 40.61%,respectively.TPSH4 is a new fungus with growth-promoting effect on its host,and its fermentation liquor can be used as fertilizer to promote the growth of artificially cultivated D.officinale.