铁皮石斛促生内生真菌的筛选与鉴定

Screening and Identification of Endophytic and Probiotic Fungi of Dendrobium catenatum

从铁皮石斛根中分离得到37株内生真菌,经过与组培苗共生筛选,获得9株促生菌,其中3株真菌对铁皮石斛的鲜质量增长率、根数增长率和芽数的促生效果最好。采用形态学观察和ITS序列测定相结合的方法对这9株促生菌进行鉴定。经形态学观察,初步鉴定出2株,均为瘤菌根菌属。根据rDNA ITS序列分析显示,2株与Epulorhiza sp.的相似性分别为100%和96%,1株与Guignardia camelliae的相似性达100%,1株与Mycosphaerella cruenta的相似性为99%。另外5株促生真菌分类地位尚不能确定,但这5株菌株与登录号为EU482263、GQ996178、AM901831、GU566294和GU566256的序列相似性分别达96%、95%、99%、98%和100%。

37 strains of endophytic fungi were isolated from roots of Dendrobium catenatum. Among which 9 strains were screened out to show the positive effect on the growth after being in vitro inoculated with D. catenatum seedlings ~ 3 strains were the most beneficial promote the growth rate of fresh biomass, the increment rate of the rad- ical number, and the number of new buds. The 9 probiotic fungi were identified by morphological characteristics observation and ITS gene sequence analysis. 2 strains were identified to belong to genus Epulorhiza according to the morphological characteristics. Based on ribosomal DNA （rDNA） sequence analysis, 2 strains were identified as Epulorhiza sp. （the identity was 100% and 96% respectively）, 1 strain was identified as Guignardia cameUiae （the identity was 100% ）, 1 strain was identified as MycosphaereUa cruenta （the identity was 99% ）. The classifi- cation position of the rest 5 growth-promoting fungi were not yet determined. However, the identity of the 5 strains with the GenBank codes EU482263, GQ996178, AM901831, GU566294 and GU566256 was 96%, 95%, 99%, 98% and 100%, respectively.