Analysis of the community structure of arbuscular mycorrhizal fungi colonizing crop root by PCR-DGGE.

丛枝菌根(AM)真菌与植物根系之间的共生关系在自然界中广泛存在。已经研究了接种AM真菌对农业种植系统的积极影响，包括提高对磷和其他养分的吸收，提高抗逆性，以及有益的植物生长调节。利用聚合酶链式反应进行DNA扩增是一种检测和鉴定AM真菌的技术。本研究探讨了聚合酶链式反应-变性梯度凝胶电泳法在AM真菌群落结构研究中的应用。从每个孢子中分离到5种AM真菌DNA(Glomus etunicatum、Glomus Mosseae、Gigaspora margarita、Gigaspora roSea、Acaulospora long ura)，而镰刀菌DNA。和高山被孢霉(Mortieralla Alpina)。将孢子粉碎，用冻融法提取其DNA。以该粗提物为模板进行聚合酶链式反应。采用套式聚合酶链式反应的方法，从真菌分离株中扩增出一段长达500个碱基的18SrDNA片段。对真菌分离株的PCR产物进行DGGE分析，以检测不同真菌分类群之间的差异。18SrDNA片段的DGGE可以解决大多数真菌的物种差异，但不能区分G.etunicum和Gi。玛格丽塔鸡尾酒。我们认为，PCR-DGGE分析是研究AM真菌群落结构的一个很好的方法。

The symbiotic association between arbuscular mycorrhizal (AM) fungi and plant roots is widespread in nature. The positive effects of AM fungus inoculation on agricultural cropping systems have been investigated and include improved uptake of phosphorus and other nutrients, increased stress tolerance, and beneficial plant growth regulation. DNA amplification by PCR has been proposed as a technique for AM fungus detection and identification. I have examined the application of PCR-DGGE (Denaturing Gradient Gel Electrophoresis) analysis to the study of AM fungal community structure colonizing plant root in this research. Five kinds of AM fungal DNA (Glomus etunicatum, Glomus mosseae, Gigaspora margarita, Gigaspora rosea, Acaulospora longura) were isolated from each spore, while DNA of Fusarium sp. and Mortieralla alpina were isolated from each mycelia. Spore was crushed and its DNA was extracted by use of the freeze-thaw method. This crude extract was used as template for PCR. A nested PCR strategy was employed to amplify a 500-bp region of the 18SrDNA from fungal isolates. PCR products from fungal isolates were subjected to DGGE analysis to examine the variation seen between different fungal taxa. DGGE of the 18SrDNA fragments could resolve species differences from most of fungi used, but was unable to discriminate between G. etunicatum and Gi. margarita. We suggest that PCR- DGGE analysis is a good approach for investigating AM fungal community structure.