先锋牧草-香根草联合固氮菌多样性

Diversity of associated nitrogen-fixing bacteria isolated from the pioneer plants-Vetiver zizanioides

【目的】香根草(Vetiver zizanioides)是一种多年生禾本科草本植物,具有极强的生态适应性和抗逆能力,可作饲料和水土保持用。通过研究香根草联合固氮菌多样性,为进一步研究和应用打下基础。【方法】采用无氮培养基,首次从香根草中分离到47株联合固氮菌,分别应用SDS-PAGE全细胞蛋白质电泳、DNA指纹图谱、唯一碳源和16SrDNA全序列测定等方法,进行聚类和多样性分析。【结果】SDS-PAGE、IS-PCR和Bio-BIQA碳源利用的聚类结果基本一致,将供试菌株分为6个类群和4个单菌株;16SrDNA序列测定表明,从香根草中分离的菌株包括了佛莱辛草螺菌(Herbaspirillum frisingense)、中型假食酸菌(Pseudacidovorax intermedius)、恶臭假单胞菌(Pseudomonas putida)、荧光假单胞菌(Pseudomonas fluorescens)、越南伯克氏菌(Burkholderia vietnamiensis)、阴沟肠杆菌(Enterobacter cloacae)、路德维希肠杆菌(Enterobacter ludwigii)和松江壳聚糖降解菌(Mitsuaria chitosanitabida)等不同菌种。【结论】香根草联合固氮菌具有较大的资源多样性,对固氮菌资源的扩展和将来牧草上的应用具有重要意义。

[ Objective] Vetiver zizanioides is a perennial grass of the Poaceae family, known of its silage, soil and water conservation role. The aim of the study was to collect and identify the resources of the nitrogen-fixing bacteria associated with Vetiver zizanioides. [Methods] Associated nitrogen-fixing bacteria isolated from Vetiver zizanioides were studied by SDS-PAGE wbole-cell protein patterns, insert sequence （IS）-PCR finger printing, utilization of sole carbon sources and 16S rRNA gene sequence analysis. [ Results] Based on the results of finger printing analysis, protein patterns and biological test, isolates were grouped into 6 clusters, except 4 single strains. Phylogenetic analysis of 16S rDNA sequences indicated that isolates belonged to Herbaspirillum frisingense, Enterobacter ludwigii, Pseudacidovorax intermedius, Mitsuaria chitosanitabida, Pseudomonas putida, Pseudomonas fluorescens, Burkholderia viemamiensis and Enterobacter cloacae. [ Conclusion] The nitrogen fixers associated with Vetiver zizanioides showed great diversity and may have a potential application for the grass forage and agriculture.