小叶满江红内生细菌DGGE及EM多样性分析

摘要：用16S rDNA-PCR-DGGE技术、电子显微镜和平板培养的方法系统地揭示小叶满江红（Azolla microphylla）中内生细菌的遗传多样性和表型多样性，根据16S rDNA-PCR-DGGE的指纹图谱，作者认为在小叶满江红－蓝藻共生体内存在一个以蜡质芽孢杆菌及其变种为优势种群的复杂、多样的微生物区系，内生细菌在体内呈现的各异的超微结构特征和体外培养生成的不同大小、形态和色素的菌落便是证明。文中也讨论了应用DGGE研究遗传多样性的优点、不足以及内生细菌在满江红－蓝藻共生体的系统发育和协同进化中的可能作用。

Diversity Analysis of Endophytic Bacteria within Azolla Microphylla using DGGE and EM

Abstract: Using 16S rDNA-PCR-DGGE, electron microscopy and conventional plating method, an attempt had been made to explore the genetic diversity and phenotype polymorphism of the endophytic bacteria within A.microphylla. Based on 16S rDNA-PCR-DGGE profile it is suggested that there is a complex and divergent bacterial community with Bacillus cereus and its variants as dominant species within Azolla-cyanobacteria association, which was supported by the fact that the endobacterial cells exhibited distinct ultrastructural characteristics in vivo and the bacteria appeared various colonies with different size, shape and colors in vitro. The advantage and limitation of using DGGE in uncovering genetic diversity and the potential role of endophtic bacteria in phylogeny and synchronic evolution among the Azolla, cyanobacteria and bacteria were discussed.