Department of Microbiology, School of Life Sciences, Bharathidasan University, Tiruchirappalli Tamilnadu, India.
J Basic Microbiol. 2010 Jun;50(3):254-65. doi: 10.1002/jobm.200900343.
The morphological and genetic diversity of cyanobacteria associated with cycads was examined using PCR amplification techniques and 16S rRNA gene sequence analysis. Eighteen symbiotic cyanobacteria were isolated from different cycad species. One of the symbiotic isolates was a species of Calothrix, a genus not previously reported to form symbioses with Cycadaceae family, and the remainder were Nostoc spp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the repetitive sequences. Based on fingerprint patterns and phenograms, it was revealed that cyanobacterial symbionts exhibit important genetic diversity among host plants, both within and between cycad populations. A phylogenetic analysis based on 16S rRNA gene sequence analysis revealed that most of the symbiotic cyanobacterial isolates fell into well-separated clades.
采用 PCR 扩增技术和 16S rRNA 基因序列分析，研究了与苏铁共生的蓝藻的形态和遗传多样性。从不同的苏铁物种中分离出了 18 种共生蓝藻。其中一个共生种是一种未曾报道过与苏铁科形成共生关系的念珠藻属，其余的是念珠藻属。利用短随机引物或重复序列特异性引物进行 PCR 扩增，比较了无菌蓝藻菌株。根据指纹图谱和系统发育树，表明蓝藻共生体在宿主植物之间和内部表现出重要的遗传多样性。基于 16S rRNA 基因序列分析的系统发育分析表明，大多数共生蓝藻分离株属于不同的分支。
