Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia.
ISME J. 2010 Feb;4(2):301-11. doi: 10.1038/ismej.2009.107. Epub 2009 Oct 15.
Marine Ulvacean algae are colonized by dense microbial communities predicted to have an important role in the development, defense and metabolic activities of the plant. Here we assess the diversity and seasonal dynamics of the bacterial community of the model alga Ulva australis to identify key groups within this epiphytic community. A total of 48 algal samples of U. australis that were collected as 12 individuals at 3 monthly intervals, were processed by applying denaturing gradient gel electrophoresis (DGGE), and three samples from each season were subjected to catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). CARD-FISH revealed that the epiphytic microbial community was comprised mainly of bacterial cells (90%) and was dominated by the groups Alphaproteobacteria (70%) and Bacteroidetes (13%). A large portion (47%) of sequences from the Alphaproteobacteria fall within the Roseobacter clade throughout the different seasons, and an average relative proportion of 19% was observed using CARD-FISH. DGGE based spatial (between tidal pools) and temporal (between season) comparisons of bacterial community composition demonstrated that variation occurs. Between individuals from both the same and different tidal pools, the variation was highest during winter (30%) and between seasons a 40% variation was observed. The community also includes a sub-population of bacteria that is consistently present. Sequences from excised DGGE bands indicate that members of the Alphaproteobacteria and the Bacteroidetes are part of this stable sub-population, and are likely to have an important role in the function of this marine epiphytic microbial community.
海洋绿藻被密集的微生物群落定殖，这些微生物群落被预测对植物的发育、防御和代谢活动具有重要作用。在这里，我们评估了模式海藻 U. australis 的细菌群落的多样性和季节性动态，以确定这个附生群落中的关键群体。总共采集了 48 个 U. australis 藻类样本，每个样本采集 12 个个体，每隔 3 个月采集一次，通过变性梯度凝胶电泳 (DGGE) 进行处理，每个季节的 3 个样本进行催化报告物沉积荧光原位杂交 (CARD-FISH)。CARD-FISH 显示，附生微生物群落主要由细菌细胞组成（90%），并以α变形菌（70%）和拟杆菌门（13%）为主导。在不同季节，α变形菌的大部分序列（47%）都属于玫瑰杆菌群，CARD-FISH 观察到的平均相对比例为 19%。基于 DGGE 的细菌群落组成的空间（在潮汐池之间）和时间（在季节之间）比较表明存在变异。在来自同一和不同潮汐池的个体之间，冬季变异最大（30%），而季节之间的变异为 40%。该群落还包括一个始终存在的细菌亚群。从切除的 DGGE 条带获得的序列表明，α变形菌和拟杆菌门的成员是这个稳定亚群的一部分，可能在这个海洋附生微生物群落的功能中发挥重要作用。
