Biological Sciences Division, Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory Richland, WA, USA.
Chemical, Biological, and Physical Sciences Division, National Security Directorate, Pacific Northwest National Laboratory Richland, WA, USA.
Front Microbiol. 2014 Apr 7;5:109. doi: 10.3389/fmicb.2014.00109. eCollection 2014.
Microbial autotroph-heterotroph interactions influence biogeochemical cycles on a global scale, but the diversity and complexity of natural systems and their intractability to in situ manipulation make it challenging to elucidate the principles governing these interactions. The study of assembling phototrophic biofilm communities provides a robust means to identify such interactions and evaluate their contributions to the recruitment and maintenance of phylogenetic and functional diversity over time. To examine primary succession in phototrophic communities, we isolated two unicyanobacterial consortia from the microbial mat in Hot Lake, Washington, characterizing the membership and metabolic function of each consortium. We then analyzed the spatial structures and quantified the community compositions of their assembling biofilms. The consortia retained the same suite of heterotrophic species, identified as abundant members of the mat and assigned to Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes. Autotroph growth rates dominated early in assembly, yielding to increasing heterotroph growth rates late in succession. The two consortia exhibited similar assembly patterns, with increasing relative abundances of members from Bacteroidetes and Alphaproteobacteria concurrent with decreasing relative abundances of those from Gammaproteobacteria. Despite these similarities at higher taxonomic levels, the relative abundances of individual heterotrophic species were substantially different in the developing consortial biofilms. This suggests that, although similar niches are created by the cyanobacterial metabolisms, the resulting webs of autotroph-heterotroph and heterotroph-heterotroph interactions are specific to each primary producer. The relative simplicity and tractability of the Hot Lake unicyanobacterial consortia make them useful model systems for deciphering interspecies interactions and assembly principles relevant to natural microbial communities.
微生物自养-异养相互作用在全球范围内影响着生物地球化学循环，但自然系统的多样性和复杂性及其对原位操作的难以处理性，使得阐明控制这些相互作用的原则具有挑战性。研究光合生物膜群落的组装提供了一种强有力的方法，可以识别这些相互作用，并评估它们对时间推移中系统发育和功能多样性的招募和维持的贡献。为了研究光合生物群落中的原生演替，我们从华盛顿州霍特湖的微生物席中分离出两个单氰细菌联合体，对每个联合体的成员和代谢功能进行了表征。然后，我们分析了它们组装生物膜的空间结构并量化了其群落组成。这些联合体保留了相同的异养物种，这些物种被鉴定为席中的丰富成员，并被归类为α变形菌、γ变形菌和拟杆菌门。在组装的早期，自养生物的生长速率占主导地位，随后在演替的后期，异养生物的生长速率增加。两个联合体表现出相似的组装模式，随着拟杆菌门和α变形菌门成员的相对丰度增加，γ变形菌门成员的相对丰度减少。尽管在更高的分类学水平上存在这些相似性，但在发育中的联合体生物膜中，个别异养物种的相对丰度却大不相同。这表明，尽管蓝细菌代谢作用创造了相似的小生境，但由此产生的自养-异养和异养-异养相互作用网络是特定于每个初级生产者的。霍特湖单氰细菌联合体相对简单且易于处理，因此它们是用于破译与自然微生物群落相关的种间相互作用和组装原则的有用模型系统。
