Krohn-Molt Ines, Alawi Malik, Förstner Konrad U, Wiegandt Alena, Burkhardt Lia, Indenbirken Daniela, Thieß Melanie, Grundhoff Adam, Kehr Julia, Tholey Andreas, Streit Wolfgang R
Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, Universität Hamburg, Hamburg, Germany.
Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Front Microbiol. 2017 Oct 10;8:1941. doi: 10.3389/fmicb.2017.01941. eCollection 2017.
Microalga are of high relevance for the global carbon cycling and it is well-known that they are associated with a microbiota. However, it remains unclear, if the associated microbiota, often found in phycosphere biofilms, is specific for the microalga strains and which role individual bacterial taxa play. Here we provide experimental evidence that , and , maintained in strain collections, are associated with unique and specific microbial populations. Deep metagenome sequencing, binning approaches, secretome analyses in combination with RNA-Seq data implied fundamental differences in the gene expression profiles of the microbiota associated with the different microalga. Our metatranscriptome analyses indicates that the transcriptionally most active bacteria with respect to key genes commonly involved in plant-microbe interactions in the Chlorella (Trebouxiophyceae) and Scenedesmus (Chlorophyceae) strains belong to the phylum of the α-Proteobacteria. In contrast, in the Micrasterias (Zygnematophyceae) phycosphere biofilm bacteria affiliated with the phylum of the Bacteroidetes showed the highest gene expression rates. We furthermore show that effector molecules known from plant-microbe interactions as inducers for the innate immunity are already of relevance at this evolutionary early plant-microbiome level.
微藻与全球碳循环高度相关，并且众所周知它们与微生物群有关。然而，尚不清楚在藻际生物膜中经常发现的相关微生物群是否对微藻菌株具有特异性，以及各个细菌类群发挥何种作用。在这里，我们提供了实验证据，保存在菌株库中的[具体微藻名称1]和[具体微藻名称2]与独特且特定的微生物种群相关。深度宏基因组测序、分箱方法、分泌蛋白质组分析与RNA测序数据相结合，暗示了与不同微藻相关的微生物群在基因表达谱上存在根本差异。我们的宏转录组分析表明，在小球藻（绿藻纲）和栅藻（绿藻纲）菌株中，在与植物-微生物相互作用中常见的关键基因方面转录活性最高的细菌属于α-变形菌门。相比之下，在微星鼓藻（接合藻纲）的藻际生物膜中，属于拟杆菌门的细菌显示出最高的基因表达率。我们还表明，在植物-微生物相互作用中作为先天免疫诱导剂而为人所知的效应分子在这个进化早期的植物-微生物群落水平上已经具有相关性。
