Grosche Christopher, Genau Anne Christina, Rensing Stefan A
Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany.
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Front Plant Sci. 2018 Nov 6;9:1621. doi: 10.3389/fpls.2018.01621. eCollection 2018.
Arbuscular mycorrhiza is one of the most common plant symbiotic interactions observed today. Due to their nearly ubiquitous occurrence and their beneficial impact on both partners it was suggested that this mutualistic interaction was crucial for plants to colonize the terrestrial habitat approximately 500 Ma ago. On the plant side the association is established via the common symbiotic pathway (CSP). This pathway allows the recognition of the fungal symbiotic partner, subsequent signaling to the nucleus, and initiation of the symbiotic program with respect to specific gene expression and cellular re-organization. The downstream part of the CSP is a regulatory network that coordinates the transcription of genes necessary to establish the symbiosis, comprising multiple GRAS transcription factors (TFs). These regulate their own expression as an intricate transcriptional network. Deduced from non-host genome data the loss of genes encoding CSP components coincides with the loss of the interaction itself. Here, we analyzed bryophyte species with special emphasis on the moss , supposed to be a non-host, for the composition of the GRAS regulatory network components. We show lineage specific losses and expansions of several of these factors in bryophytes, potentially coinciding with the proposed host/non-host status of the lineages. We evaluate losses and expansions and infer clade-specific evolution of GRAS TFs.
丛枝菌根是当今观察到的最常见的植物共生相互作用之一。由于它们几乎无处不在，并且对双方都有有益影响，有人认为这种互利共生相互作用对于植物大约在5亿年前殖民陆地栖息地至关重要。在植物方面，这种关联是通过共同共生途径（CSP）建立的。该途径允许识别真菌共生伙伴，随后向细胞核发出信号，并启动关于特定基因表达和细胞重组的共生程序。CSP的下游部分是一个调控网络，它协调建立共生所需基因的转录，包括多个GRAS转录因子（TFs）。这些因子作为一个复杂的转录网络调节它们自身的表达。从非宿主基因组数据推断，编码CSP成分的基因的丧失与相互作用本身的丧失同时发生。在这里，我们特别分析了苔藓植物，尤其是被认为是非宿主的苔藓，以研究GRAS调控网络成分的组成。我们展示了苔藓植物中这些因子中的几个在谱系特异性上的丧失和扩展，这可能与所提出的谱系的宿主/非宿主状态一致。我们评估了丧失和扩展情况，并推断了GRAS TFs的分支特异性进化。
