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有效的 C4通路是基于 C3植物中发现的基因的强烈上调，但也将其表达区域化为不同的细胞类型，如叶肉和维管束鞘。与这些现象相关的转录因子还没有确定。为了解决这个问题，我们进行了全基因组分析，对 C4中的转录聚集、染色质可及性和转录因子结合进行了研究。 根据这些数据，提出了两个与 C4光合作用分子进化有关的模型。首先，C4基因表达的增加与 myb 相关转录因子结合的增加有关。其次，叶肉特异性表达与同源结构域转录因子的结合有关。总之，我们得出结论，在复杂 C4性状的进化过程中，C4循环基因获得了在 C3叶中运作的顺式元件，这些顺式元件被整合到与细胞特异性和光合作用有关的现有基因调控网络中。 Abstract: The efficient C4 pathway is based on strong up-regulation of genes found in C3 plants, but also compartmentation of their expression into distinct cell-types such as the mesophyll and bundle sheath. Transcription factors associated with these phenomena have not been identified. To address this, we undertook genome-wide analysis of transcript accumulation, chromatin accessibility and transcription factor binding in C4 Gynandropsis gynandra. From these data, two models relating to the molecular evolution of C4 photosynthesis are proposed. First, increased expression of C4 genes is associated with increased binding by MYB-related transcription factors. Second, mesophyll specific expression is associated with binding of homeodomain transcription factors. Overall, we conclude that during evolution of the complex C4 trait, C4 cycle genes gain cis-elements that operate in the C3 leaf such that they become integrated into existing gene regulatory networks associated with cell specificity and photosynthesis.
来源：biorxiv |
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