Loss of GLK1 transcription factor function reveals new insights in chlorophyll biosynthesis and chloroplast development
Loss of GLK1 transcription factor function reveals new insights in chlorophyll biosynthesis and chloroplast development
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GLK1转录因子功能的丧失揭示了叶绿素生物合成和叶绿体发育的新见解
DOI：
10.1093/jxb/erz128
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发表时间：
2019-06-01
影响因子：
6.9
通讯作者：
Jiang, Jing
中科院分区：
文献类型：
--
作者：
Gang, Huixin;Li, Ranhong;Jiang, Jing
白桦（Betula platyphylla x B.垂盆草是一种重要的园林绿化树种，因其白色树皮和笔直的树干而引人注目。在这项研究中，我们表征了T-DNA黄绿叶突变体，yl。我们通过基因组重测序确定了突变体中的6个插入位点（IS），并在2号染色体上的IS 2周围发现了一个40 kb的含有BpGLK 1的缺失。与yl突变体的互补实验和野生型植物中BpGLK 1的阻遏证实了BpGLK 1是突变表型的原因。生理和超微结构分析表明，叶片的yl突变体和BpGLK 1-阻遏线有降低的叶绿素含量和有缺陷的叶绿体发育相比，野生型。此外，BpGLK 1功能的丧失也影响了叶片的光合作用。转录组学、蛋白质组学和ChIP-PCR分析表明，BpGLK 1直接与天线蛋白、叶绿素合成和光系统亚基合成相关基因的启动子相互作用，调控其表达。总之，我们的研究不仅为BpGLK 1调控叶绿体发育和叶绿素生物合成的机制提供了新的见解，而且还通过抑制BpGLK 1表达提供了具有不同水平黄化叶片的新的转基因桦树品种。
Birch (Betula platyphylla x B. pendula) is an important tree for landscaping due to its attractive white bark and straight trunk. In this study, we characterized a T-DNA yellow-green leaf mutant, yl. We identified six insertion sites (ISs) in the mutant by genome resequencing and found a 40-kb deletion containing BpGLK1 around IS2 on chromosome 2. Complementation experiments with the yl mutant and repression of BpGLK1 in wild-type plants confirmed that BpGLK1 was responsible for the mutated phenotype. Physiological and ultrastructural analyses showed that the leaves of the yl mutant and BpGLK1-repression lines had decreased chlorophyll content and defective chloroplast development compared to the wild-type. Furthermore, the loss function of BpGLK1 also affected photosynthesis in leaves. Transcriptomics, proteomics, and ChIP-PCR analysis revealed that BpGLK1 directly interacted with the promoter of genes related to antenna proteins, chlorophyll biosynthesis, and photosystem subunit synthesis, and regulated their expression. Overall, our research not only provides new insights into the mechanism of chloroplast development and chlorophyll biosynthesis regulated by BpGLK1, but also provides new transgenic birch varieties with various levels of yellowing leaves by repressing BpGLK1 expression.