Li Yuan, Dong Xiu-Mei, Jin Feng, Shen Zhuo, Chao Qing, Wang Bai-Chen
Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of SciencesBeijing, China.
State Key Laboratory of Forest Genetics and Tree Breeding, Northeast Forestry UniversityHarbin, China.
Front Plant Sci. 2017 Jun 8;8:950. doi: 10.3389/fpls.2017.00950. eCollection 2017.
Histone modifications play important roles in regulating the expression of C photosynthetic genes. Given that all enzymes required for the C photosynthesis pathway are present in C plants, it has been hypothesized that this expression regulatory mechanism has been conserved. However, the relationship between histone modification and the expression of homologs of C photosynthetic enzyme genes has not been well determined in C plants. In the present study, we cloned nine hybrid poplar ( × ) homologs of maize () C photosynthetic enzyme genes, (), (), (), and (), and investigated the correlation between the expression levels of these genes and the levels of promoter histone acetylation modifications in four vegetative tissues. We found that poplar homologs of C homologous genes had tissue-dependent expression patterns that were mostly well-correlated with the level of histone acetylation modification (H3K9ac and H4K5ac) determined by chromatin immunoprecipitation assays. Treatment with the histone deacetylase inhibitor trichostatin A further confirmed the role of histone acetylation in the regulation of the nine target genes. Collectively, these results suggest that both H3K9ac and H4K5ac positively regulate the tissue-dependent expression pattern of the , , , and genes and that this regulatory mechanism seems to be conserved among the C and C species. Our findings provide new insight that will aid efforts to modify the expression pattern of these homologs of C genes to engineer C plants from C plants.
组蛋白修饰在调控C4光合基因的表达中发挥着重要作用。鉴于C4光合作用途径所需的所有酶都存在于C4植物中，因此有人推测这种表达调控机制是保守的。然而，在C4植物中，组蛋白修饰与C4光合酶基因同源物表达之间的关系尚未得到很好的确定。在本研究中，我们克隆了玉米（Zea mays）C4光合酶基因磷酸烯醇式丙酮酸羧化酶（PEPC）、丙酮酸磷酸双激酶（PPDK）、苹果酸脱氢酶（MDH）和磷酸烯醇式丙酮酸羧化激酶（PEPCK）的9个杂种杨树（Populus×euramericana）同源物，并研究了这些基因在四个营养组织中的表达水平与启动子组蛋白乙酰化修饰水平之间的相关性。我们发现，C4同源基因的杨树同源物具有组织依赖性表达模式，这些模式大多与通过染色质免疫沉淀分析确定的组蛋白乙酰化修饰（H3K9ac和H4K5ac）水平密切相关。用组蛋白去乙酰化酶抑制剂曲古抑菌素A处理进一步证实了组蛋白乙酰化在调控这9个靶基因中的作用。总体而言，这些结果表明，H3K9ac和H4K5ac均正向调控PEPC、PPDK、MDH和PEPCK基因的组织依赖性表达模式，并且这种调控机制在C3和C4物种中似乎是保守的。我们的研究结果提供了新的见解，将有助于努力改变这些C4基因同源物的表达模式，从而从C3植物培育出C4植物。
