On the road to C4 rice: advances and perspectives
On the road to C4 rice: advances and perspectives
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DOI：
10.1111/tpj.14562
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发表时间：
2019-11-14
期刊：
影响因子：
7.2
通讯作者：
von Caemmerer, Susanne
中科院分区：
文献类型：
--
作者：
Ermakova, Maria;Danila, Florence R.;von Caemmerer, Susanne
国际C-4水稻联盟旨在将高能力光合机制，即C-4途径引入水稻，以提高产量。C-4途径的特征在于生物化学和解剖学专门化的复杂组合，其确保了束鞘（BS）细胞中RuBisCO位点处的高CO2分压。在此，我们报告C-4水稻项目的最新进展情况。自2008年成立以来，合成生物学和分子工具呈指数级增长。Golden Gate克隆和合成启动子系统促进了基因构建模块方法，允许从单个基因构建体组装和表达多种酶和代谢物转运蛋白。BS在水稻中的光合功能化仍然是一个重要的步骤，并且在影响叶绿体体积的细胞分裂素信号网络中过表达转录因子已经取得了一些成功。水稻C-4项目的开展，重新激发了人们对C-4光合作用的研究兴趣。比较解剖学研究现在指出了设计所必需的关键特征。到目前为止，很少有人注意到能量学。C-4光合作用具有更大的ATP需求，这是通过BS细胞中增加的循环电子传递来满足的。我们假设，能量状态的变化可能会驱动这种增加的循环电子流的能力，而不需要进一步的修改。虽然增加脉密度最终将是高效C-4水稻所必需的，但我们的模型表明，在现有脉周围引入少量的C-4光合作用已经可以在C-4水稻的道路上提供增加光合作用的好处。
The international C-4 rice consortium aims to introduce into rice a high capacity photosynthetic mechanism, the C-4 pathway, to increase yield. The C-4 pathway is characterised by a complex combination of biochemical and anatomical specialisation that ensures high CO2 partial pressure at RuBisCO sites in bundle sheath (BS) cells. Here we report an update of the progress of the C-4 rice project. Since its inception in 2008 there has been an exponential growth in synthetic biology and molecular tools. Golden Gate cloning and synthetic promoter systems have facilitated gene building block approaches allowing multiple enzymes and metabolite transporters to be assembled and expressed from single gene constructs. Photosynthetic functionalisation of the BS in rice remains an important step and there has been some success overexpressing transcription factors in the cytokinin signalling network which influence chloroplast volume. The C-4 rice project has rejuvenated the research interest in C-4 photosynthesis. Comparative anatomical studies now point to critical features essential for the design. So far little attention has been paid to the energetics. C-4 photosynthesis has a greater ATP requirement, which is met by increased cyclic electron transport in BS cells. We hypothesise that changes in energy statues may drive this increased capacity for cyclic electron flow without the need for further modification. Although increasing vein density will ultimately be necessary for high efficiency C-4 rice, our modelling shows that small amounts of C-4 photosynthesis introduced around existing veins could already provide benefits of increased photosynthesis on the road to C-4 rice.