Institute of Plant Molecular and Developmental Biology, Heinrich-Heine University, Universitätsstrasse 1, 40225, Duesseldorf, Germany.
Cluster of Excellence on Plant Sciences 'From Complex Traits towards Synthetic Modules', 40225 Duesseldorf and, 50923, Cologne, Germany.
Plant J. 2019 Mar;97(5):984-995. doi: 10.1111/tpj.14165. Epub 2019 Jan 18.
The evolution of C photosynthesis proceeded stepwise with each small step increasing the fitness of the plant. An important pre-condition for the introduction of a functional C cycle is the photosynthetic activation of the C bundle sheath by increasing its volume and organelle number. Therefore, to engineer C photosynthesis into existing C crops, information about genes that control the bundle sheath cell size and organelle content is needed. However, very little information is known about the genes that could be manipulated to create a more C -like bundle sheath. To this end, an ethylmethanesulfonate (EMS)-based forward genetic screen was established in the Brassicaceae C species Arabidopsis thaliana. To ensure a high-throughput primary screen, the bundle sheath cells of A. thaliana were labeled using a luciferase (LUC68) or by a chloroplast-targeted green fluorescent protein (sGFP) reporter using a bundle sheath specific promoter. The signal strengths of the reporter genes were used as a proxy to search for mutants with altered bundle sheath anatomy. Here, we show that our genetic screen predominantly identified mutants that were primarily affected in the architecture of the vascular bundle, and led to an increase in bundle sheath volume. By using a mapping-by-sequencing approach the genomic segments that contained mutated candidate genes were identified.
C 光合作用的进化是逐步进行的，每一小步都能提高植物的适应性。引入功能性 C 循环的一个重要前提条件是通过增加 C 束鞘的体积和细胞器数量来激活其光合作用。因此，要将 C 光合作用工程化到现有的 C 作物中，就需要了解控制束鞘细胞大小和细胞器含量的基因信息。然而，对于可以用来创造更像 C 的束鞘的基因，我们知之甚少。为此，在十字花科 C 种拟南芥中建立了基于乙基磺酸乙酯（EMS）的正向遗传筛选。为了确保高通量的初步筛选，使用荧光素酶（LUC68）或叶绿体靶向绿色荧光蛋白（sGFP）报告基因通过束鞘特异性启动子标记拟南芥的束鞘细胞。报告基因的信号强度被用作寻找具有改变的束鞘解剖结构的突变体的替代指标。在这里，我们表明，我们的遗传筛选主要识别出主要影响维管束结构的突变体，并导致束鞘体积增加。通过使用基于测序的映射方法，鉴定出包含突变候选基因的基因组片段。
