Institute of Biology Leiden, Faculty of Science, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
BioSolar Cells, P.O. Box 98, 6700 AB, Wageningen, The Netherlands.
Sci Rep. 2017 Jun 12;7(1):3314. doi: 10.1038/s41598-017-03611-1.
The overall light energy to biomass conversion efficiency of plant photosynthesis is generally regarded as low. Forward genetic screens in Arabidopsis have yielded very few mutants with substantially enhanced photochemistry. Here, we report the isolation of a novel Arabidopsis mutant with a high operating efficiency of Photosystem II (φPSII) and low chlorophyll fluorescence from a library of lines harboring T-DNA constructs encoding artificial transcription factors. This mutant was named Low Chlorophyll Fluorescence 1 (LCF1). Only a single T-DNA insertion was detected in LCF1, which interrupted the expression of the full length mRNA of the gene At4g36280 (MORC2). We demonstrate that the high φPSII and low levels of chlorophyll fluorescence were due to a decrease in PSII:PSI ratio. Although LCF1 plants had decreased rosette surface area and biomass under normal growth conditions, they contained more starch per gram fresh weight. The growth defect of LCF1 was alleviated by low light and short day conditions, and growth could even be enhanced after a period of dark-induced senescence, showing that the plant can utilize its excess photosynthetic conversion capacity as a resource when needed.
植物光合作用的整体光能到生物质转换效率通常被认为较低。拟南芥的正向遗传学筛选仅产生了少数光合作用显著增强的突变体。在这里，我们报道了一种新型拟南芥突变体的分离，该突变体具有高的光合系统 II （φPSII）操作效率和低叶绿素荧光，该突变体来自携带编码人工转录因子的 T-DNA 构建体的品系文库。该突变体被命名为低叶绿素荧光 1（LCF1）。在 LCF1 中仅检测到单个 T-DNA 插入，该插入中断了基因 At4g36280（MORC2）全长 mRNA 的表达。我们证明高 φPSII 和低叶绿素荧光水平是由于 PSII：PSI 比率降低所致。尽管 LCF1 植物在正常生长条件下的莲座叶面积和生物量减少，但每克鲜重含有更多的淀粉。LCF1 的生长缺陷可以通过低光照和短日照条件得到缓解，并且在黑暗诱导衰老后的一段时间后甚至可以增强生长，这表明植物可以在需要时将其多余的光合作用转换能力用作资源。
