Zhou Shengen, Xiao Sunqin, Xuan Xiuxia, Sun Zhen, Li Kunzhi, Chen Limei
Faculty of Life Science and Biotechnology, Kunming University of Science and Technology, Chenggong, Kunming 650500, PR China.
Faculty of Life Science and Biotechnology, Kunming University of Science and Technology, Chenggong, Kunming 650500, PR China.
Plant Physiol Biochem. 2015 Apr;89:53-63. doi: 10.1016/j.plaphy.2015.02.009. Epub 2015 Feb 14.
The overexpression of dihydroxyacetone synthase (DAS) and dihydroxyacetone kinase (DAK) from methylotrophic yeasts in chloroplasts created a photosynthetic formaldehyde (HCHO)-assimilation pathway (DAS/DAK pathway) in transgenic tobacco. Geranium has abilities to absorb and metabolize HCHO. Results of this study showed that the installed DAS/DAK pathway functioning in chloroplasts greatly enhanced the role of the Calvin cycle in transgenic geranium under high concentrations of gaseous HCHO stress. Consequently, the yield of sugars from HCHO-assimilation increased approximately 6-fold in transgenic geranium leaves, and concomitantly, the role of three original HCHO metabolic pathways reduced, leading to a significant decrease in formic acid, citrate and glycine production from HCHO metabolism. Although the role of three metabolic pathways reduced in transgenic plants under high concentrations of gaseous HCHO stress, the installed DAS/DAK pathway could still function together with the original HCHO metabolic pathways. Consequently, the gaseous HCHO-resistance of transgenic plants was significantly improved, and the generation of H2O2 in the transgenic geranium leaves was significantly less than that in the wild type (WT) leaves. Under environmental-polluted gaseous HCHO stress for a long duration, the stomata conductance of transgenic plants remained approximately 2-fold higher than that of the WT, thereby increasing its ability to purify gaseous HCHO polluted environment.
在叶绿体中过表达甲基营养型酵母的二羟基丙酮合酶（DAS）和二羟基丙酮激酶（DAK），在转基因烟草中创建了一条光合甲醛（HCHO）同化途径（DAS/DAK途径）。天竺葵具有吸收和代谢HCHO的能力。本研究结果表明，在叶绿体中起作用的已安装DAS/DAK途径在高浓度气态HCHO胁迫下极大地增强了转基因天竺葵中卡尔文循环的作用。因此，转基因天竺葵叶片中HCHO同化产生的糖产量增加了约6倍，同时，三种原始HCHO代谢途径的作用减弱，导致HCHO代谢产生的甲酸、柠檬酸和甘氨酸产量显著下降。虽然在高浓度气态HCHO胁迫下转基因植物中三种代谢途径的作用减弱，但已安装的DAS/DAK途径仍可与原始HCHO代谢途径一起发挥作用。因此，转基因植物的气态HCHO抗性显著提高，转基因天竺葵叶片中H2O2的产生明显少于野生型（WT）叶片。在长期受环境污染的气态HCHO胁迫下，转基因植物的气孔导度比WT高出约2倍，从而提高了其净化气态HCHO污染环境的能力。
