| Vitamin C (L-ascorbic acid, AsA) is one of the major non-enzyme antioxidants in plants. AsA works together with enzymes eliminating reactive oxygen species (ROS) generated from various conditions thus reduces oxidative damages. Besides, AsA is an essential component of human nutrition, which should be taken on daily basis. It would be resultable to increase of AsA yield in plants by genetic modifying, for on one hand the nutrition trait is enhanced, on the other hand the abilities to resist abiotic stress are built up.There have been considerable reports on AsA produced in plant via GDP-mannose pathway and glucuronate pathway. However, more and more researches reveal that crosslinks exist between AsA anabolism between plants and animals. Recently, it becomes interesting to explore how key enzyme from animal source works in AsA generation in plants. The L-gulono-gamma-lactone oxidase (GLOase, EC 1.1.3.8) is the last key enzyme in nature AsA synthesis in animal. In this research, for the first time Gulo, which encoded GLOase in Mus musculus, was transformed to Arabidopsis thaliana and studies focusing on abiotic stress were followed. Transgenetic Arabidopsis thaliana with 5.74μmol/g FW AsA was produced, which was 3.46 times of wild type (WT) and 3.19 times of blank transformation (CK). During drought stress under 30% PEG-6000, lower malondialdehyde (MDA) content was witmessed in transgenic A. thaliana plants, which was a demonstration of better anti-drought ability. Under 50mmol/L, 100mmol/L,150mmol/L,200mmol/L NaCl concentration respectively, transgenic Arabidopsis thaliana embodied better root development as well as lower MDA concentration, which were indexs of better salt tolerance.This study revealed the possibility of increasing plants AsA level by transforming animal sourced key enzyme, and analysed the abiotic tolerance such as salt and drought of AsA enhanced plants. Thus, the foundation of obtaining plants with high nutrition trait and high tolerance ability was built. |
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