Promoted functional enhancement of heavy metal tolerant plant and purification of heavy metal contaminated soil by it.

我们正在努力通过将与重金属耐受性有关的基因引入高生物量植物来提高植物的重金属耐受性。在本研究中，我们过表达了酵母CUP1基因，以增加红麻中金属硫蛋白的合成。接下来，我们通过将CSase基因CS3F导入红麻，构建了过量表达CSase的转基因植株，以证实CSase活性与对酸性土壤的抗性之间的关系。当测定转基因红麻的CSase活性时，其值大约是野生型红麻的10倍。供应硫酸盐离子时，野生型红麻的CSase活性提高5~6倍。然而，在硫酸盐离子存在下，转基因红麻的CSase活性并没有增加。因此，转基因红麻植株表现出持续较高的CSase活性。在低pH值土壤(富含重金属的pH值为3.7M)中，野生型的生长受到极大的抑制，而t…的生长则受到严重的抑制更多的转基因红麻与对照土壤(pH 6.1)的生长基本相同。此外，在低pH土壤中，野生型红麻出现了黄化症状，而转基因红麻则未出现黄化症状。在酸性土壤中生长的野生型红麻和转基因红麻体内的重金属(铜、锌、铁、锰)浓度均升高。根据这一事实，我们推测野生红麻中观察到的黄化是由于重金属的积累，半胱氨酸或其衍生物使过量的重金属出于某种未知的原因而变得无害。此外，还考察了半胱氨酸合成能力增强对重金属耐受性的影响。与野生型红麻相比，转基因红麻在50或100μM-Cd处理下生长良好。尽管Cd浓度较高，但生长没有受到抑制，这表明半胱氨酸能够解毒转基因Kenaf.综上所述，这些转基因植株不仅提高了合成半胱氨酸的能力，而且提高了对Al、Cd和酸性条件的耐受性.因此，半胱氨酸合成能力增强的植物应该表现出对各种形式的胁迫的抗性。较少

We are tying to improve heavy-metal tolerance plants by introducing genes involved in heavy-metal tolerance to plants with high biomass. In this study, we overexpressed the yeast CUP1 gene to increase metallothionein synthesis in kenaf (Hibiscus cannabinus). Next, we constructed a transgenic plant that overexpressed CSase by introducing CSase gene CS3F into the kenaf, in order to confirm this correlation between CSase activity and resistance toward acidic soil. When the CSase activity of the transgenic kenaf was measured, it showed a value approximately 10 times that of the wild-type kenaf. The CSase activity of the wild-type kenaf increased 5-6 times, when sulfate ions were supplied. However, the CSase activity of the transgenic kenaf was not increased in the presence of sulfate ions. Therefore, the transgenic kenaf plant showed a CSase activity that was constantly high. The growth of the wild-type was greatly reduced in the low-pH soil (pH3.7m heavy metal rich), whereas that of the t … More ransgenic kenaf was almost the same as the growth in the control soil (pH6.1). Moreover, the chlorosis symptom was confirmed in the wild-type kenaf in the low-pH soil, but was not seen in the transgenic kenaf. the internal concentrations of heavy metals (Cu, Zn, Fe, Mn) also increased in both the wild-type and transgenic kenaf growing in the acidic soil. From this fact, we suppose that the chlorosis observed in the wild-type kenaf was due to the accumulated heavy metals and that cysteine or some derivatve of it made the excessive heavy metal harmless for some unknown reason. The influence of strengthened cystein-synthesizing ability on heavy-metal tolerance was also examined. The transgenic kenaf showed good growth compared with the wild-type kenaf when treated with 50 or 100 μM Cd. The fact that growth was not suppressed despite the high Cd concentration indicates that cysteine is able to detoxify Cd in the transgenic kenaf.In conclusion, these transgenic plants showed not only strengthened ability to synthesize cysteine but also increased tolerance toward Al, Cd, and acidic conditions. Thus, plants with increased cysteine-synthesizing ability should show resistance against various forms of stress. Less