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

我们正试图通过向高生物量植物引入重金属抗性基因来改善重金属抗性植物。在这项研究中，我们过表达酵母CUP1基因以增加红麻金属硫蛋白的合成。接下来，我们将CSase基因CS3F引入红麻，构建了过表达CSase的转基因植株，以证实CSase活性与红麻抗酸性土壤的相关性。转基因红麻的CSase活性是野生型红麻的10倍左右。添加硫酸盐离子后，野生型红麻的CSase活性提高了5 ~ 6倍。然而，转基因红麻的CSase活性在硫酸盐离子存在下并没有增加。因此，转基因红麻植株显示出持续较高的CSase活性。野生型红麻在低ph （pH3.7m富重金属）土壤中的生长受到极大的抑制，而转基因红麻在pH6.1土壤中的生长几乎与对照土壤相同。此外，野生型红麻在低ph土壤中证实了黄化症状，而转基因红麻没有出现黄化症状。在酸性土壤中生长的野生型和转基因红麻体内重金属（Cu、Zn、Fe、Mn）浓度均有所升高。由此，我们推测野生型红麻的黄化是由于重金属的积累造成的，而半胱氨酸或其衍生物由于某种未知的原因使过量的重金属无害。研究了半胱氨酸合成能力增强对重金属耐受性的影响。当Cd浓度为50 μM或100 μM时，转基因红麻的生长较野生型红麻好。尽管Cd浓度较高，但转基因红麻的生长并未受到抑制，这说明半胱氨酸在转基因红麻中具有解毒Cd的作用。综上所述，这些转基因植株不仅合成半胱氨酸的能力增强，而且对Al、Cd和酸性条件的耐受性也增强。因此，半胱氨酸合成能力增强的植物应能抵抗各种形式的胁迫。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