三种重金属对中华稻蝗金属硫蛋白基因表达的影响

以栖息于稻田且主要取食水稻茎叶的中华稻蝗(Oxya chinensis)成虫为供试材料,经氯化镉、氯化铜和硫酸锌(Cd Cl2、Cu Cl2和Zn SO4)3种重金属急性染毒,采用RT-q PCR技术检测中华稻蝗2个金属硫蛋白基因(Oxya chinensis metallothionein,Oc MT1,Oc MT2)在精巢、卵巢和肌肉中的表达变化。结果表明,3种重金属均可诱导中华稻蝗MT基因不同程度的上调表达。经Cd急性处理后,3个器官组织中Oc MT1和Oc MT2表达水平在一定浓度范围内随着Cd浓度的增高而诱导表达上调;经Cu急性处理后,精巢和卵巢中Oc MT1在最低浓度时的诱导表达量最高,Oc MT2表达水平随着Cu浓度的增大而升高,肌肉中2个MT基因随着Cu浓度的增大而升高;经Zn处理后,Oc MT1和Oc MT2表达水平随着Zn浓度的升高而升高。由实验结果可以看出,3种重金属对中华稻蝗MT在不同器官组织均有诱导表达作用,但各浓度处理后其诱导表达水平不同,Oc MT对不同重金属的敏感性具有显著差异。

Effects of Three Heavy Metals on mRNA Expressions of Two Metallothioneins in Oxya chinensis

Oxya chinensis is an important agricultural pest and feeds mainly on rice. Adults of O. chinensis were treated with three heavy metals(CdCl2, CuCl2 and ZnSO4), respectively. Quantitative real-time PCR(qPCR) was used to measure OcMT1 and OcMT2 expressions in testis, ovary and muscle of O. chinensis. In the Cd treatments, mRNA levels of OcMT in three tissues were significantly up-regulated in a dose-dependent manner, compared to the control. However, the greatest expression of OcMT1 in testis and ovary was found at the lowest Cu concentration, while the expression of OcMT2 in three tissues increased significantly with Cu concentrations. Zinc treatments increased OcMT1 and OcMT2 expression levels in three tissues in a dose-dependent manner. These results show that the OcMT1 and OcMT2 in testis, ovary and muscle could be induced by three heavy metals, but their mRNA expression levels are different at different concentrations of heavy metals. OcMTs show different sensitivities to different heavy metals. The expressions and synthesis of MT induced by heavy metals would be of significance in protecting tissues by reducing toxicity of metals via binding with MT, which advances our understanding of how this insect deals with excessive heavy metals at molecular levels.