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    朱智梅, 张玉红, 撒刚, 刘建, 马旭君, 邓晨, 赵瑞, 陈少良. 外生菌根真菌Paxillus involutus吸收Cd2+及H2O2对Cd2+内流的调控作用[J]. 北京林业大学学报, 2018, 40(4): 24-32. DOI: 10.13332/j.1000-1522.20170418
    引用本文: 朱智梅, 张玉红, 撒刚, 刘建, 马旭君, 邓晨, 赵瑞, 陈少良. 外生菌根真菌Paxillus involutus吸收Cd2+及H2O2对Cd2+内流的调控作用[J]. 北京林业大学学报, 2018, 40(4): 24-32. DOI: 10.13332/j.1000-1522.20170418
    Zhu Zhimei, Zhang Yuhong, Sa Gang, Liu Jian, Ma Xujun, Deng Chen, Zhao Rui, Chen Shaoliang. Uptake of Cd2+ by ectomycorrhizal fungus Paxillus involutus and the modulation of H2O2 in Cd2+ influx[J]. Journal of Beijing Forestry University, 2018, 40(4): 24-32. DOI: 10.13332/j.1000-1522.20170418
    Citation: Zhu Zhimei, Zhang Yuhong, Sa Gang, Liu Jian, Ma Xujun, Deng Chen, Zhao Rui, Chen Shaoliang. Uptake of Cd2+ by ectomycorrhizal fungus Paxillus involutus and the modulation of H2O2 in Cd2+ influx[J]. Journal of Beijing Forestry University, 2018, 40(4): 24-32. DOI: 10.13332/j.1000-1522.20170418

    外生菌根真菌Paxillus involutus吸收Cd2+及H2O2对Cd2+内流的调控作用

    Uptake of Cd2+ by ectomycorrhizal fungus Paxillus involutus and the modulation of H2O2 in Cd2+ influx

    • 摘要:
      目的本文研究了外生菌根真菌Paxillus involutus对Cd2+的吸收作用以及H2O2对Cd2+内流的调控作用。
      方法Paxillus involutus的2种菌株MAJ和NAU为研究材料,利用50 μmol/L CdCl2对材料进行24 h处理,应用非损伤微测技术测定菌丝的Cd2+和Ca2+离子流。
      结果结果显示,Cd2+处理后,MAJ和NAU菌丝的Cd2+内流增强,同时也显著促进了Ca2+的内流。Ca2+通道抑制剂(Verapamil、GdCl3、TEA)处理后,Cd2+和Ca2+内流强度均明显减弱,表明Cd2+是通过钙通透性离子通道(CaPCs)进入菌丝细胞的。Cd2+处理促进了Cd2+和Ca2+的内流,很可能是Cd2+激活了菌丝质膜的CaPCs。Ca2+和Cd2+的竞争性实验结果显示,高浓度的Ca2+抑制菌株MAJ和NAU的Cd2+内流;反过来,测试液中Cd2+浓度的提高也明显降低了Ca2+的内流强度,这证明Ca2+和Cd2+是竞争性地通过CaPCs进入菌丝细胞的。此外还发现,H2O2(1.0 mmol/L)能增强菌丝的Cd2+和Ca2+内流,而ROS清除剂DMTU却显著抑制了菌株对Ca2+和Cd2+的吸收,表明H2O2在调控菌丝细胞CaPCs介导Cd2+内流的过程中具有重要作用。
      结论 综上,外生菌根真菌Paxillus involutus对Cd2+具有富集作用并且可以通过H2O2激活CaPCs促进Cd2+内流。

       

      Abstract:
      ObjectiveThe uptake of Cd2+ by ectomycorrhizal fungus Paxillus involutus and the modulation of H2O2 in Cd2+ influx were investigated in this study.
      Method Two Paxillus involutus strains, MAJ and NAU, were subjected to 50 μmol/L CdCl2 for 24 hours, and then fluxes of Ca2+ and Cd2+ were examined by non-invasive micro-test technique.
      Result The results showed that Cd2+ treatment caused the Cd2+ influx, and the Ca2+ influx was also significantly enhanced by Cd2+ in MAJ and NAU hyphae. However, the Cd2+-elicited influxes of Cd2+ and Ca2+ were both restricted by Ca2+ channel inhibitors including Verapamil, GdCl3, TEA (Tetraethylammonium), indicating that Cd2+ and Ca2+ simultaneously entered the hyphal cell through plasma membrane (PM) Ca2+-permeable channels (CaPCs). The promotion of Ca2+ by Cd2+ implied that Cd2+ activated CaPCs, thus leading to an increased entry of Ca2+, in addition to Cd2+. Moreover competitive inhibition experiments were also conducted to verify whether Cd2+ and Ca2+ entered into the mycelium through CaPCs in the PM. The influx of Cd2+ in MAJ and NAU was lowered by increased concentration of Ca2+, and vice versa. Therefore, Cd2+ and Ca2+ competitively permeated the plasma membrane through Ca2+-permeable channels. Additionally, the influxes of Ca2+ and Cd2+ in mycelium were enhanced by 1 mmol/L H2O2 while suppressed by the ROS scavenger, DMTU (N, N′-Dimethylthiourea). This indicated that H2O2 could mediate the entry of Cd2+ through PM Ca2+-permeable channels in fungal hyphae.
      Conclusion In conclusion, the ectomycorrhizal fungus Paxillus involutus has the ability of Cd2+ enrichment and the influx of Cd2+ can be facilitated through CaPCs activated by H2O2.

       

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