Desorption of zinc by extracellularly produced metabolites of Trichoderma harzianum, Trichoderma reesei and Coriolus versicolor
Desorption of zinc by extracellularly produced metabolites of Trichoderma harzianum, Trichoderma reesei and Coriolus versicolor
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DOI：
10.1111/j.1365-2672.2007.03472.x
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发表时间：
2007-12-01
影响因子：
4
通讯作者：
De Leij, F. A. A. M.
中科院分区：
文献类型：
--
作者：
Adams, P.;Lynch, J. M.;De Leij, F. A. A. M.
目的：确定真菌代谢产物在金属解吸中的作用。方法与结果：比较了三种不同真菌对木炭中Zn的解吸效果与反渗透水、0.1% Tween 80溶液和0.1 mol l(-1) CaCl(2)溶液对金属的解吸效果。所有三种真菌滤液解吸Zn的量都是0.1% Tween 80或0.1 mol l(-1) CaCl的三倍(2)。哈茨木霉和花斑木霉的金属螯合剂产生是组成性表达的，而里氏木霉的螯合剂产生是由锌诱导的。锌的存在抑制了紫孢霉产生金属螯合剂。研究发现，只有C. versicolor能产生草酸（一种强金属螯合剂）。所有真菌都导致pH值显著降低，尽管这不足以解释不同真菌滤液对金属解吸的增加。结论：有机酸和蛋白质的金属螯合作用是真菌滤液促进锌解吸的主要机制。本研究的意义和影响：本研究的结果解释了为什么接种了T. harzianum T22的植物比未接种的植物从土壤中吸收更多的金属，而真菌产生的代谢物可以用来从污染的土壤中浸出金属。
Aims: To determine the role of fungal metabolites in the desorption of metals.Methods and Results: Desorption of Zn from charcoal by three different fungi was compared against metal desorption with reverse osmosis water, a 0.1% Tween 80 solution and a 0.1 mol l(-1) CaCl(2) solution. All three fungal filtrates desorbed three times more Zn than either 0.1% Tween 80 or 0.1 mol l(-1) CaCl(2). Metal chelator production in Trichoderma harzianum and Coriolus versicolor was constitutively expressed while chelator production in Trichoderma reesei was induced by Zn. The presence of Zn inhibited the production of metal chelators by C. versicolor. Only C. versicolor was found to produce oxalic acid (a strong metal chelator). All fungi caused a marked decrease in pH, although this was not enough to explain the increased desorption of the metals by the different fungal filtrates.Conclusion: Metal chelation via organic acids and proteins are the main mechanisms by which the fungal filtrates increase zinc desorption.Significance and the Impact of the Study: The results of this study explain why plants inoculated with T. harzianum T22 take up more metal from soil, than noninoculated plants while metabolites produced by fungi could be used for metal leaching from contaminated soils.