Cadmium-responsive thiols in the ectomycorrhizal fungus Paxillus involutus
Cadmium-responsive thiols in the ectomycorrhizal fungus Paxillus involutus
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DOI：
10.1128/aem.70.12.7413-7417.2004
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发表时间：
2004-12-01
影响因子：
4.4
通讯作者：
Leroy, P
中科院分区：
文献类型：
--
作者：
Courbot, M;Diez, L;Leroy, P
外生菌根真菌持续金属耐受性的分子和细胞机制尚不清楚。金属解毒涉及的一些主要机制似乎涉及细胞质中的金属离子与含硫醇化合物（例如谷胱甘肽、植物螯合素或金属硫蛋白）的螯合。我们使用改进的高效液相色谱方法同时测量从半胱氨酸及其衍生物（γ-谷氨酰半胱氨酸、谷胱甘肽）到较高分子量化合物（植物螯合素）的含硫醇化合物。我们发现当外生菌根真菌卷状芽孢杆菌暴露于镉时，谷胱甘肽和γ-谷氨酰胺含量增加。另一种分子量为 3 kDa 的化合物（很可能与金属硫蛋白有关）在暴露于镉的菌丝体中急剧增加。植物螯合素的相对缺乏和假定的金属硫蛋白的存在表明，外生菌根真菌可能使用与其植物宿主不同的方式来耐受重金属，例如镉。
Molecular and cellular mechanisms underlying the sustained metal tolerance of ectomycorrhizal fungi are largely unknown. Some of the main mechanisms involved in metal detoxification appear to involve the chelation of metal ions in the cytosol with thiol-containing compounds, such as glutathione, phytochelatins, or metallothioneins. We used an improved high-performance liquid chromatography method for the simultaneous measurement of thiol-containing compounds from cysteine and its derivatives (gamma-glutamylcysteine, glutathione) to higher-molecular-mass compounds (phytochelatins). We found that glutathione and gamma-glutamyleysteine contents increased when the ectomycorrhizal fungus Paxillus involutus was exposed to cadmium. An additional compound with a 3-kDa molecular mass, most probably related to a metallothionein, increased drastically in mycelia exposed to cadmium. The relative lack of phytochelatins and the presence of a putative metallothionein suggest that ectomycorrhizal fungi may use a different means to tolerate heavy metals, such as Cd, than do their plant hosts.