Lignin and soluble phenolic degradation by ectomycorrhizal and ericoid mycorrhizal fungi
Lignin and soluble phenolic degradation by ectomycorrhizal and ericoid mycorrhizal fungi
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DOI：
10.1017/s0953756297004140
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发表时间：
1997-11-01
影响因子：
--
通讯作者：
Read, DJ
中科院分区：
文献类型：
--
作者：
Bending, GD;Read, DJ
石南草原和温带森林生态系统的有机土壤层具有丰富的酚类物质的特征，这对微生物群的有机氮有效性构成了障碍。比较了外生菌根（ECM）、ericoid菌根和木材腐养真菌对不溶性酚类木质素和可溶性酚类模型化合物的降解能力，这些模型化合物分别对有机氮有效性提供物理和化学屏障。降解木质素的能力与可溶性酚类之间没有明确的关系。推测分析表明，相对于木材分解真菌，大多数菌根真菌对这些化合物的降解能力较低。总的来说，类根菌根真菌比大多数ECM物种具有更强的酚降解能力，其降解能力与酚氧化酶的产生有关。在任何情况下，菌根真菌对木质素或可溶性酚的降解，或酚氧化酶的产生，都没有木材分解真菌那么大。对ericoid内生菌Hymenoscyphus ericae而言，苯酚氧化与细胞外o-多酚氧化酶（酪氨酸酶）的产生有关，该酶在pH为5-5.5和温度为30℃时表现出最佳活性。
The organic soil horizons of heathland and temperate forest ecosystems are characteristically rich in phenolics, which present barriers to organic N availability to the microflora. The abilities of ectomycorrhizal (ECM), ericoid mycorrhizal and wood decomposing saprotrophic fungi to degrade model compounds representing the insoluble phenolic lignin, and soluble phenolics, which provide physical and chemical barriers respectively to organic N availability, were compared. No clear relationship was found between ability to degrade lignin and soluble phenolics. The presumptive assays indicated that most mycorrhizal fungi have only low abilities to degrade these compounds relative to the wood decomposing fungi. In general, ericoid mycorrhizal fungi were capable of greater phenolic degradation than most ECM species, and degradative ability was associated with production of phenol-oxidizing enzymes. In no case was presumptive degradation of lignin or soluble phenolic, or production of phenol-oxidizing enzymes by mycorrhizal fungi as great as that of the wood decomposing fungi. in the case of the ericoid endophyte Hymenoscyphus ericae, phenol-oxidation was associated with production of an extracellular o-polyphenol oxidase (tyrosinase) which showed optimal activity at a pH of 5-5.5 and temperature of 30 degrees C. The ecological significance of the results is discussed.