Isolation of fungal cellobiohydrolase I genes from sporocarps and forest soils by PCR
Isolation of fungal cellobiohydrolase I genes from sporocarps and forest soils by PCR
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DOI：
10.1128/aem.02893-07
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发表时间：
2008-06-01
影响因子：
4.4
通讯作者：
Zak, Donald R.
中科院分区：
文献类型：
--
作者：
Edwards, Ivan P.;Upchurch, Rima A.;Zak, Donald R.
纤维素是植物生物质的主要组成部分，微生物对纤维素的利用是植物碎屑分解的关键步骤。尽管如此，对土壤中纤维素分解微生物群落的多样性知之甚少。真菌以其纤维素分解活性而闻名，并在陆地生态系统中介导植物碎屑分解的关键功能。我们开发了新的寡核苷酸引物的真菌外切纤维素酶基因（纤维二糖水解酶，cbhI），并使用这些分离不同的cbhI同源物从4种垃圾分解的担子菌真菌（Clitocybe nuda，Clitocybe gibba，Clitopilus pranulus和Chlorophyllum acididites）和2种子囊菌真菌（多形炭角菌和Sarcoseypha ococcuentalis）。cbhI基因家族的证据被发现在四个担子菌物种中的三个。此外，我们从密歇根州下北方的两个高地森林的林地和矿质土壤中分离并克隆了cbh I基因，其中一个主要是橡树（Quercus velutina，Q.另一种以糖枫（Acer saccharum）和美洲椴木（Tilia americana）为主。系统发育分析表明，纤维二糖水解酶基因回收的地板上的两个森林往往集群与炭角菌或在两个身份不明的群体之一，而从土壤中回收的纤维二糖水解酶基因往往集群与木霉，链格孢，散囊菌目，和担子菌序列。扩增参与植物凋落物分解的关键真菌基因的能力具有解开原位纤维素分解真菌群落的身份和动态的潜力。
Cellulose is the major component of plant biomass, and microbial cellulose utilization is a key step in the decomposition of plant detritus. Despite this, little is known about the diversity of cellulolytic microbial communities in soil. Fungi are well known for their cellulolytic activity and mediate key functions during the decomposition of plant detritus in terrestrial ecosystems. We developed new oligonucleotide primers for fungal exocellulase genes (cellobiohydrolase, cbhI) and used these to isolate distinct cbhI homologues from four species of litter-decomposing basidiomycete fungi (Clitocybe nuda, Clitocybe gibba, Clitopilus pranulus, and Chlorophyllum molybdites) and two species of ascomycete fungi (Xylaria polymorpha and Sarcoseypha occidentalis). Evidence for cbhI gene families was found in three of the four basidiomycete species. Additionally, we isolated and cloned cbhI genes from the forest floor and mineral soil of two upland forests in northern lower Michigan, one dominated by oak (Quercus velutina, Q. alba) and the other dominated by sugar maple (Acer saccharum) and American basswood (Tilia americana). Phylogenetic analysis demonstrated that cellobiohydrolase genes recovered from the floor of both forests tended to cluster with Xylaria or in one of two unidentified groups, whereas cellobiohydrolase genes recovered from soil tended to cluster with Trichoderma, Alternaria, Eurotiales, and basidiomycete sequences. The ability to amplify a key fungal gene involved in plant litter decomposition has the potential to unlock the identity and dynamics of the cellulolytic fungal community in situ.