Metagenomic analyses reveal no differences in genes involved in cellulose degradation under different tillage treatments
Metagenomic analyses reveal no differences in genes involved in cellulose degradation under different tillage treatments
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DOI：
10.1093/femsec/fiv069
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发表时间：
2015-07-01
影响因子：
4.2
通讯作者：
Schloter, Michael
中科院分区：
文献类型：
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作者：
de Vries, Maria;Schoeler, Anne;Schloter, Michael
加入植物凋落物是一种常见的农业做法，以增加土壤中的养分有效性，并在很大程度上依赖于纤维素降解微生物的活动。在这里，我们在一个长期的农业试验中解决了不同耕作处理如何影响土壤微生物群落及其纤维素降解潜力的问题。为了确定微生物分类和功能的潜在差异，我们生成了常规（CT）和减少（RT）耕作处理的表土样品的六个土壤宏基因组，它们在潜在的细胞外纤维素水解活性以及微生物生物量方面存在差异。宏基因组数据的分类分析显示，RT和CT之间差异不大，变形菌门和放线菌门占主导地位，而真核菌门不普遍。纤维素水解酶预测表明，土壤中最丰富的是糖苷水解酶家族1、3和94，辅助活性家族8和碳水化合物结合模块2。这些主要被标注为变形菌门、放线菌门和拟杆菌门。这些结果表明，在RT土壤中观察到的较高的纤维素水解活性可以通过较高的微生物生物量或表达水平的变化来解释，而不是土壤微生物组的变化。总的来说，本研究揭示了不同耕作方式下土壤微生物群落和纤维素水解基因组成的稳定性。
Incorporation of plant litter is a frequent agricultural practice to increase nutrient availability in soil, and relies heavily on the activity of cellulose-degrading microorganisms. Here we address the question of how different tillage treatments affect soil microbial communities and their cellulose-degrading potential in a long-term agricultural experiment. To identify potential differences in microbial taxonomy and functionality, we generated six soil metagenomes of conventional (CT) and reduced (RT) tillage-treated topsoil samples, which differed in their potential extracellular cellulolytic activity as well as their microbial biomass. Taxonomic analysis of metagenomic data revealed few differences between RT and CT, and a dominance of Proteobacteria and Actinobacteria, whereas eukaryotic phyla were not prevalent. Prediction of cellulolytic enzymes revealed glycoside hydrolase families 1, 3 and 94, auxiliary activity family 8 and carbohydrate-binding module 2 as the most abundant in soil. These were annotated mainly to the phyla of Proteobacteria, Actinobacteria and Bacteroidetes. These results suggest that the observed higher cellulolytic activity in RT soils can be explained by a higher microbial biomass or changed expression levels but not by shifts in the soil microbiome. Overall, this study reveals the stability of soil microbial communities and cellulolytic gene composition under the investigated tillage treatments.