腾格里沙漠东南缘藓结皮微生物组基因多样性及功能

本研究对腾格里沙漠东南缘沙坡头地区藓结皮土壤样品进行了宏基因组测序, 以揭示该地区藓结皮土壤中参与固碳、固氮等生态功能的微生物基因及其代谢通路。结果表明, 藓结皮土壤中细菌域微生物最多, 其次为古生菌域和真核生物域。在细菌域中, 放线菌门(Actinobacteria)数量最多, 其次是变形菌门(Proteobacteria)和蓝细菌门(Cyanobacteria)。基于eggNOG和KEGG数据库对构建的非冗余基因集进行功能预测, 藓结皮土壤中微生物基因多样性和代谢路径多样性高。藓结皮土壤中与固氮相关的代谢通路丰度低可能是藓结皮固氮量微弱的根本原因, 造成利用大气中氮气合成氨的生态功能减弱。而藓结皮已经形成的氮库主要通过硝酸盐还原途径将硝酸盐还原成铵盐, 可能用于藓结皮微生物组自身的氨基酸合成, 也可能为藓类植物的生长提供有效氮源。

Gene diversity and its function in the soil microbiome for moss crusts found southeast of the Tengger Desert

Metagenomics sequencing was used to reveal the diversity of genes and their metabolic pathways involved in carbon sequestration and nitrogen fixation in moss crusts in Shapotou region, located southeast of the Tengger Desert. Results showed that the microbial community related to the bacteria domain in the moss crust was the largest, followed by archaea and eukaryota. In the bacterial domain, the most abundant phyla was the Actinobacteria, followed by the Proteobacteria and Cyanobacteria. Based on the functional classification of eggNOG and KEGG databases for the functional prediction of non-redundant gene catalog, the diversity of gene and metabolic pathways in the moss crust soil was high. Low nitrogen fixation was found in the moss crust as there are less metabolic pathways related to nitrogen-fixation, weakening the ecological function of ammonia synthesis from atmosphere nitrogen. The nitrate from the nitrogen pool formed by moss crust were mainly reduced to ammonium salt by nitrate reduction pathway, which may be used for the synthesis of amino acids for microbiome in the moss crust, and may also provide an effective nitrogen source for the growth of mosses.