Differences in Ureolytic Bacterial Composition between the Rumen Digesta and Rumen Wall Based on ureC Gene Classification.
Differences in Ureolytic Bacterial Composition between the Rumen Digesta and Rumen Wall Based on ureC Gene Classification.
复制标题
基于ureC基因分类的瘤胃消化液和瘤胃壁尿素分解细菌组成差异
DOI：
10.3389/fmicb.2017.00385
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发表时间：
2017
影响因子：
5.2
通讯作者：
Wang J
中科院分区：
文献类型：
--
作者：
Jin D;Zhao S;Zheng N;Bu D;Beckers Y;Denman SE;McSweeney CS;Wang J
尿素分解菌是瘤胃中产生尿素酶的关键生物，其催化尿素分解为氨以合成微生物蛋白。然而，目前对瘤胃尿素分解微生物的多样性和分布知之甚少。尿素酶基因（ureC）已成为分析各种环境中尿素降解微生物的首选靶基因。本研究利用高通量测序技术对奶牛瘤胃中尿素分解菌的优势尿素酶基因进行了研究。将6头患有瘤胃瘘管的奶牛进行两阶段交叉试验。对照组（n = 3）饲喂不含尿素的全混合日粮，治疗组（n = 3）饲喂日粮加180 g尿素/头奶牛每天在三个不同的时间。收集来自液体和固体瘤胃和瘤胃壁部分的瘤胃细菌样品用于ureC基因扩增和使用Miseq测序。与固体粘附细菌（SAB）和液体相关细菌（LAB）相比，壁粘附细菌（WAB）具有独特的尿素分解细菌谱，但超过55%的ureC序列不与任何已知的分类学分配的尿素酶基因相关联。ureC基因的多样性分析表明，瘤胃WAB的Shannon指数和Chao 1指数显著低于SAB和LAB（P < 0.01）。ureC基因在Methylococcaceae、Clostridiaceae、Paenibacillaceae、Helicobacteraceae和Methylophilaceae中的分布最丰富。与瘤胃LAB和SAB相比，WAB中Methylophilus和Marinophilus属OTU的相对丰度显著（P < 0.05）。补充尿素并没有改变检测到的尿素分解细菌的组成。这项研究已经确定了显着的群体的尿素分解WAB代表尚未认识到或以前在瘤胃中研究的属。奶牛瘤胃ureC基因的分类学分类表明，大多数尿素分解细菌尚未被鉴定。本研究扩大了我们对与瘤胃尿素分解菌群相关的ureC基因信息的了解，并为获得瘤胃尿素分解菌调节尿素水解的调控靶点提供了基础。
Ureolytic bacteria are key organisms in the rumen producing urease enzymes to catalyze the breakdown of urea to ammonia for the synthesis of microbial protein. However, little is known about the diversity and distribution of rumen ureolytic microorganisms. The urease gene (ureC) has been the target gene of choice for analysis of the urea-degrading microorganisms in various environments. In this study, we investigated the predominant ureC genes of the ureolytic bacteria in the rumen of dairy cows using high-throughput sequencing. Six dairy cows with rumen fistulas were assigned to a two-period cross-over trial. A control group (n = 3) were fed a total mixed ration without urea and the treatment group (n = 3) were fed rations plus 180 g urea per cow per day at three separate times. Rumen bacterial samples from liquid and solid digesta and rumen wall fractions were collected for ureC gene amplification and sequencing using Miseq. The wall-adherent bacteria (WAB) had a distinct ureolytic bacterial profile compared to the solid-adherent bacteria (SAB) and liquid-associated bacteria (LAB) but more than 55% of the ureC sequences did not affiliate with any known taxonomically assigned urease genes. Diversity analysis of the ureC genes showed that the Shannon and Chao1 indices for the rumen WAB was lower than those observed for the SAB and LAB (P < 0.01). The most abundant ureC genes were affiliated with Methylococcaceae, Clostridiaceae, Paenibacillaceae, Helicobacteraceae, and Methylophilaceae families. Compared with the rumen LAB and SAB, relative abundance of the OTUs affiliated with Methylophilus and Marinobacter genera were significantly higher (P < 0.05) in the WAB. Supplementation with urea did not alter the composition of the detected ureolytic bacteria. This study has identified significant populations of ureolytic WAB representing genera that have not been recognized or studied previously in the rumen. The taxonomic classification of rumen ureC genes in the dairy cow indicates that the majority of ureolytic bacteria are yet to be identified. This survey has expanded our knowledge of ureC gene information relating to the rumen ureolytic microbial community, and provides a basis for obtaining regulatory targets of ureolytic bacteria to moderate urea hydrolysis in the rumen.