模拟干湿交替对水稻土古菌群落结构的影响

发布时间：2018-06-01 01:07

  本文选题：高通量测序 + 水稻土　； 参考：《土壤学报》2017年01期

【摘要】：干湿交替是自然界普遍存在的现象,但长期以来由于技术的限制,复杂土壤中微生物对水分变化的响应规律仍不清楚。针对我国江苏常熟湖泊底泥发育的典型水稻土,在室内开展湿润-风干以及风干-湿润各三次循环,每次循环中湿润、风干状态各维持7d,利用微生物核糖体rRNA的通用引物进行PCR扩增,通过高通量测序分析土壤古菌多样性变化,同时结合实时荧光定量PCR技术,在DNA和RNA水平研究古菌数量对干湿交替过程的响应规律。结果表明:水稻土湿润-风干过程中,在DNA水平土壤古菌数量降幅约为149倍~468倍,而在RNA水平降幅最高仅为2.06倍;水稻土风干-湿润过程中,在DNA水平古菌数量增幅在147倍~360倍之间,而在RNA水平增幅最高仅为2.95倍。表明在干湿交替过程中,DNA水平的古菌16S rRNA基因数量变化远高于RNA水平。基于高通量测序多样性的结果表明,在DNA和RNA水平,湿润土壤3次风干、以及风干土壤3次加水湿润7d恢复后,土壤古菌群落结构均发生统计显著性改变。在微生物门、纲、目、科和属的不同分类水平下,水稻土古菌主要包括3、10、13、14、10种不同的类群,在RNA和DNA水平的结果基本一致。干湿交替导致部分古菌类群发生显著变化,其中在微生物分类学目水平发生显著变化的古菌最高达到6种,主要包括产甲烷古菌和氨氧化古菌,如Methanobacteriales、Methanosarcinales、Methanomicrobiales和Nitrososphaerales等。这些研究结果表明,反复的干湿交替并未显著改变水稻土中古菌的主要类群组成,古菌类群的绝对数量和相对丰度发生了一定程度的变化,但这些变化与微生物生理作用的联系仍需进一步研究;风干土壤中古菌RNA序列极可能来自于完整的古菌细胞,暗示了这些古菌细胞能够较好地适应水稻土中水分的剧烈变化,风干状态的土壤在一定程度也可用于土壤古菌群落组成研究。
[Abstract]:Dry-wet alternation is a common phenomenon in nature, but for a long time due to the limitation of technology, the response of microorganisms to water change in complex soil is still unclear. In view of typical paddy soils developed in the sediments of lakes in Changshu, Jiangsu Province, three cycles of wet-air drying and air-dry-wetting were carried out indoors, and each cycle was wetted. The diversity of soil palaeomycetes was analyzed by using universal primers of microbial ribosomal rRNA for 7 days, and the diversity of soil palaeomycetes was analyzed by high-throughput sequencing. Meanwhile, real-time fluorescence quantitative PCR technique was used to analyze the diversity of soil palaeomycetes. The response of ancient bacteria quantity to the alternating process of dry and wet was studied at DNA and RNA levels. The results showed that in the process of wetting and air drying of paddy soil, the decrease of soil paleomycetes at DNA level was about 149 times and 468 times, while that at RNA level was only 2.06 times, and in the process of air-drying and wetting of paddy soil, the decrease of palaeomycetes in paddy soil was about 149-fold and 2.06 times, respectively. The number of palaeomycetes increased by 147-fold in DNA level, but only 2.95 times in RNA level. The results showed that the change of 16s rRNA gene number of Archaea was much higher than that of RNA during dry-wet alternation. Based on the diversity of high throughput sequencing, the results showed that the community structure of soil paleomycetes changed statistically significantly at DNA and RNA levels, 3 times of dry soil and 3 times of dry soil after 7 days of water wetting. Under the different taxonomic levels of phylum, class, order, family and genus, there are mainly 10 different taxa of Paddy soil ancient bacteria, which are the same at RNA and DNA levels. The alternation of dry and wet resulted in significant changes of some paleomycetes, of which the highest was 6 species at the level of microbial taxonomic order, mainly including methanobacterium palaeomycetes and ammonia-oxidizing ancient bacteria, such as Methanobacteriae alesus Methanosarcinales method anomicrobiales and Nitrososphaerales. These results showed that repeated dry-wet alternation did not significantly change the composition of the main taxa in paddy soil, and the absolute number and relative abundance of paleomycetes changed to a certain extent. However, the relationship between these changes and the physiological effects of microbes still needs further study. The RNA sequence of palaeomycetes in air-dried soil is likely to come from intact paleoblast cells, suggesting that these paleomycetes cells can adapt to the severe changes of water in paddy soil. The dry soil can also be used to study the composition of soil paleomycetes community to some extent.
【作者单位】： 中国科学院南京土壤研究所;中国科学院大学;
【基金】：国家重点基础研究发展计划(973计划)项目(2015CB150501)资助~~
【分类号】：S154.3
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本文编号：1962207