“使它隆”对玉米根部不同微生环境细菌群落多样性的影响

Effects of “starane” on the diversity of bacterial communities in different micro-environment of maize roots

摘要:

[目的]研究除草剂“使它隆”施用后对玉米根部不同微生环境细菌群落结构和多样性的影响。[方法]利用Illumina Miseq高通量测序技术，对玉米根系内生菌、根际和非根际土壤细菌16S rRNA的V4–V5可变区序列进行测定，分析不同生长期喷施除草剂使它隆对玉米土壤细菌及根系内生菌群落结构和多样性的影响。[结果]本研究15个样品共得到544393条有效序列，333565条优质序列。多样本共有OTU分析表明，非根际和根际土壤的群落结构更为相似，在一定程度上说明玉米根部相关细菌的定殖具有选择性并且是从根际到根系逐步专一化。丰度等级曲线和Alpha多样性结果显示非根际和根际土壤群落的丰富度和均匀度较高，而玉米根系内生菌群落的丰富度和均匀度都比较低，且成熟期玉米根系内生菌群落的丰富度在施用除草剂使它隆后下降比较剧烈。群落组成分析发现，使它隆除草后，玉米根部相关细菌各时期在门及属水平上的分布都发生了较大变化。菌群代谢功能预测结果表明玉米生长从苗期到成熟期，微生物的生长压力逐渐加大，需要消耗更多的能量用于新陈代谢和环境适应。[结论]施用除草剂使它隆后会降低玉米根部土壤细菌群落的多样性，使它隆对成熟期玉米根系内生菌群落影响最为显著。

关键词:高通量测序;玉米;使它隆;细菌多样性

Abstract:

[Objective] The purpose of this research is to study the effects of herbicide "starane" on the structure and diversity of bacterial communities in different micro-environments. [Methods] We used the high-throughput sequencing technique Illumina Miseq to determine the V4-V5 variable region sequence of 16S rRNA in endophytic, rhizosphere and non-rhizosphere soils of maize roots. The herbicides were sprayed in different growth stages, and we researched the herbicide effect on the structure and diversity of maize root endophytes as well as soil bacteria. [Results] We obtained a total of 544393 effective sequences and 333565 high-quality sequences from 15 samples. The multi-sample OTU analysis showed that the community structure of non-rhizosphere soil and rhizosphere soil was similar, which indicated that the colonization of maize-related bacteria was selective and the gradual specialization from rhizosphere to root. The results of rank abundance curve and Alpha diversity showed that the richness and uniformity of non-rhizosphere and rhizosphere soil were higher, while the richness and uniformity of endophytic community in maize roots of mature stage were lower. The abundance of endophytic community in maize roots was significantly reduced by the application of herbicides. The composition analysis of the community showed that the distribution of bacteria in the maize roots was with a great change at both the Phylum and Genus level. The prediction of metabolic function of the flora indicated that the growth pressure of the microorganisms was gradually increased from the seeding stage to the mature stage of the corn, which required more energy for bacterial metabolism and environmental adaptation. [Conclusion] The application of herbicide "starane" can reduce the diversity of bacterial community in the roots of maize, and the effect on the endophytic community of maize roots is more obvious.

Key words:high-throughput sequencing;maize;starane;bacterial diversity