大庆盐碱地九种植物根际土壤微生物群落结构及功能多样性

盐碱土是陆地表面生态脆弱区域。它与荒漠化过程相伴而生,不但造成了资源的破坏、农业生产的巨大损失,而且还对生物圈和生态环境构成威胁。研究盐碱地植物根际土壤微生物群落的多样性,对于盐碱土壤的植被恢复和生态重建具有重要意义。运用PCR-DGGE技术和Biolog微平板法,对大庆盐碱地9种不同植物根际土壤微生物结构和功能的多样性进行了分析。结果表明,不同植物根际土壤微生物组成不同,同一科的植物具有相似的微生物组成。对11个克隆进行了序列测定,发现这一地区植物根际优势微生物菌群为变形菌门(Proteobacteria)和酸杆菌门(Acidobacteria)。利用Biolog微平板法分析了微生物群落功能多样性。结果表明,不同植物根际土壤细菌群落对底物碳源的代谢特征存在着一定的差异,其中豆科的野大豆根际土壤细菌对底物碳源的代谢能力最强。

Structural and functional diversity of rhizosphere microbial community of nine plant species in the Daqing Saline-alkali soil region

Saline-alkali soils are particularly ecologically fragile. They generally form following desertification, which destroys natural resources and causes heavy losses to agriculture production. Daqing, a city in the northern province of Heilongjiang, is renowned for its vast oil reserves. Exploitation of these reserves has led to soil contamination by petroleum-derived products, and this is becoming serious ecological problem in this city. Saline-alkali soil is another factor that contributes to rendering most of its agricultural land unusable. In recent years, bioremediation, especially microbial remediation, has been a global focus of research. It is more effective, safer, and more environmentally friendly than other remediation strategies, such as chemical or physical methods. The rhizosphere-the layer of soil influenced by plant roots-is much richer in microbial diversity than the surrounding bulk soil. Exploring the diversity of plant rhizosphere microbial communities in Saline-alkali soils can therefore provide a scientific basis for vegetation restoration and ecological reconstruction in this region. This study focused on plant rhizosphere microbial communities in Saline-alkali soils in the Daqing region. Using Biolog EcoPlate methods, denaturing gradient gel electrophoresis (DGGE) analysis, and subsequent DNA sequencing, we investigated the structural and functional diversity of rhizosphere microbial communities associated with nine plant species in Daqing Saline-alkali soils. The structure of the rhizosphere microbial community associated with each plant species was analyzed by DGGE. Plants in the same family tended to have similar rhizosphere microbial community compositions. Rhizosphere bacteria were dominated by Proteobacteria andAcidobacteria,based on the analysis of 16S rRNA. Pairwise rhizosphere population genetic distances between plant species were calculated using Quantity One software (Bio-Rad Laboratories). In combination with clustering analysis based on the unweighted pair group method with arithmetic mean, it was confirmed that rhizosphere microbial communities reflect relationships among the plant species tested. Biolog EcoPlate was used to investigate the functional diversity of rhizosphere microbial communities. This method is more sensitive to changes in the environment than the other methods such as phospholipid fatty-acid analysis. Changes in functional diversity patterns can be statistically analyzed via principle component analysis of average well color development data. The capacity of rhizobacteria to metabolize carbon sources was higher in communities associated with wild soybean than in other plant species tested. The data also suggest that rhizobacteria from different plant species have distinct carbon metabolism characteristics. While there are limitations in the methods used in this study, they nevertheless provided useful information. Metagenomics-the study of genetic material recovered directly from environmental samples-is becoming increasingly popular as a research tool. It provides a powerful lens for viewing the microbial world that has the potential to revolutionize the understanding of the entire living world. The results of this study offer advanced insights in the field of microbial ecology and provide a theoretical basis for future practical applications.