Abstract:

To Study the effects of organic fertilizer and calcium fertilizer on the microbial community structure and function in the peanut rhizosphere of saline-alkali soils， the peanut rhizosphere soils with different salinity contents （slightly and severely saline-alkali soils） were performed experiments with control （no fertilization， CK）， calcium fertilizer （C）， organic fertilizer （M） and organic fertilizer+calcium fertilizer （CM）. Then the peanut rhizosphere soils were used to extract DNA for constructing bacterial 16S rRNA gene library， and high-throughput sequencing was performed for sequencing and bioinformatics analysis. The results showed that the application of organic fertilizer， calcium fertilizer and the combination of organic fertilizer and calcium fertilizer had significant effects on the diversity and richness of rhizosphere microbes in slightly saline-alkali soil， but had no significant effects in severely saline-alkali soil. PCoA analysis showed that the OTUs diversity was closely related to the salinity contents of soil， and the structure of the rhizosphere microbial community treated with calcium fertilizer was significantly different from those of other treatments. The rhizosphere microbial structures of the two kinds of coastal saline soils were affected by organic fertilizer， calcium fertilizer and the combination of organic fertilizer and calcium fertilizer. The dominant bacterial communities of different treatments were similar， while the relative abundances of dominant bacterial communities were difference in different treatments. On the order and family levels， OTUs of new species accounted for 76.3%~82.5% of the total bacteria， which indicated the rhizosphere in the coastal saline soil of the Yellow River Delta contained a large number of new microbial species resources. The analysis of 16S rRNA function prediction indicated that the application of organic fertilizer， calcium fertilizer and the combination of organic fertilizer and calcium fertilizer increased the abundances of genes on carbohydrate transport and metabolism， amino acid metabolism， energy production and conversion， metabolism of cofactors and vitamins， nucleotide metabolism， translation and membrane transport. In conclusion， the application of calcium fertilizer and organic fertilizer could be beneficial to improve the rhizosphere microecological environment of saline-alkali soil and enhance plant stress tolerance.

Key words: saline-alkali soil, peanut rhizosphere, microbial community diversity, organic fertilizer, calcium fertilizer, 16S rRNA

摘要：

为研究有机肥和钙肥对盐碱地花生根际微生物群落结构和功能的影响，以不施肥为对照（CK）、设置施用钙肥（C）、有机肥（M）和有机肥+钙肥（CM）处理，通过构建细菌16S rRNA基因文库和高通量测序技术对不同处理下花生根际微生物进行测序。结果表明，施用有机肥、钙肥和有机肥钙肥配施均显著影响较轻度盐碱土壤花生根际微生物的多样性和丰富度，而对较重度盐碱土花生根际细菌的多样性和丰富度无显著影响。PCoA分析表明，样本OTUs多样性与土壤盐碱程度关系密切，施用钙肥处理花生根际微生物的菌群结构与其他处理间存在较大差异。两种滨海盐碱土花生根际微生物的种群结构均受施用有机肥、钙肥及其配施的影响，不同处理根际微生物均具有相同的优势菌群，但各优势菌群的相对丰度存在较大差异。在目和科水平上，有占总细菌76.3%～82.5%的新种OTUs未能注释，说明黄河三角洲滨海盐碱土花生根际蕴含大量微生物新种资源。16S rRNA功能预测分析表明，施用钙肥和有机肥处理均可显著提高2种土壤花生根际微生物碳水化合物代谢、氨基酸代谢、能量代谢、辅助因子和维生素的代谢、核苷酸代谢、翻译和膜运输等相关功能基因丰度。由此可见，施用钙肥和有机肥有利于改良盐碱土壤根际微生态环境，提高植物胁迫耐受性。

关键词: 盐碱土, 花生根际, 微生物菌群多样性, 有机肥, 钙肥, 16S rRNA