枯草芽胞杆菌菌肥对有机冬瓜根区土壤微生态的影响

Effect of Bacillus subtilis microbial fertilizer on root-zone soil microbial ecology of organic Chinese watermelon

摘要:

【背景】微生物肥料已广泛应用于我国有机作物的种植，其对有机种植土壤微生态的影响尚需科学评测。【目的】高通量测序技术可用于精确分析土壤微生物群落，从细菌、真菌群落结构和多样性的角度阐释枯草芽胞杆菌菌肥对有机农田根区土壤微生物群落的影响。【方法】在有机农田轮作种植条件下，施用枯草芽胞杆菌菌肥后提取冬瓜根区土壤基因组DNA，通过PCR扩增建立文库，利用Illumina MiSeq高通量测序技术，并结合相关生物信息学方法分析土壤细菌16S rRNA基因V3?V4区和真菌ITS1区的多样性指数及群落结构；测定根区土壤化学性质及酶活性，分析有机冬瓜果实品质，并作相关分析。【结果】从6个有机冬瓜根区土壤样本中获得14 199个细菌操作分类单元(OTU)和3 378个真菌OTU，细菌和真菌文库测序覆盖率分别在98%、99%以上。枯草芽胞杆菌菌肥会在一定程度上提高土壤细菌种群多样性而降低真菌种群多样性，丰富了细菌群落结构，但显著降低了真菌群落丰富度(P<0.05)；并减少了根区土壤特有细菌和真菌物种。变形菌门、厚壁菌门和放线菌门是优势细菌，子囊菌门是优势真菌；枯草芽胞杆菌菌肥会提高绿弯菌门和子囊菌门的相对丰度，比例分别为46.23%、10.01%；降低变形菌门和担子菌门的相对丰度，比例分别为11.14%、74.72%。枯草芽胞杆菌菌肥显著降低了土壤pH，显著提高了有机冬瓜果实总氨基酸、可溶性固形物等营养成分含量(P<0.05)。【结论】施用枯草芽胞杆菌菌肥改变有机冬瓜根区土壤细菌和真菌的丰富度和多样性，降低了土壤pH，提高了有机冬瓜果实品质。

Abstract:

[Background] Microbial fertilizers have been widely used in the cultivation of organic crops in China, and their effects on the micro-ecology in soils of organic farm still needs scientific evaluation. [Objective] The high-throughput sequencing technology can be used to analyze soil microbial community accurately. We explained effects of Bacillus subtilis microbial fertilizer on organic farm root-zone soil bacterial and fungal community in the view of structure and diversity. [Methods] Under organic and rotate farming conditions, soil genomic DNA was extracted after application of Bacillus subtilis microbial fertilizer. And PCR amplification was made to establish libraries. Then, the 16S rRNA genes V3?V4 regions of soil bacterium and fungal ITS1 regions were sequenced by Illumina high-throughput sequencing technology on MiSeq platform, and related biological analysis was conducted to explain the changes of soil bacterial and fungal diversities and structures. In addition, soil chemical properties and enzyme activities, nutritional quality of organic Chinese watermelon were determined. [Results] A total of 14 199 bacterial operational taxonomic units (OTUs) and 3 378 fungal OTUs were obtained from 6 organic Chinese watermelon root-zone soil samples. The sequencing coverage of bacterial and fungal libraries were above 98% and 99%, respectively. Bacillus subtilis microbial fertilizer would increase the soil bacterial diversity while reduce the fungal diversity to a certain degree, and increased the abundance of bacteria, but it reduced the abundance of fungi significantly (P<0.05), and reduced the number of bacterial and fungal unique OTU. Proteobacteria, Firmicutes and Actinobacteria were the dominant bacteria, and Ascomycota was dominant fungi. It increased the relative abundance of Chloroflexi and Ascomycota by 46.23% and 10.01%, respectively. And, it reduced the relative abundance of Proteobacteria and Basidiomycota by 11.14% and 74.72%, respectively. It significantly reduced the pH of soil (P<0.05). Wherein, it significantly increased the content of total amino acids and soluble solid in organic Chinese watermelon (P<0.05). [Conclusion] The abundance and diversity of soil bacteria and fungi were changed with Bacillus subtilis microbial fertilizer applied. And soil pH was reduced, nutritional quality of organic Chinese watermelon was increased also.