PGPR菌剂对植烟土壤理化性状及phoD基因群落结构的影响

为探明PGPR菌剂对土壤磷素循环的微生物调控机制，以凉山州会理市的植烟田为研究对象，采集烤烟成熟期耕层土壤，通过化学分析和高通量测序技术，对细菌型、放线菌型和真菌型3种PGPR菌剂处理土壤的理化性质、磷酸酶活性及phoD基因群落组成进行了分析。结果表明，与常规施肥相比，施用3种PGPR菌剂均能显著提高土壤有机碳、全氮、有效磷和速效钾含量，放线菌型PGPR菌剂能显著提升土壤的磷酸酶活性。PGPR菌剂能提高植烟土壤phoD基因群落的多样性，门水平优势菌群为放线菌门（Actinobacteria）、变形菌门（Proteobacteria）和蓝菌门（Cyanobacteria）等，属水平优势菌属为链霉菌属（Streptomyces）、无枝酸菌属（Amycolatopsis）和慢生根瘤菌属（Bradyrhizobium）等。冗余分析显示，速效钾、pH、速效磷等环境因子是影响植烟土壤phoD基因群落结构的主要因子。综上所述，PGPR菌剂能显著改善植烟土壤养分状况，提高土壤磷酸酶活性，改变烤烟耕层phoD基因群落结构。

Effects of PGPR Inoculants on Physical and Chemical Properties of Tobacco Planting Soil and Composition of Bacterial Community Containing phoD

In order to explore the microbial regulation mechanism of PGPR on soil phosphorus cycle, tobacco planting fields treated with bacterial, fungal and actinomycete PGPR inoculum respectively in Huili City, Liangshan Prefecture, the cultivated soil in the mature period of flue-cured tobacco was collected to conduct. Chemical analysis and high-throughput sequencing, and soil physical and chemical properties, phosphatase activity, and the composition and diversity of bacterial community containing phoD gene were analyzed. The results showed that the application of three PGPR agents could significantly increase the content of soil organic carbon, total nitrogen, available phosphorus and available potassium, among which the actinomycete PGPR agent could significantly increase the phosphatase activity of soil; PGPR could also improve the diversity of phoD community in tobacco planting soil. The dominant bacteria at the phylum level were Actinobacteria, Proteobactera and Cyanobacteria, and the dominant bacteria at the genus level were Streptomyces, Amycolatopsis and Bradyrhizobium; Redundancy analysis showed that available potassium, pH, available phosphorus and other environmental factors were the main factors affecting the community structure of bacteria containing phoD gene in tobacco planting soil. To sum up, PGPR can significantly improve the nutrient status of tobacco planting soil, increase soil phosphatase activity, and change the structure of phoD gene community in the cultivated layer of flue-cured tobacco.