施用Streptomyces alfalfae XY25~T对根肿病土壤性质及微生物群落的影响

Effect of Streptomyces alfalfae XY25~T application on physicochemical properties and microflora in clubroot-diseased soil

[背景]根肿病是一种世界性土传病害,鄂西高山不少田块大白菜发病率高达60%,严重制约了当地蔬菜产业的发展。[目的]揭示Streptomyces alfalfae XY25^T防治过程中土壤理化性质的变化规律及其对根际土壤微生物群落的影响。[方法]大白菜幼苗移栽至病区土壤盆栽中,处理组施用S.alfalfae XY25^T,并设置对照组。移栽后第7、14、21、28、35天采集土壤样本,测定根际土壤酶活力和土壤肥力;第35天提取土壤DNA,采用高通量测序技术,结合生物信息学分析,解析大白菜根际土壤细菌和真菌群落结构组成及多样性。[结果]施用S.alfalfae XY25^T提高了土壤pH值、有机质、碱解氮、速效钾和速效磷的含量,比例分别为10.0%、13.7%、12.0%、41.1%和8.71%;增加了蔗糖酶、脲酶、过氧化氢酶和碱性磷酸酶活力,比例分别是333%、204%、36.1%和142%;提高了Ascomycota、Zygomycyota及Actinobacteria菌门的相对丰度,比例分别为54.1%、22.8%和10.7%;降低了Acidobacteria的相对丰度,比例是7.59%;提高了Penicillium、Mortierella、Mucor和Streptomyces等菌属的相对丰度,比例分别为25.5%、14.6%、8.20%和7.24%。[结论]施用S.alfalfae XY25^T改善了土壤理化性质,改变了根际土壤微生物群落结构和多样性。

[Background] Clubroot, one of the most important soil-borne diseases in the world, is posing a serious threat to the vegetable farming in the Northwest of Hubei, leading to an incidence rate as high as 60% for Chinese cabbage in many fields. [Objective] To study the effects of Streptomyces alfalfae XY25^T application on physicochemical properties and microbial community in rhizosphere soil. [Methods] Pot experiments of Chinese cabbage were done in greenhouse, using the diseased soil with S. alfalfae XY25^T application as the treatment group and the diseased soil without S. alfalfae XY25^T application as the control group. On day 7, 14, 21, 28 and 35 after seedling transplantation, soil samples were collected for analysis of the variations in the enzyme activity and nutrient content in the rhizosphere soil. On day 35, the total DNA was extracted from soil samples. The composition and diversity of bacterial and fungal communities were investigated by using high-throughput sequencing technology combined with bioinformatics analysis. [Results] Compared with the control, the application of S. alfalfae XY25^T increased pH value, content of organic matter, alkali-hydrolysable nitrogen, available kalium, and available phosphorus in the soil by 10.0%, 13.7%, 12.0%, 41.1%, and 8.71%, respectively. It also increased the soil enzyme activity, with an increase of 333%, 204%, and 36.1%, 142% in the soil invertase activity, urease activity, catalase activity, and alkaline phosphatase activity. Moreover, S. alfalfae XY25^T application improved the soil microbial community structure and diversity, leading to an increase of 54.1%, 22.8%, and 10.7% in the relative abundance of Ascomycota, Zygomycota, and Actinobacteria, in contrast to a 7.59% decrease in the relative abundance of Acidobacteria. Furthermore, S. alfalfae XY25^T application also increased the relative abundance of Penicillium, Mortierella, Mucor, and Streptomyces by 25.5%, 14.6%, 8.20%, and 7.24%, respectively. [Conclusion] The application of S. alfalfae XY25^T not only improved the soil quality but also significantly altered the microbial community structure a nd diversity in rhizosphere soil.