【作者】 王岩；

【导师】 杨洪岩；

【作者基本信息】 东北林业大学 ， 生物学， 2022， 硕士

【摘要】 人参是我国传统名贵中药材,具有增强器官功能、抑制炎症、预防肿瘤及抗病毒等多重功能。中国作为世界上最早开展人参栽培的国家,现今栽培面积和产量位居世界首位,其作用及经济地位不容忽视。由于伐林栽参破坏林区植被系统,严重危及林区生态安全,已被严令禁止,人参种植已向农田栽参模式转移。农田土壤病害严重、有益微生物少、养分失衡等诸多因素限制着人参产业的进一步发展。如何调控土壤微生态系统、促进微生物群落正向演替、有效防治土传病害是亟待解决的科学问题。本研究首先分析人参不同栽培土壤的理化及微生物学分布特征,明确被孢霉在土壤中的分布规律以及与土壤健康的相关性;进一步,为明确被孢霉对土传病害的防治潜力,以分离获得的高山被孢霉为代表菌株,采用平板培养与盆栽接种试验对被孢霉与根腐病原真菌尖孢镰刀菌及人参植物的相互作用进行了解析。获得的结果如下:（1）通过分析林地、农田和4年参地土壤养分发现,不同类型土壤中速效氮（NO₃^--N和NH₄⁺-N）、有效磷、全氮、全磷和有机质含量均存在显著差异;高通量测序显示,Alpha多样性表明林地土壤中细菌和真菌的丰富度和多样性显著高于4年参地土壤;被孢霉在不同类型土壤中均占有较高的比例,且在林地土壤中被孢霉的相对丰度显著高于农田和4年参地土壤,暗示土壤被孢霉的丰度可能成为土壤健康的指示因子。（2）从人参根际分离出一株高山被孢霉,分析其与土壤微生物的相互作用及促生潜力。结果显示,高山被孢霉的菌丝生长受到土壤中芽孢杆菌、链霉菌、短杆菌、木霉、青霉等益生菌和枝孢霉、曲霉等潜在病原菌的抑制;但与人参根腐病病原菌尖孢镰刀菌无明显相互作用;高山被孢霉具有生产吲哚乙酸的潜力,在含有3 mM色氨酸的PDA培养基中培养4 d时吲哚乙酸产量最高可达141.37 mg/L;培养5 d后,蛋白酶活性为5.5 U/mL;未发现其具有产铁载体、溶磷、淀粉酶、纤维素酶、果胶酶和木聚糖酶活性。（3）为明确高山被孢霉接种对人参植株抗病性的影响,设置单接种高山被孢霉（MA）、单接种尖孢镰刀菌（FO）和两者共同接种（MA＿FO）的处理进行人参盆栽试验。结果表明,在人参根际接种高山被孢霉可显著减轻人参植株感染根腐病的症状,高山被孢霉与尖孢镰刀菌共接种可使人参植株中潜在病原菌的相对丰度降低,有益微生物的相对丰度增加,并可帮助人参根部构建更加稳定的微生物网络,以促进人参植株生长。（4）人参根际土壤系统解析结果表明,单独接种高山被孢霉可显著提高土壤中铵态氮、有效磷和有效钾的含量以及脲酶、蔗糖酶和酸性磷酸酶的活性;db-RDA分析表明,土壤铵态氮和有效磷含量分别是对根际细菌和真菌群落差异影响最大的因素;线性回归分析表明,高山被孢霉可能通过提高土壤蔗糖酶活性来抵御尖孢镰刀菌的入侵;结合对土壤微生物组成和组间差异分析表明,高山被孢霉接种可显著降低土壤中尖孢镰刀菌的相对丰度,有助于土壤理化及微生物群落的正向演替。更多还原

【Abstract】 Ginseng is a precious traditional Chinese medicine with multiple functions,such as enhancing organ functioning,inhibiting inflammation,preventing tumor and antiviral.As the first country to develop ginseng cultivation in the world,the cultivated area and yield of ginseng in China now ranks first.Therefore,ginseng’s role and economic status cannot be ignored.Because of the destruction of forest vegetation system and hazards forest ecological security,planted ginseng by deforestation has been strictly prohibited.Planting ginseng in farmland has been an irresistible trend.Many factors,such as serious soil-borne diseases,few beneficial microorganisms and nutrient imbalance etc.,restrict the further development of ginseng production.It is an urgent scientific problem to be solved that how to regulate soil microecosystem,promote the positive succession of microbial community and effectively control soil-borne diseases.In this study,the physicochemical and microbiological characteristics of different cultivated soil of ginseng were analyzed.And the distribution of Mortierella in soil and its correlation with soil health were clarified.Furthermore,to clarify the control potential of Mortierella against soil-borne diseases,the interaction between Mortierella,Fusarium oxysporum and ginseng was analyzed by plate culture and pot experiments.The results obtained are as follows:（1）By analyzing the soil nutrients in forestland,farmland and 4-year ginseng-cultivated soil,we found that the contents of available nitrogen（NO₃^--N and NH₄⁺-N）,available phosphorus,total nitrogen,total phosphorus and organic matter were significantly different in different types of soil.High-throughput sequencing showed that Alpha diversity index indicated that the richness and diversity of bacteria and fungi in forest soil were significantly higher than that in 4-year ginseng-cultivated soil.There was high relative abundance of Mortierella in all different types of soil.And the relative abundance of Mortierella in forest soil was significantly higher than that in farmland and 4-year ginseng-cultivated soil.It is suggested that the abundance of Mortierella may be a biotic indicators of soil health.（2）An Mortierella strain was isolated from the rhizosphere of ginseng and its interaction with soil microorganisms and growth promoting potential were analyzed.The results showed that the mycelial growth of M.alpina was inhibited by probiotics such as Bacillus,Streptomyces,Brevibacterium,Trichoderma,Penicillium and potential pathogens such as Cladosporium and Aspergillus.However,there was no obvious interaction with F.oxysporum,the pathogen of ginseng root rot.M.alpina had a high indoleacetic acid production capacity,and the maximum yield was 141.37 mg/L at 4 days.And the protease activity was 5.5 U/mL at 5 days.However,M.alpina did not have the ability to produce siderophores,dissolubilize phosphorus and the activities of amylase,cellulase,pectinase and xylanase.（3）To investigate the effects of inoculation with M.alpina on the disease resistance of ginseng,pot experiment was conducted by inoculation with M.alpina（MA）,F.oxysporum（FO）and both of them（MA＿FO）.The results showed that inoculation of M.alpina in ginseng rhizosphere could significantly alleviate the symptoms of root rot.Co-inoculation of M.alpina and F.oxysporum could reduce the relative abundance of potential pathogens and increase the relative abundance of beneficial microorganisms in ginseng plants,and help the root of ginseng to build a more stable microbial network to promote the growth of ginseng plants.（4）Results of the physicochemical and microbial communities in the rhizosphere soil of ginseng inoculated with M.alpina and/or F.oxysporum showed that inoculation of M.alpina could significantly increase the contents of ammonium nitrogen,available phosphorus and available potassium and the activities of urease,sucrase and acid phosphatase.The results based on db-RDA analysis showed that ammonium nitrogen and available phosphorus content were the most important factors affecting rhizosphere bacterial and fungal communities,respectively.Linear regression analysis showed that M.alpina could resist F.oxysporum invasion by increasing the activity of soil sucrase.Combined with the analysis of soil microbial composition and the differences between groups,it was found that inoculation of M.alpina could significantly reduce the relative abundance of F.oxysporum in soil,and contribute to the positive succession of soil physicochemical and microbial communities.更多还原