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目的:从茅苍术Atractylodes lancea根中分离内生真菌,筛选能选择性降解转化茅苍术挥发油的菌株,实现内生真菌对茅苍术挥发油主要成分的转化作用。方法:利用微生物体外转化方法,通过气相色谱追踪挥发油变化,筛选出能选择性利用挥发油的内生真菌。通过单因素试验研究碳源、转速、装液量、初始pH和植物组织添加对内生真菌降解的影响,并选取对降解影响较大的因素进行正交试验。结果:筛选到的内生真菌ALG-13可以选择性利用挥发油,改变了挥发油主要成分相对百分比。总体表现为苍术酮和苍术素增加,β-桉叶醇和茅术醇含量减少。经过真菌选择性降解后,挥发油组分更加接近道地茅苍术的挥发油组成。ALG-13基于形态特征、ITS序列系统学分析,确定为生赤壳属真菌Bionectria ochroleuca。最优降解条件为200 r.min-1,pH 4.5,250 mL装液量为50 mL、蔗糖为碳源。结论:内生真菌ALG-13可以选择性降解挥发油,使挥发油组分接近道地药材。
OBJECTIVE: To isolate endophytic fungi from Atractylodes lancea roots and select the strains that can selectively degrade the volatile oil of Atractylodes lancea, and to achieve the transformation of the main components of the essential oil of Atractylodes lancea. Methods: Microbial in vitro transformation method was used to trace the change of volatile oil by gas chromatography, and the endophytic fungi that could selectively utilize volatile oil were screened out. The effects of carbon source, rotation speed, liquid volume, initial pH and plant tissue on the degradation of endophytic fungi were studied by single factor experiments. The factors affecting the degradation were selected for orthogonal experiment. Results: The selected endophytic fungi ALG-13 can selectively use the volatile oil, changing the relative percentage of the main components of the volatile oil. The overall performance of atractylodes and atractylodes increased, β-eucalyptol and methotrexate decreased. After fungal selective degradation, the volatile oil components are more closely related to the volatile oil of Atractylodes. ALG-13 was identified as Bionectria ochroleuca based on phylogenetic analysis and ITS sequence analysis. The optimum degradation conditions were 200 r.min-1, pH 4.5, 250 mL liquid volume 50 mL and sucrose as carbon source. Conclusion: The endophytic fungus ALG-13 can selectively degrade the volatile oil and make the components of volatile oil close to the authentic medicinal materials.