Screening and identification of an endophytic fungus from Atractylodes lancea which utilizes volatile oil selectively

Abstract

In order to transform main active ingredient of volatile oil, endophytic fungi were screened from the root of Atractylodes lancea. Transformation method was used in vitro. The changes of volatile oil were traced by gas chromatography. One endophytic fungus (strain ALG-13) which could uitilize volatile oil selectively was screened. Single factor experiment were conducted for exploring the effects of various factors that including kinds of carbon source, speed, liquid volume, pH and concentration of plant tissue on degradation by this strain. Subsequently, the main affecting factors carbon source, speed, pH and liquid volume were optimized using orthogonal array design. Results showed that endophytic fungus ALG-13 selectively used the volatile oil, change the relative percentage of the main components of volatile oil, Atractylon and Atractydin were increased, While, beta-eudesmol and Atractylol decreased. After selectively degradation by fungus, volatile oil components percentage were closer to the geo-herbs. Strain ALG-13 was identified as Bionectria ochroleuca according to its morphological characteristics and systematic analysis of ITS sequence. The optimal conditions were as follows: sucrose used as carbon source, rotating speed was 200 r x min(-1), initial pH for medium was 4.5, 50 mL liquid was added in 250 mL flask. The endophytic fungus ALG-13 could degrade the volatile oil selectively, which was benefit for forming geoherbs A. lancea volatile oil composition.