[Isolation and Identification of Antagonistic Endophytic Actinomycetes Against Root Rot Disease in Ligusticum chuanxiong].

Objective: To get an understanding of the microflora of endophytic actinomycetes in Ligusticum chuanxiong,and to obtain the resource of antagonistic strains against Ligusticum chuanxiong root rot disease. Methods: Actinomycetes in stem nodes and rhizomes of Ligusticum chuanxiong were isolated and purified by a series of means,namely tissue block method, homogenate technique and plat streaking method. Further, dual culture and inhibition zone method were employed to test the antagonistic activity of these strains. To identify strains with potential precisely,both microscopic observation and DNA sequencing were conducted. Results: 83 strains of Ligusticum chuanxiong endophytic actinomycetes were identified, which consisted of 13 species groups. Among all of them,species identified as Streptomyces scopuliridis( KF600747. 1), Streptomyces griseorubiginosus( AB706352. 1) and Streptomyces agglomeratus( LC055413. 1) showed antagonistic activities against four kinds of pathogenic fungi of Ligusticum chuanxiong root rot disease. Conclusion: Actinomycetes which belong to Griseorubroviolaceus groups of streptomyce are potential biocontrol microbes to Ligusticum chuanxiong root rot,showing importance to the production of Chuanxiong Rhizoma.

[Identification of Pathogens Causing Root Rot Disease on Ligusticum chuanxiong in Sichuan].

OBJECTIVE: To identify the pathogens causing root rot disease on Ligusticum chuanxiong from the main producing areas in Sichuan, and to provide gist of management of this disease in the future. METHODS: The diseased rhizomes of Ligusticurn chuanxiong with root rot symptom were sampled in two main producing areas in Sichuan. According to Koch's postulate, the pathogenicity on Ligusticum chuanxiong rhizomes of the isolates was confirmed. The representative isolates were identified based on their morphological characteristics and ribosomal DNA internal transcribed spacer(rDNA-ITS) sequences. RESULTS: The isolates(f2-16, 3-2, f4-19 and f5-7)which caused root rot disease held high homology reached 99%, 99%, 100% and 100% respectively, when compared with GenBank sequences GQ229075, JQ796755, JN232136 and FJ481024. CONCLUSION: The causing agents of root rot disease on Ligusticum chuanxiong belong to Fusarium solani, Fusarium oxysporum, Plectosphaerella cucumerina and Phoma glomerata. Pathogens from different regions are varied.