Abstract
Auricularia auricula is one of the main edible fungi widely cultivated in China. Aspergillus flavus that is the most common class of pathogenic bacteria fungi produced the high toxicity of the aflatoxins, which is one of the fungal diseases of A. auricula. Morphological observation of A. flavus mycelium and A. auricula mycelium in plate confrontation, mutual inhibition of growth at different germination times, and the interaction of A. flavus liquid culture solution and A. flavus volatiles with A. auricula mycelium were used to investigate the mechanism of the interaction between A. flavus and A. auricula mycelium. Mycelium of A. auricula and A. flavus had a mutual inhibitory effect, but A. auricula mycelia had stronger inhibitory effect on the growth of A. flavus mycelia, besides that the results of the interaction between A. flavus volatiles and A. auricula volatiles were also the same and the inhibition of A. flavus by volatiles from A. auricula mycelium about 11%. After 240 h, the inhibition rate of A. flavus liquid culture solution on A. auricula mycelium reached up to about 20%. It was analyzed that some antimicrobial substances such as small peptides and organic acids produced in the metabolites of A. flavus liquid culture solution were the main reasons of the growth inhibition of A. auricula mycelium. The main inhibitory substances were 2-Butanone, 2-Butanone dimer, etc. Further study of AFT B1 and AFT B2 revealed that aflatoxins could migrate from the medium to the mycelia and the fruiting body of A. auricula, but the migration rate was basicly lower than 10‱. The mycelia of A. auricula had strong degradation of aflatoxins in the growth process. So the mechanism of antifungal activity of these substances was studied to provide a theoretical basis for future chemical synthesis.