Inhibition of mycelia growth and norsolorinic acid accumulation of Aspergillus parasiticus by peanut seed endophytic bacteria

Control of peanut infection by aflatoxins is a worldwide problem. In this paper, five endophytic bacteria strains isolated from peanut seeds were assayed for their inhibition to mycelia growth and norsolorinic acid accumulation using Aspergillus parasiticus NA mutant as indicated strain. Results showed four bacteria had higher inhibition ability on PGY media contained the extract of peanut seeds than on GY media without the extract of peanut seeds by visual agar plate assay. In tip culture assay, the inhibition rates of five bacteria against mycelia growth were 88.56-90.15% while the inhibition rates of norsolorinic acid accumulation were 98.79-100%. Morphological and 16S rDNA identification indicated that SKP1-2, SKP1-1 and EKP1(4) belong to Bacillus subtilis, LKP2 belongs to Bacillus amyloliquefaciens, FKP3 belongs to Bacillus pumilus. The endophytic biocontrol bacteria isolated from peanut seeds will provide us plentiful of species and bioactive substance resources to control the aflatoxin contamination in peanut effectively.