Morphological and Transcriptomic Analysis of the Inhibitory Effects of Lactobacillus plantarum on Aspergillus flavus Growth and Aflatoxin Production

<i>Lactobacillus plantarum</i>, as a natural bio-preservative, has attracted a great deal of attention in recent years. In this study, 22 L<i>. plantarum</i> strains were tested against the aflatoxin-producing fungus, <i>Aspergillus flavus</i>; strain IAMU80070 showed the highest antifungal activity. At a concentration of 5 × 10⁵ colony-forming units (CFU) mL^-1, it completely inhibited <i>A. flavus</i> growth and decreased aflatoxin production by 93%. Furthermore, ultrastructural examination showed that IAMU80070 destroyed the cellular structure of hyphae and spores. To explore the inhibitory effect of IAMU80070 on <i>A. flavus</i> at the transcriptional level, transcriptome data were obtained and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The aflatoxin biosynthetic process was the most significantly downregulated functional category, while genes implicated in the synthesis and organization of cell wall polysaccharides were upregulated. Quantitative real-time PCR results verified the credibility and reliability of the RNA sequencing data. These results provided insight into the transcriptome of <i>A. flavus</i> in response to the antagonistic effects of <i>L. plantarum</i> IAMU80070.