Biological control of Aspergillus flavus infection and growth promotion of peanut seedlings by Lactiplantibacillus plantarum and Levilactobacillus brevis.

Background: Aspergillus spp. infection might induce negative effects on peanut seeds, including decreased germination rates and suppressed seedling vigor. Furthermore, A. flavus can secret aflatoxin, regarding food safety and human health. The prolonged use of fungicides for treating mold infections has raised concerns regarding the emergence of fungicide-resistant strains, environmental pollution, and adverse effects on human health. The usage of lactic acid bacteria, including Lactiplantibacillus plantarum and Levilactobacillus brevis for the management of plant diseases, has garnered increasing attention in recent years as a viable alternative to chemical-based therapies. This study aimed to investigate the efficacy of LABs in pre-treating peanut seeds as a biological solution against A. flavus infection before cultivation. Results: Lactiplantibacillus plantarum and Levilactobacillus brevis have demonstrated the ability to suppress A. flavus in vitro. In the in vivo investigation, pre-treatment of peanut seeds with cell-free supernatant derived from L. plantarum (LP-CFS) and L. brevis (LB-CFS) significantly reduced A. flavus infection levels. The conidial count decreased from 8.63 log conidia/g in the untreated group to 5.35 log conidia/g with LP-CFS treatment and 4.59 log conidia/g with LB-CFS treatment. Additionally, A. flavus infection reduced the germination rate of peanut seeds to only 20.4% compared to 63.6% in the control group. In comparison, pre-treatment with LP-CFS and LB-CFS increased the germination rate to 75.6% and 76.8%, respectively, and further improved the vigor index in A. flavus-infected peanut seeds. Conclusion: The present findings indicated that bioactive compounds derived from L. plantarum and L. brevis emerge as promising candidates for treating peanut seeds, effectively protecting them against A. flavus infection. Moreover, these compounds facilitate the growth of seedlings, which could be a potential alternative to chemical fungicides, and contribute to sustainable agricultural development. [ABSTRACT FROM AUTHOR]