Comprehensive analyses of inhibition of the Chinese traditional food-packaging materials, Indocalamus latifolius leaves (Zongye) on Aspergillus flavus

Aspergillus flavus and aflatoxins (AFs) are the most serious contaminations in food and feed. Discovery and application of plant-sourced antifungal agents are the hot-points in mycotoxin control. In this study, we focused on Zongye essential oil, which were extracted from Indocalamus latifolius leaves (the traditional packaging materials), and the antifungal and anti-toxigenic activities of different Zongye essential oil were confirmed by volatile test. Among them, No. 2 Zongye essential oil could completely inhibit the growth and toxin production of Aspergillus flavus in 10 µL treatment. Under the Zongye essential oil treatment, the evidently morphological and ultrastructural variations were observed by SEM and TEM analyses. RNA-Seq and qRT-PCR analyses partly revealed the inhibitory mechanisms: down-regulations of membrane proteins (AFLA_005560, AFLA_019420 and AFLA_084310, etc.) and conidial genes (fblC, steA and abaA, etc.) inhibited fungal development, and anti-aflatoxigenic activity might due to significant down-regulation of AFs cluster genes and global regulators (AtfA and AtfB). In addition, GC-MS identified longifolene and linalool as the major constituents of Zongye essential oil, accounting for 9.55% and 7.95% respectively. And linalool showed the stronger inhibitory abilities on fungal growth and mycotoxin biosynthesis, than longifolene. In conclusion, a novel antifungal agent, Zongye essential oil, was identified, and its inhibitory mechanism was comprehensively clarified, which is helpful to control AFs contamination in an environmental-friendly way.