L-Cysteine hydrochloride inhibits Aspergillus flavus growth and AFB1 synthesis by disrupting cell structure and antioxidant system balance

• Published in: Journal of hazardous materials 2023-10, Vol.459, p.132218-132218, Article 132218
• Main Authors: Qiu, Mei, Qiu, Lihong, Deng, Qi, Fang, Zhijia, Sun, Lijun, Wang, Yaling, Gooneratne, Ravi, Zhao, Jian
• Format: Article
• Language: English
• Subjects: Aflatoxin; Aspergillus flavus; Cell wall remodeling; Dwarf mycelium; L-Cysteine hydrochloride
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.132218

Aflatoxin B1 (AFB1) is the most potent known naturally occurring carcinogen and pose an immense threat to food safety and human health. L-Cysteine hydrochloride (L-CH) is a food additive often used as a fruit and vegetable preservative and also to approved bread consistency. In this study, we investigated the effects and mechanisms of L-CH as an antimicrobial on the growth of Aspergillus flavus (A. flavus) and AFB1 biosynthesis. L-CH significantly inhibited A. flavus mycelial growth, affected mycelial morphology and AFB1 synthesis. Furthermore, L-CH induced glutathione (GSH) synthesis which scavenged intracellular reactive oxygen species (ROS). RNA-Seq indicated that L-CH inhibited hyphal branching, and spore and sclerotia formation by controlling cell wall and spore development-related genes. Activation of the GSH metabolic pathway eliminated intracellular ROS, leading to hyphal dwarfing. L-CH treatment downregulated most of the Aflatoxin (AF) cluster genes and aflS, aflR, AFLA_091090 transcription factors. This study provides new insights into the molecular mechanism of L-CH control of A. flavus and AFB1 foundation. We believe that L-CH could be used as a food additive to control AFB1 in foods and also in the environment. [Display omitted] •L-CH inhibited A. flavus development and AFB1 production.•L-CH inhibited hyphal branching and delayed cell wall remodeling.•L-CH synthesized glutathione and reduced ROS.•Most AFB1 cluster genes were suppressed by L-CH.•AFLA_091090 gene could be a potential indicator of L-CH anti-AF in A. flavus.