Risk Evaluation and Integrated Management of Mycotoxin in Cereals
Mycotoxin Laboratory of Institute of Food Safety and Monitoring Technology in Jiangsu Academy of Agricultural Sciences (JAAS) has been focusing on the natural occurrence, risk evaluation and management of wheat mycotoxins in Eastern China for decades. We developed rapid immune detection methods for Fusarium toxins, characterized the Fusarium graminearum species complex (FGSC) that causes mycotoxin contamination and elucidated the molecular mechanisms that regulate mycotoxin production in the fungus. We also integrated the risk management processes to control mycotoxin contamination during wheat growth, harvesting and storage. More than 40 peer-reviewed original research articles have been published, 10 of which in SCI indexed journals. In addition, 5 patents have been registered and granted.
Natural occurrence of mycotoxin in Eastern China
Fusarium head blight (FHB), caused by Fusarium graminearum species complex (FGSC), is a devastating wheat disease in China. The disease epidemics not only can lead to significant yield losses but also can reduce grain quality by mycotoxin contamination in the infected grains. Grains contaminated by mycotoxins [e.g. deoxynivalenol (DON), nivalenol and zearalenone] are unsafe for human consumption and animal feed and thus pose a serious threat to food safety.
We have developed HPLC-MS/MS assay and ELISA to detect various mycotoxins (e.g., deoxynivalenol and zearalenone) in wheat. With these methods, we monitored the mycotoxin prevalence in Yangtze and Huai River valley and evaluate the risk of mycotoxin contamination in wheat.
Molecular characterization of the FGSC in Eastern China
Members of the Fusarium graminearum species complex (FGSC) cause Fusarium head blight in small cereal grains all over the world. We have determined the species and trichothecene chemotypes composition and population structure of FGSC in Jiangsu and Anhui provinces, where epidemics occur frequently in the past.
Molecular regulation mechanisms of mycotoxin biosynthesis
Targeted gene deletion or silencing technology is used to study the molecular regulation mechanisms of fungal mycotoxin biosynthesis; we have identified several genes that are essential for mycotoxin biosynthesis and other important fungal cellular activities.
Integrated mycotoxin management
1. Bio-control of mycotoxin-producing Fusarium spp.
We have screened bacterial strains that have antagonistic activity against Fusarium spp. from wheat and soil samples. The inhibitory mechanisms of these bacterial strains were investigated; and the chemical compounds or proteins which are effectively against Fusarium spp. were also separated and identified.
2. Detoxification of mycotoxin-contaminated grains
Recently, a bacterial strain A16 was isolated from wheat growing soil and exhibited the capability of degrading DON. On the basis of morphological, physiological and phylogenetic analysis of its 16SrDNA sequence, strain A16 was identified as a bacterium belonging to Devosia sp. This strain showed a rapid DON degrading rate and has a potential in the application for detoxification of DON-contaminated grains.
3. Host-induced gene silencing (HIGS) of crucial genes of mycotoxin biosynthesis or regulation
We planned our further researches to silence crucial mycotoxin biosynthesis or to regulate genes to control the disease and mycotoxin contamination through HIGS in Arabidopsis thaliana.
1. Ji, F., Li, H., Xu, J., & Shi, J. (2011). Enzyme-linked immunosorbent-assay for deoxynivalenol (DON). Toxins, 3(8), 968-978.
2. Qiu J, Xu J, Shi J. (2014). Molecular characterization of the Fusarium graminearum species complex in Eastern China. European Journal of Plant Pathology, 1-13.
3. Qiu J, Shi J. (2014). Genetic Relationships, Carbendazim sensitivity and mycotoxin production of the Fusarium graminearum populations from maize, wheat and rice in Eastern China. Toxins, 6(8): 2291-2309.
4. Ji, F., Xu, J., Liu, X., Yin, X., & Shi, J. (2014). Natural occurrence of deoxynivalenol and zearalenone in wheat from Jiangsu province, China. Food chemistry, 157, 393-397.
5. Xu, J., Deng, P., Showmaker, K. C., Wang, H., Baird, S. M., & Lu, S. E. (2014). The pqqC gene is essential for antifungal activity of Pseudomonas kilonensis JX22 against Fusarium oxysporum f. sp. lycopersici. FEMS microbiology letters, 353(2), 98-105.
6. Liu X, Wang J, Xu J, Shi J. (2014). FgIlv5 is required for branched-chain amino acid biosynthesis and full virulence in Fusarium graminearum. Microbiology, 160(Pt 4): 692-702.
7. Liu, X., Xu, J., Wang, J., Ji, F., Yin, X., & Shi, J. (2014). Involvement of threonine deaminase FgIlv1 in isoleucine biosynthesis and full virulence in Fusarium graminearum. Current genetics, 1-11.