Reduction of aflatoxin contamination in maize kernels mediated by host-induced gene silencing
- 1Genome Center, University of California, Davis, CA 95616
- 2Department of Plant Pathology, University of California, Davis, CA 95616
- 3Department of Plant Sciences, University of California, Davis, CA 95616
Abstract
Aflatoxins produced by some species of Aspergillus pose a significant threat to global food safety, because they contaminate a variety of crops including maize. In this study, we used host-induced gene silencing (HIGS) to reduce aflatoxin accumulation in maize upon infection with Aspergillus flavus and Aspergillus parasiticus. Two RNAi constructs were designed and introduced into maize, one targeting two essential fungal genes involved in ergosterol biosynthesis (CYP51A and CYP51B) and the other targeting three aflatoxin biosynthesis genes (AflC, AflD, and AflR). The presence of RNAi transgenes was confirmed in 17 and 14 independent lines possessing the CYP51A/CYP51B RNAi construct and the AflC/AflD/AflR RNAi construct, respectively. Most transgenic lines had single-locus integrations and one or two copies of the transgene. Transgene expression varied considerably among the lines. Small RNA sequencing confirmed the production of siRNAs from the HIGS trigger sequences. Levels of CYP51A, AflC, AflD, and AflR transcripts in Aspergillus spp. were successfully decreased upon infection of transgenic maize. However, significant reduction in the level of CYP51B transcripts was not achieved and the CYP51A/CYP51B RNAi transgene had no discernible effect on fungal growth in infected maize. In contrast, we observed significant reductions in aflatoxin accumulation in four AflC/AflD/AflR RNAi transgenic lines infected with A. flavus and in two transgenic lines infected with A. parasiticus. Notably, one AflC/AflD/AflR transgenic line exhibited minimal aflatoxin contamination upon kernel infection with A. parasiticus. These results demonstrate the potential of HIGS to reduce aflatoxin production in mature corn kernels.
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BibTeX
@article{ahmed2026reduction,
title = {{Reduction of aflatoxin contamination in maize kernels mediated by host-induced gene silencing}},
author = {Ali Ahmed and Keri Cavanaugh and Patricia Baldrich and Ioannis Stergiopoulos and Richard Michelmore},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
year = {2026},
month = oct,
doi = {10.1073/pnas.2620406123},
url = {https://doi.org/10.1073/pnas.2620406123},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Reduction of aflatoxin contamination in maize kernels mediated by host-induced gene silencing
AU - Ali Ahmed
AU - Keri Cavanaugh
AU - Patricia Baldrich
AU - Ioannis Stergiopoulos
AU - Richard Michelmore
PY - 2026
DA - 2026/10/22
JO - Proceedings of the National Academy of Sciences of the United States of America
DO - 10.1073/pnas.2620406123
UR - https://doi.org/10.1073/pnas.2620406123
AB - Aflatoxins produced by some species of Aspergillus pose a significant threat to global food safety, because they contaminate a variety of crops including maize. In this study, we used host-induced gene silencing (HIGS) to reduce aflatoxin accumulation in maize upon infection with Aspergillus flavus and Aspergillus parasiticus. Two RNAi constructs were designed and introduced into maize, one targeting two essential fungal genes involved in ergosterol biosynthesis (CYP51A and CYP51B) and the other targeting three aflatoxin biosynthesis genes (AflC, AflD, and AflR). The presence of RNAi transgenes was confirmed in 17 and 14 independent lines possessing the CYP51A/CYP51B RNAi construct and the AflC/AflD/AflR RNAi construct, respectively. Most transgenic lines had single-locus integrations and one or two copies of the transgene. Transgene expression varied considerably among the lines. Small RNA sequencing confirmed the production of siRNAs from the HIGS trigger sequences. Levels of CYP51A, AflC, AflD, and AflR transcripts in Aspergillus spp. were successfully decreased upon infection of transgenic maize. However, significant reduction in the level of CYP51B transcripts was not achieved and the CYP51A/CYP51B RNAi transgene had no discernible effect on fungal growth in infected maize. In contrast, we observed significant reductions in aflatoxin accumulation in four AflC/AflD/AflR RNAi transgenic lines infected with A. flavus and in two transgenic lines infected with A. parasiticus. Notably, one AflC/AflD/AflR transgenic line exhibited minimal aflatoxin contamination upon kernel infection with A. parasiticus. These results demonstrate the potential of HIGS to reduce aflatoxin production in mature corn kernels.
SN - 0027-8424
SN - 1091-6490
ER -