RNA interference (RNAi) as a potential tool for control of mycotoxin contamination in crop plants: concepts and considerations

Authors: Majumdar, Raj; Rajasekaran, Kanniah - Rajah; Cary, Jeffrey

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2017
Publication Date: 2/14/2017
Citation: Majumdar, R., Rajasekaran, K., Cary, J.W. 2017. RNA interference (RNAi) as a potential tool for control of mycotoxin contamination in crop plants: concepts and considerations. Frontiers in Plant Science. 8:200. https://doi.org/10.3389/fpls.2017.00200.
DOI: https://doi.org/10.3389/fpls.2017.00200

Interpretive Summary: Mycotoxin contamination in food and feed crops is a major concern worldwide. Fungal pathogens belonging to the genera Aspergillus, Fusarium, and Penicillium are major bio-contaminants of crop plants due to production of mycotoxins such as aflatoxins, fumonisins, patulin, and other toxic secondary metabolites. These toxic compounds substantially reduce the value of the crop and pose a significant threat to human health. Traditional host ‘resistance gene’ mediated disease resistance approaches are often compromised by evolving pathogens in the long run. As an alternative, RNA interference (RNAi) represents a robust pre-harvest mycotoxin control tool to combat phytopathogenic fungi. Successful RNAi implementation depends on several factors including efficient vector design for maximum gene knock down effect, availability of ample target small interfering RNAs (siRNAs) at the infection site, efficient uptake of siRNAs by the fungus, siRNA half-life and amplification and perpetuation of the silencing effect. This review provides a critical and comprehensive evaluation of the published literature on use of RNAi-based approaches in crop plants to control mycotoxin contamination. It also highlights knowledge gaps that need to be addressed in order to fine tune this technology and make it more effective against mycotoxigenic fungi as well as eco-friendly in future.

Technical Abstract: Mycotoxin contamination in food and feed crops is a major concern worldwide. Fungal pathogens of the genera Aspergillus, Fusarium, and Penicillium are a major threat to food and feed crops due to production of mycotoxins such as aflatoxins, 4-deoxynivalenol, patulin, and numerous other toxic secondary metabolites that substantially reduce the value of the crop. While host resistance genes are frequently used to introgress disease resistance into elite germplasm, either through traditional breeding or transgenic approaches, such resistance is often compromised by the evolving pathogen over time. RNAi-based host-induced gene silencing (HIGS) of key genes required by the pathogen for optimal growth, virulence and/or toxin production, can serve as an alternative approach for disease control. RNAi represents a robust and efficient tool that can be used in a highly targeted, tissue specific manner to combat mycotoxigenic fungi infecting crop plants. Successful RNAi implementation depends on several factors including vector designs that incorporate sequences of target genes that will generate siRNA species for maximum gene knock down effect, availability of ample target siRNAs at the infection site, efficient uptake of siRNAs by the fungus, siRNA half-life and amplification of the silencing effect. This review provides a critical and comprehensive evaluation of the published literature on use of RNAi-based approaches to control mycotoxin contamination in crop plants. It also examines experimental strategies used to better understand the mode of action of RNAi with the aim of eliminating mycotoxin contamination, thereby improving food and feed safety.