Peanuts that keep aflatoxin at bay: A threshold that matters

Aflatoxin contamination in peanuts is a major challenge for health and nutrition in both humans and livestock. In this article Sharma et al., provide convincing data that over-expression of defensin genes, or down-regulation of aflatoxin biosynthetic genes through host-induced gene silencing, can significantly reduce aflatoxin contamination of inoculated peanut seeds.

Peanuts that keep aflatoxin at bay: A threshold that matters

Kiran K. Sharma; Arunima Pothana; Kalyani Prasad; Dilip Shah; Jagdeep Kaur; Deepak Bhatnagar; Zhi-Yuan Chen; YenjitRaruang; Jeffrey W. Cary; Kanniah Rajasekaran; Hari Kishan Sudini and Pooja Bhatnagar-Mathur (2017). Plant Biotechnology Journal, Vol 15, DOI: 10.1111/pbi.12846.

http://onlinelibrary.wiley.com/doi/10.1111/pbi.12846/abstract

Aflatoxin contamination in peanuts is a major challenge for health and nutrition in both humans and livestock. In this article Sharma et al., provide convincing data that over-expression of defensin genes, or down-regulation of aflatoxin biosynthetic genes through host-induced gene silencing, can significantly reduce aflatoxin contamination of inoculated peanut seeds. As aflatoxin biosynthesis is a complicated process, involving many levels of transcriptional and post-transcriptional controls, the authors based their strategy on using transgenics and HIGS tools to generate peanut plants with improved genetic resistance to Aspergillus flavus infection and aflatoxin contamination. By over-expressing antifungal plant defensins MsDef1 and MtDef4.2, and through host-induced gene silencing of aflM and aflP genes from the aflatoxin biosynthetic pathway, the authors were able to demonstrate that the former improves genetic resistance to A. flavus infection, and the latter inhibits aflatoxin production in the event of infection, thus providing a double shield. This study is the first to demonstrate success in generating peanuts that are near-immune to aflatoxin contamination. The work lays the foundation for the development of improved peanut germplasm with enhanced resistance to A. flavus and opens new perspectives for the development of aflatoxin resistance strategies in other major food crops. Deployment of these technologies has tremendous potential not only for health and food safety, but also for translating to better export markets, which have declined by almost half in the last decade due to unacceptable levels of aflatoxin contamination.

Jim Ruddock, Managing Editor.

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