Peanuts that keep aflatoxin at bay: A threshold that matters

Aflatoxins are small molecules that are extremely damaging to human health that are produced by the fungal species Aspergillus flavus and Aspergillus parasiticus.  Peanut pods form underground and so are particularly vulnerable to infection by the fungus. Sharma et al. used a two-pronged approach to develop peanuts that accumulate little or no aflatoxin. On the one hand, they introduced defensin genes from related legumes (Medicago sativa and Medicago truncatula; MsDef1 and MtDef4.2) that confer increased resistance to fungal infection. On the other hand, they introduced into the peanut host a construct that suppresses aflatoxin biosynthesis in the fungus through host-induced gene silencing (HIGS). Peanuts engineered with the defensin and HIGS contructs accumulated neglible amounts of aflatoxins. Plant Biotech. J. 10.1111/pbi.12846