Horizontal gene transfer of <i>Fhb7</i> from fungus underlies <i>Fusarium</i> head blight resistance in wheat

Abstract

<i>Fusarium</i> head blight (FHB), a fungal disease caused by <i>Fusarium</i> species that produce food toxins, currently devastates wheat production worldwide, yet few resistance resources have been discovered in wheat germplasm. Here, we cloned the FHB resistance gene <i>Fhb7</i> by assembling the genome of <i>Thinopyrum elongatum</i>, a species used in wheat distant hybridization breeding. <i>Fhb7</i> encodes a glutathione S-transferase (GST) and confers broad resistance to <i>Fusarium</i> species by detoxifying trichothecenes through de-epoxidation. <i>Fhb7</i> GST homologs are absent in plants, and our evidence supports that <i>Th. elongatum</i> has gained <i>Fhb7</i> through horizontal gene transfer (HGT) from an endophytic <i>Epichloë</i> species. <i>Fhb7</i> introgressions in wheat confers resistance to both FHB and crown rot in diverse wheat backgrounds without yield penalty, providing a solution for <i>Fusarium</i> resistance breeding.