NX Trichothecenes Are Required for Fusarium graminearum Infection of Wheat

作者：Guixia Hao, Susan P. McCormick, Helene Tiley, Santiago Gutiérrez, Gabdiel Yulfo-Soto, Martha Vaughan, Todd J. Ward · 发表于：Molecular Plant-Microbe Interactions · 年份：2023 · DOI：10.1094/mpmi-08-22-0164-r · 被引用次数：25 · 研究领域：Mycotoxins in Agriculture and Food、Plant Pathogens and Fungal Diseases、Plant-Microbe Interactions and Immunity

Fusarium graminearum causes Fusarium head blight (FHB) on wheat and barley and contaminates grains with various mycotoxins that are toxic to humans and animals. Deoxynivalenol (DON), a type B trichothecene, is an essential virulence factor that is required for F. graminearum to spread within a wheat head. Recently, novel type A trichothecenes NX-2 and NX-3 (NX) have been found in F. graminearum. NX trichothecenes lack a keto group at the C8 position. To determine if NX trichothecenes play a role similar to that of DON during F. graminearum infection, deletion mutants of TRI5, the first gene for trichothecene biosynthesis, were generated from strains PH-1, NRRL46422, and NRRL44211 (hereafter 44211) representing the 15-acetyl-DON, 3-acetyl-DON, and NX chemotypes. No trichothecene production was detected in any of the Δ tri5 mutants in cultures or inoculated wheat heads. FHB symptoms were restricted to the inoculated wheat spikelets when point-inoculated with the Δ tri5 mutants, confirming the necessity of NX and DON for FHB spread. Furthermore, whole-head dip inoculations revealed significant reductions in disease and fungal biomass in wheat heads inoculated with 44211Δ tri5 compared with 44211. Introduction of the native 44211 TRI5 and a Trichoderma arundinaceum TRI5 ortholog in the 44211Δ tri5 mutant complemented trichothecene production in vitro; however, introducing both TRI5 partially restored wild-type levels of NX in infected heads. Our results demonstrate that NX tricho...