Histone Deacetylase 19 Controls Powdery Mildew Susceptibility by Attenuating Biosynthesis of Cuticular Wax and Salicylic Acid

Phytopathogenic Ascomycetes <i>Blumeria graminis</i> f. sp. <i>tritici</i> (<i>Bgt</i>) causes wheat powdery mildew disease and impacts global wheat production. Decoding the molecular wheat-<i>Bgt</i> interaction could facilitate the wheat disease resistance breeding. In this study, we elucidated that wheat histone deacetylase 19 (TaHDA19) regulates susceptibility to <i>Bgt</i> pathogen by suppressing biosynthesis of cuticular wax and salicylic acid (SA). Knockdown of wheat <i>TaHDA19</i> gene expression led to in enhanced cuticular wax and SA accumulation, potentiated <i>Bgt</i> conidia germination and appressoria formation, attenuated formation of <i>Bgt</i> haustoria and microcolonies. Histone deacetylase TaHDA19 is enriched at the <i>TaECR</i> and <i>TaSARD1</i> promoter regions to facilitate histone deacetylation, and thus suppressing <i>TaECR</i> and <i>TaSARD1</i> transcription. In addition, we identified cuticular wax and SA regulated by TaHDA19 as chemical cues determining wheat pre- and postsusceptibility to <i>Bgt</i> pathogen. These findings collectively support that the wheat histone deacetylase TaHDA19 epigenetically suppresses cuticular wax and SA biosynthesis, thereby dampening chemical cues essential for the wheat powdery mildew susceptibility.