Low expression levels of the conserved nuclear histone acetyltransferase 1 restrict virus infection in plants

Potyviruses constitute the largest genus of plant-infecting RNA viruses and cause global economic losses in numerous crops. Understanding host modulation of viral pathogenicity is crucial for durable control strategy design, yet this remains poorly understood for most viruses. Here, we illustrate that the conserved host factor histone acetyltransferase 1 (HAT1) modulates viral protein acetylation, contributing to potyvirus infection in plants. By working with a prevalent potyvirus, sugarcane mosaic virus (SCMV), we uncovered that ZmHAT1 directly acetylates lysine 190 of the SCMV-encoded helper-component proteinase (HC-Pro; the main pathogenicity determinant). This acetylation is essential to sustain the double-stranded RNA affinity of HC-Pro and to maintain its stability via inhibiting ubiquitination-mediated degradation. Furthermore, the expression genome-wide association study (eGWAS) coupled with functional analysis revealed a strong association of the expression levels of Zm HAT1 with SCMV infection. Together, these findings identify a conserved pro-viral factor and a potential engineering target for broad-spectrum antiviral crops.