Arabidopsis Histone Reader EMSY-LIKE 1 Binds H3K36 and Suppresses Geminivirus Infection

Histone PTMs convey information that regulates chromatin compaction and DNA accessibility. Histone reader proteins bind specific PTMs and translate their effects by modifying chromatin and/or by recruiting effectors that alter chromatin structure or activity. In this study, CaLCuV was used to characterize the activities of twoArabidopsis Agenet domain histone readers, EML1 and EML3. We show thateml1 mutants are hypersusceptible to CaLCuV, whereaseml3 plants are more tolerant of infection than wild-type plants. We also demonstrate that EML1 and EML3 associate with histones and viral chromatinin planta and that both proteins bind peptides containing H3K36, a PTM associated with active gene expression. Consistent with antiviral activity, EML1 suppresses CaLCuV gene expression and reduces Pol II access to viral chromatin. By linking EML1 and EML3 to pathogenesis, these studies have expanded our knowledge of histone reader proteins and uncovered an additional level of viral chromatin regulation.