Lysine succinylation mediates defense responses against viruses and herbivores in rice

Lysine succinylation is an important post-translational modification that regulates metabolism and transcription. Although lysine succinylation has been characterized during rice development, its role in plant responses to biotic stress remains largely unknown. By quantitative succinylome profiling of rice subjected to viral infection and herbivore infestation, we identify extensive, stress-responsive lysine succinylation on both histone and non-histone proteins. Lysine succinylation preferentially targets highly abundant proteins and is enriched in pathways associated with photosynthesis and metabolism. CUT&Tag analysis reveals strong lysine succinylation enrichment at promoters of defense-related genes, particularly those involved in plant hormone signal transduction, and demonstrates a positive correlation between lysine succinylation occupancy and gene expression. We further identify three rice histone deacetylases, OsSRT702, OsHDA714, and OsHDA716, as major desuccinylases involved in lysine succinylation removal. Functional analyses show that disruption of OsHDA714 markedly enhances resistance to rice stripe virus, rice black-streaked dwarf virus, the brown planthopper, and the striped stem borer. Integrated transcriptomic and CUT&Tag analyses reveal that genes upregulated in the hda714 knockout mutant are predominantly enriched in the phenylpropanoid biosynthesis pathway, with many carrying lysine succinylation marks in their promoter regions. In addition, jasmonate-associated defense pathways are activated in the mutant, indicating that lysine succinylation promotes defense-related transcriptional reprogramming. This study reveals a previously unrecognized role of lysine succinylation in coordinating rice defense against diverse biotic stresses. We identify OsHDA714 as a key negative regulator of immunity and propose that OsHDA714-mediated desuccinylation modulates hormone signaling and phenylpropanoid metabolism to control broad-spectrum resistance in rice.