Kbhb Proteome Resource Reveals a Metabolic-Epigenetic Crosstalk Governing Rice Blast Resistance via OsACLA2 Activity...

Lysine β-hydroxybutyrylation (Kbhb) is a metabolite-derived post-translational modification linking metabolism to epigenetic and cellular regulation. Although studied in mammals, its prevalence and roles in plants remain unclear. Here, we report the first proteome-wide profiling of Kbhb in rice leaves, identifying 656 sites on 482 proteins implicated in diverse biological processes including photosynthesis and central metabolism. We show that Kbhb at conserved K262 of ATP-citrate lyase OsACLA2 enhances its activity. This modification is essential for full resistance to rice blast, as K262 mutants exhibit compromised immunity. Moreover, we identify histone deacetylase OsHDA705 as an eraser that dynamically removes Kbhb from OsACLA2. Our results establish Kbhb as a key regulatory mechanism integrating metabolic signaling with plant defense, revealing a novel pathway where β-hydroxybutyrate fine-tunes metabolic enzyme activity to orchestrate effective immunity. This study provides a foundational resource and novel insights for engineering disease resistance in crops.