Quantitative proteome and acetylome analyses uncover integrated drought resistance mechanisms in rice

Drought stress significantly reduces rice productivity, necessitating efforts to understand resistance mechanisms. This study utilizes quantitative proteomic and lysine acetylomic analyses to elucidate the complex drought responses in three rice cultivars with distinct drought resistance strategies. Proteomic analysis reveals that Hanyou73, an integrated drought avoidance and drought tolerance cultivar, exhibits exceptional resistance to water deprivation compared to other cultivars. Critically, lysine acetylomic analysis underscores the pivotal role of histone acetylation, particularly H4K5ac, in modulating water management efficiency, which underpins Hanyou73's drought resilience. Leveraging this enhanced water management, Hanyou73 exhibits superior photosynthetic efficiency under drought conditions, primarily attributed to the deacetylation of ATP synthase beta subunit (AtpB) at K100, thereby augmenting ATPase catalytic activity. Additionally, deacetylation of phosphoglucomutase (PGM) at K155 indicated an adaptive metabolic response across all drought-resistant cultivars, ensuring sustained energy and metabolic intermediate supply crucial for broad adaptation mechanisms. Collectively, these findings elucidate the intricate regulatory networks in Hanyou73, highlighting its sophisticated balance between drought avoidance and tolerance strategies. This research offers valuable insights into the proteomic and lysine acetylomic dynamics underlying rice drought resistance, providing potential biomarkers for breeding towards genetic enhancement. Overall design: ChIP-seq analysis of histone H4K5ac in rice cultivar Hanyou73 leaves under both well-watered (WW) and drought-stressed (DS) conditions.