Comprehensive Analysis of Lysine Lactylation in Rice (Oryza sativa) Grains

Protein
lysine lactylation is a new post-translational modification
(PTM) prevalently found in fungi and mammalian cells that directly
stimulates gene transcription and regulates the glycolytic flux. However,
lysine lactylation sites and regulations remain largely unexplored,
especially in cereal crops. Herein, we report the first global lactylome
profile in rice, which effectively identified 638 lysine lactylation
sites across 342 proteins in rice grains. Functional annotations demonstrated
that lysine lactylation was enriched in proteins associated with central
carbon metabolism and protein biosynthesis. We also observed that
proteins serving as nutrition reservoirs in rice grains were frequently
targeted by lactylation. Homology analyses indicated that lactylation
was conserved on both histone and nonhistone proteins across plants,
human cells, and fungi. In addition to lactylation, additional types
of acylations could co-occur in many proteins at identical lysine
residues, indicating potential cross-talks between these modifications.
Our study provided a comprehensive profile of protein lysine lactylation
in cereal crop grains.