A proteome-wide lysine succinylome reveals TCA-related succinic acid metabolism and heat-stress responses in Reynoutria japonica.

Reynoutria japonica is an economically vital, resveratrol-producing medicinal plant whose growth and quality are increasingly threatened by climate-induced heat stress. To elucidate the post-translational mechanisms underlying thermal adaptation, we established the first comprehensive, proteome-wide lysine succinylation (Ksucc) landscape in R. japonica. A total of 1722 Ksucc sites were mapped across 650 proteins, including eight distinct sites on histones H3 and H4. Evolutionary analysis of these histone marks revealed a combination of conserved (H3K56, H3K79, H4K31, H4K77, and H4K91) and species-specific sites. Functional profiling demonstrated that succinylated proteins are heavily enriched in central metabolism, particularly photosynthesis and the tricarboxylic acid (TCA) cycle, with extensive modifications targeting key enzymes tied to succinic acid metabolism. Under acute heat stress (42 °C), R. japonica seedlings exhibited pronounced physiological chlorosis, accumulation of reactive oxygen species, and a robust global hyper-succinylation response. Beyond transcriptional screening, a combined strategy of pharmacological inhibition and in planta transient expression assays successfully identified candidate acetyltransferase RjapHAC2-like and deacetylase RjapHDA5-like as the functional writer and eraser, respectively driving Ksucc homeostasis. In conclusion, these findings provide a comprehensive lysine succinylation dataset for R. japonica and highlight its dynamic response to heat stress, offering a valuable reference for future succinylome investigations across medicinal plants.