Salt-inhibited protein 2-hydroxyisobutyrylation affects silique development of Arabidopsis thaliana

Lysine 2-hydroxyisobutyrylation (Khib) is one of the newly discovered post-translational modifications (PTMs) through protein acylation. It has been reported to be widely distribute in both eukaryotes and prokaryotes, and plays an important role in chromatin conformation change, gene transcription, subcellular localization, protein-protein interaction, signal transduction, and cellular proliferation. In this study, we compared the siliques from Arabidopsis thaliana under salt stress (Ss) with those in the control (Cs). The results showed that this highly conserved modification was abundant in siliques. However, there were certain significant differences between the Ss and the Cs: 3810 normalized 2-hydroxyisobutyrylation sites on 1254 proteins were identified in siliques under salt stress, and lysine 2-hydroxyisobutyrylation was up-regulated at 96 sites on 78 proteins while down-regulated at 282 sites on 205 proteins in Ss. In the KEGG pathway enrichment analysis, Khib-modified proteins were enriched in several pathways related to energy metabolism, including gluconeogenesis pathway, pentose phosphate pathway, and pyruvate metabolism. Overall, our work reveals the first systematic analysis of Khib proteome in Arabidopsis siliques under salt stress, and sheds a light on the future studies on the regulatory mechanisms of Khib during the salt stress response of plants.