Emerging trends in protein post-translational modifications of lysine associated with plant stress and development

Post-translational modifications (PTMs) of proteins represent central regulatory mechanisms within cells, enabling rapid and targeted modulation of protein functions. PTMs can directly influence protein activity, stability, or protein-protein interactions, while histone modifications also play a crucial role in gene expression regulation. To date, over 400 types of PTMs have been identified, with new types continually emerging. Among these, lysine lactylation (Kla), crotonylation (Kcr), and lysine 2-hydroxyisobutyrylation (Khib) have recently been recognized as novel PTMs with critical roles in plant growth, development, and stress responses. Unlike previous reviews that broadly summarize plant PTMs, this article provides a focused synthesis on these three newly characterized acylations, highlighting their distinct biochemical features, regulatory mechanisms, and functional relevance in plant growth, development, and stress adaptation. We summarize recent proteomic and functional studies that uncover (i) the role of histone and non-histone lactylation in metabolic reprogramming and stress resilience; (ii) the contribution of crotonylation to transcriptional regulation, enzyme activity, and abiotic stress tolerance; and (iii) the emerging function of 2-hydroxyisobutyrylation in photosynthesis, stem development, and plant pathogen interactions. Furthermore, we discuss cross-talk among Khib, Kcr, and Kac (lysine acetylation), revealing a coordinated acylation network that fine-tunes chromatin dynamics and metabolic homeostasis. By integrating findings across multiple species including rice, wheat, maize, pepper, and fungi this review proposes a comparative and mechanistic framework for understanding how these acylations bridge cellular metabolism with epigenetic and physiological regulation.