Lysine 2-Hydroxyisobutyrylation- and Succinylation-Based Pathways Act Inside Chloroplasts to Modulate Plant Photosynthesis and Immunity

Abstract

Crops must efficiently allocate their limited energy resources to survival, growth and reproduction, including balancing growth and defense. Thus, investigating the underlying molecular mechanism of crop under stress is crucial for breeding. Chloroplasts immunity is an important facet involving in plant resistance and growth, however, whether and how crop immunity modulated by chloroplast is influenced by epigenetic regulation remains unclear. Here, the cotton lysine 2-hydroxyisobutyrylation (Khib) and succinylation (Ksuc) modifications are firstly identified and characterized, and discover that the chloroplast proteins are hit most. Both modifications are strongly associated with plant resistance to Verticillium dahliae, reflected by Khib specifically modulating PR and salicylic acid (SA) signal pathway and the identified GhHDA15 and GhSRT1 negatively regulating Verticillium wilt (VW) resistance via removing Khib and Ksuc. Further investigation uncovers that photosystem repair protein GhPSB27 situates in the core hub of both Khib- and Ksuc-modified proteins network. The acylated GhPSB27 regulated by GhHDA15 and GhSRT1 can raise the D1 protein content, further enhancing plant biomass- and seed-yield and disease resistance via increasing photosynthesis and by-products of chloroplast-derived reactive oxygen species (cROS). Therefore, this study reveals a mechanism balancing high disease resistance and high yield through epigenetic regulation of chloroplast protein, providing a novel strategy to crop improvements.