Summary Sugar metabolism plays a vital role in plant cold tolerance. Histone acetyltransferases (HATs) act as key epigenetic regulators of stress‐responsive genes, yet the function and mechanism underlying HAT‐mediated histone acetylation (HA) in regulation of sugar metabolism under cold stress remain largely unclear. In this study, we demonstrate that PtrAHL14 and PtrAHL17, two cold‐induced AT‐hook motif‐containing nuclear‐localized proteins (AHLs) from Poncirus trifoliata , interact with TATA‐binding protein (TBP)‐Associated Factor 1 (PtrTAF1) and General Control Nonrepressed protein 5 (PtrGCN5), forming a functional quaternary complex at the nuclear matrix. The AHLs recruit PtrTAF1 and PtrGCN5 to the matrix‐associated region of PtrA/NINV7 , an alkaline/neutral invertase gene, leading to acetylation of H3K9, H3K14, H3K27, and H4K8 under cold stress. Furthermore, both HATs were found to modulate cold tolerance by cooperatively regulating PtrA/NINV7 ‐mediated accumulation of reducing sugars. PtrAHL14 and PtrAHL17 directly interact with H3 and H4 and enhance HA, while PtrTAF1 and PtrGCN5 exhibit accumulative effects on triggering HA, thereby amplifying AHL‐mediated regulation of PtrA/NINV7 . Taken together, our findings unveil a novel HATs‐AHLs‐ A/NINV7 regulatory module that epigenetically controls sucrose catabolism in response to cold stress, providing valuable insights into understanding the molecular regulation of sugar accumulation for improved cold tolerance.
Dahro et al. (Fri,) studied this question.