https://www.selleckchem.com/ The pad2 mutant accumulated ascorbate at a wild-type level under high light; however, when the pad2 mutation was combined with ∆dhar, there was near complete inhibition of high light-dependent ascorbate accumulation. The lack of ascorbate accumulation was consistent with a marked increase in the ascorbate degradation product threonate. These findings indicate that ascorbate recycling capacity is limited in ∆dhar pad2 plants, and that both DHAR activity and GSH content set a threshold for high light-induced ascorbate accumulation. copyright, serif 2020 American Society of Plant Biologists. All rights reserved.Heat stress (HS) has serious effects on plant development, resulting in heavy agricultural losses. A critical transcription factor network is involved in plant adaptation to high temperature. DEHYDRATION RESPONSIVE ELEMENT-BINDING PROTEIN 2A (DREB2A) is a key transcription factor that functions in plant thermotolerance. The DREB2A protein is unstable under normal temperature and is degraded by the 26S proteasome; however, the mechanism by which DREB2A protein stability dramatically increases in response to HS remains poorly understood. In this study, we found that the DREB2A protein is stabilized under high temperature by the post-translational modification SUMOylation. Biochemical data indicated that DREB2A is SUMOylated at K163, a conserved residue adjacent to the negative regulatory domain (NRD) during HS. SUMOylation of DREB2A suppresses its interaction with BPM2, a ubiquitin ligase component, consequently increasing DREB2A protein stability under high temperature. In addition, analysis of plant heat tolerance and marker gene expression indicated that DREB2A SUMOylation is essential for its function in the HS response. Collectively, our data reveal a role for SUMOylation in the maintenance of DREB2A stability under high temperature, thus improving our understanding of the regulatory mechanisms underlying HS response in plant cell