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.  https://www.selleckchem.com/products/kp-457.html  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 cells. copyright, serif 2020 American Society of Plant Biologists. All rights reserved.The selection and firing of DNA replication origins play key roles in ensuring that eukaryotes accurately replicate their genomes. This process is not well documented in plants due in large measure to difficulties in working with plant systems. We developed a new functional assay to label and map very early replicating loci that must, by definition, include at least a subset of replication origins. Arabidopsis thaliana cells were briefly labeled with 5-ethynyl-2'-deoxy-uridine, and nuclei were subjected to two-parameter flow sorting. We identified more than 5500 loci as initiation regions (IRs), the first regions to replicate in very early S phase. These were classified as strong or weak IRs based on the strength of their replication signals. Strong initiation regions were evenly spaced along chromosomal arms and depleted in centromeres, while weak initiation regions were enriched in centromeric regions. IRs are AT-rich sequences flanked by more GC-rich regions and located predominantly in intergenic regions. Nuclease sensitivity assays indicated that IRs are associated with accessible chromatin. Based on these observations, initiation of plant DNA replication shows some similarity to, but is also distinct from, initiation in other well-studied eukaryotic systems. copyright, serif 2020 American Society of Plant Biologists. All rights reserved.Phosphoinositides function as lipid signals in plant development and stress tolerance by binding with partner proteins. We previously reported that Arabidopsis (Arabidopsis thaliana) phosphoinositide-specific phospholipase C2 (PLC2) functions in the endoplasmic reticulum (ER) stress response. However, the underlying molecular mechanisms of how phosphoinositides act in the ER stress response remain elusive. Here, we report that a phosphoinositide-binding protein, SMALLER TRICHOMES WITH VARIABLE BRANCHES (SVB), is involved in the ER stress tolerance. SVB contains a DUF538 domain with unknown function; orthologs are exclusively found in Viridiplantae (green plants). We established that SVB is ubiquitously expressed in plant tissues and is localized to the ER, Golgi apparatus, prevacuolar compartment, and plasma membranes. The knockout mutants of svb showed enhanced tolerance to ER stress, which was genetically complemented by transducing genomic SVB. SVB showed time-dependent induction after tunicamycin-induced ER stress, which depended on IRE1 and bZIP60 but not bZIP17 and bZIP28 in the unfolded protein response (UPR). A protein-lipid overlay assay showed specific binding of SVB to phosphatidylinositol 3,5-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate. SVB is therefore suggested to be the plant-specific phosphoinositide-binding protein whose expression is controlled by the UPR through the IRE1-bZIP60 pathway in Arabidopsis. copyright, serif 2020 American Society of Plant Biologists. All rights reserved.BACKGROUND The addition of hyperthermic intraperitoneal chemotherapy (HIPEC) to interval cytoreductive surgery improves recurrence-free and overall survival in patients with FIGO stage III ovarian cancer who are ineligible for primary cytoreductive surgery. The effect of HIPEC remains undetermined in patients who are candidates for primary cytoreductive surgery. PRIMARY OBJECTIVE The primary objective is to evaluate the effect of HIPEC on overall survival in patients with FIGO stage III epithelial ovarian cancer who are treated with primary cytoreductive surgery resulting in no residual disease, or residual disease up to 2.5 mm in maximum dimension. STUDY HYPOTHESIS We hypothesize that the addition of HIPEC to primary cytoreductive surgery improves overall survival in patients with primary FIGO stage III epithelial ovarian cancer. TRIAL DESIGN This international, randomized, open-label, phase III trial will enroll 538 patients with newly diagnosed FIGO stage III epithelial ovarian cancer. Following complete o trial started in January 2020 and primary analyses are anticipated in 2026. TRIAL REGISTRATION ClinicalTrials.govNCT03772028. © IGCS and ESGO 2020. No commercial re-use. See rights and permissions. Published by BMJ.