Energy production by chloroplasts and mitochondria causes constant oxidative damage. A functioning photosynthetic cell requires quality-control mechanisms to turn over and degrade chloroplasts damaged by reactive oxygen species (ROS). Here, we generated a conditionally lethal Arabidopsis mutant that accumulated excess protoporphyrin IX in the chloroplast and produced singlet oxygen. Damaged chloroplasts were subsequently ubiquitinated and selectively degraded. A genetic screen identified the plant U-box 4 (PUB4) E3 ubiquitin ligase as being necessary for this process. pub4-6 mutants had defects in stress adaptation and longevity. Thus, we have identified a signal that leads to the targeted removal of ROS-overproducing chloroplasts.
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http://dx.doi.org/10.1126/science.aac7444 | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
Molecular Genetics, Institute of Biology, Faculty of Life Sciences, Humboldt Universität zu Berlin, Berlin 10115, Germany.
The chloroplast genome encodes key components of the photosynthetic light reaction machinery as well as the large subunit of the enzyme central for carbon fixation, Ribulose-1,5-bisphosphat-carboxylase/-oxygenase (RuBisCo). Its expression is predominantly regulated posttranscriptionally, with nuclear-encoded RNA-binding proteins (RBPs) playing a key role. Mutants of chloroplast gene expression factors often exhibit impaired chloroplast biogenesis, especially in cold conditions.
View Article and Find Full Text PDFPlant Physiol Biochem
January 2025
Plant Sciences and Agrotechnology Division, Indian Institute of Integrative Medicine (CSIR), Canal Road, Jammu, J & K, 180001, India; Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India. Electronic address:
Transplantation experiments conducted in high altitude ecosystems are rising as key strategy to examine the response of individual plant transplanted across distinct elevations. However, plant physiological and biochemical performance in response to changes in abiotic factors across different species and mountain ranges is still lacking. So in the present study, we have made an attempt to link the physiological performance with that of altitudinal gradient in Ladakh by transplanting Lepidium latifolium at four different altitudinal sites.
View Article and Find Full Text PDFPhysiol Plant
January 2025
College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, China.
The gene GAD1 encodes a glutamate decarboxylase, which is a rate-limiting enzyme for the biosynthesis of endogenous γ-aminobutyrate acid (GABA), but a potential role of GAD1 in regulating cadmium (Cd) tolerance needs to be further elucidated in plants. The objective of this study was to investigate Cd tolerance of creeping bentgrass (Agrostis stolonifera) and transgenic yeast (Saccharomyces cerevisiae) or Arabidopsis thaliana overexpressing AsGAD1. The Cd-tolerant creeping bentgrass cultivar LOFTSL-93 accumulated more endogenous GABA in relation to a significant upregulation of AsGAD1 in leaf and root than the Cd-sensitive W66569 in response to Cd stress.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Department of Agronomy, Zhejiang University, Hangzhou 310058, China.
Heat stress is one of the major concerns for wheat production worldwide. Morphological parameters such as germination, leaf area, shoot, and root growth are affected by heat stress, with affected physiological parameters including photosynthesis, respiration, and water relation. Heat stress also leads to the generation of reactive oxygen species that disrupt the membrane systems of thylakoids, chloroplasts, and the plasma membrane.
View Article and Find Full Text PDFJ Environ Sci (China)
July 2025
School of Environmental Science and Engineering, Shandong Key Laboratory of Environmental Processes and Health, Shandong University, Qingdao 266237, China; Laboratory of Marine Ecological Environment in Universities of Shandong, Shandong University, Qingdao 266237, China; Qingdao Key Laboratory of Marine Pollutant Prevention, Shandong University, Qingdao 266237, China; Shandong Kenli Petrochemical Group Co., Ltd., Dongying 257500, China. Electronic address:
Due to the endocrine toxicity, neurotoxic, and reproductive toxicity to organisms, the sources and risks of brominated organic pollutants have attracted widespread attention. However, knowledge gaps remain in the bromination processes of emerging phenolic pollutants in plants, which may increase the potential health risk associated with food exposure. Our study discovered that light induced generation and accumulation of more toxic brominated organic compounds (Br-org) in lettuce leaves under the stress of acetaminophen (ACE) than that without light, as evidenced by an increase in C-Br bond intensity in FTIR analysis.
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