Chloroplasts are the sites of photosynthesis in plants and algae and, by extension, are essential for most life on Earth. Their maintenance is costly and complex due to the inherent photo-oxidative damage incurred by photosynthetic chemistry. Chloroplast degradation and cell death are mechanisms by which plants acclimate to such stress and serve a dual purpose: protecting cells and organs by removing reactive oxygen species-producing chloroplasts and redistributing nutrients to other tissues. Here I review recent progress in understanding the molecular mechanisms initiating and facilitating such degradation and show these are complex processes involving multiple pathways. Due to the links to photosynthesis and nitrogen metabolism, there is great potential to manipulate these pathways to increase crop yield and quality under stressful environments.
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http://dx.doi.org/10.1016/j.tibs.2022.03.010 | 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 PDFFront Plant Sci
January 2025
Department of Life Science and Technology, Institute of Science Tokyo, Yokohama, Japan.
To enhance plant biomass production under low nitrogen conditions, we employed a method to artificially and temporarily accumulate the bacterial second messenger, guanosine tetraphosphate (ppGpp), to modify plastidial or mitochondrial metabolism. Specifically, we fused a chloroplast or mitochondrial transit-peptide to the N-terminus of the bacterial ppGpp synthase YjbM, which was conditionally expressed by an estrogen-inducible promoter in . The resulting recombinant plants exhibited estrogen-dependent ppGpp accumulation in chloroplasts or mitochondria and showed reduced fresh weight compared to wild type (WT) plants when grown on agar-solidified plates containing a certain amount of estrogen.
View Article and Find Full Text PDFPhysiol Plant
January 2025
Laboratory of Biochemistry, Institut Químic de Sarrià, Universitat Ramon Llull, Barcelona, Spain.
Photosynthetic microalgae are promising green cell factories for the sustainable production of high-value chemicals and biopharmaceuticals. The chloroplast organelle is being developed as a chassis for synthetic biology as it contains its own genome (the plastome) and some interesting advantages, such as high recombinant protein titers and a diverse and dynamic metabolism. However, chloroplast engineering is currently hampered by the lack of standardized cloning tools and Design-Build-Test-Learn workflows to ease genomic and metabolic engineering.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2025
Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115.
The cytoplasmic membrane of bacteria is composed of a phospholipid bilayer made up of a diverse set of lipids. Phosphatidylglycerol (PG) is one of the principal constituents and its production is essential for growth in many bacteria. All the enzymes required for PG biogenesis in have been identified and characterized decades ago.
View Article and Find Full Text PDFTree Physiol
January 2025
State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Lab of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, School of Life Sciences, Nanjing Forestry University, Nanjing 210037, China.
Culm sheaths are capable of photosynthesis and are an important class of non-leaf organs in bamboo plants. The source-sink interaction mechanism has been found to play an important role in the interaction between culm sheaths and internodes in Bambusa multiplex. Research on the regulatory mechanisms of culm sheath senescence is important for the study of internode growth, but reports in this regard are limited.
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