The amyloplast is a specialized plastid in rice endosperm cells where starch is synthesized and stored as starch granules (SGs). However, little is known about the molecular mechanism underlying amyloplast and SG development. In this study, a novel mutant (c134) demonstrating a floury endosperm with enlarged SGs and amyloplasts was identified. The floury endosperm was caused by rounder, loosely packed SG. Grain-quality profile and expression analysis showed reduced contents of total starch and amylose in the c134 mutant, as well as reduced expression of a number of genes involved in starch biosynthesis. Galactosyldiacylglycerol (GDG) content and fatty acid synthesis play important roles in plastid development, and in the c134 endosperm, an obvious decrease in GDG and various fatty acids was observed, with down-regulated expression of various genes involved in lipid biosynthesis. Furthermore, map-based cloning revealed an amino acid substitution (glycine to aspartic acid) in the substandard starch grain4 (SSG4) protein. The results of this study suggest that SSG4 influences the regulation of starch and lipid metabolism as well as amyloplast development, a finding that is useful for potential genetic improvement of rice grain quality in future starch and lipid breeding and biotechnology.
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http://dx.doi.org/10.1016/j.jplph.2022.153638 | DOI Listing |
Physiol Plant
January 2025
Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary.
Investigating the effects of drought stress and subsequent recovery on the structure and function of chloroplasts is essential to understanding how plants adapt to environmental stressors. We investigated Ctenanthe setosa (Roscoe) Eichler, an ornamental plant that can tolerate prolonged drought periods (40 and 49 days of water withdrawal). Conventional biochemical, biophysical, physiological and (ultra)structural methods combined for the first time in a higher plant with in vivo small-angle neutron scattering (SANS) were used to characterize the alterations induced by drought stress and subsequent recovery.
View Article and Find Full Text PDFFunct Integr Genomics
January 2025
Department of Botany, Maharshi Dayanand University, Rohtak, 124001, India.
Despite years of progress in biotechnology, altering the genetic makeup of many plant species, especially their plastids, remains challenging. The existence of a cell wall poses a significant obstacle to the effectual transportation of biomolecules. Developing efficient methods to introduce genes into plant cells and organelles without causing harm is an ongoing area of research.
View Article and Find Full Text PDFPlant Cell Rep
January 2025
Department of Plant Biology and Biotechnology, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, al. Mickiewicza 21, 31-120, Krakow, Poland.
Carrot callus grown on a medium with increased nitrogen have reduced carotenoid accumulation, changed gene expression, high amount of vesicular plastids and altered cell wall composition. Carotenoid biosynthesis is vital for plant development and quality, yet its regulation under varying nutrient conditions remains unclear. To explore the effects of nitrogen (N) availability, we used carrot (Daucus carota L.
View Article and Find Full Text PDFPhotosynthetica
January 2025
College of Life Science, Northwest Normal University, 730070 Lanzhou, China.
This study aimed to explore the mechanism by which Zn retards Fe toxicity by analyzing the morphological, photosynthetic, and chloroplast physiological parameters of wheat seedlings treated with either single or combined Zn and Fe. Different behavior of the seedlings was observed under untreated and treated conditions. The most discriminating quantitative traits were associated with leaf area, biomass dry mass and fresh mass, net photosynthetic rate, intercellular CO concentration, stomatal conductance, transpiration rate of seedlings, Hill reaction, Mg-ATPase and Ca-ATPase activities, malondialdehyde and O contents, and glutathione reductase, ascorbate peroxidase, peroxidase, and superoxide dismutase activities and their gene expression in the seedling chloroplast.
View Article and Find Full Text PDFNat Commun
January 2025
Molecular Genetics of Eukaryotes, University of Kaiserslautern, Kaiserslautern, Germany.
Molecular chaperones are essential throughout a protein's life and act already during protein synthesis. Bacteria and chloroplasts of plant cells share the ribosome-associated chaperone trigger factor (Tig1 in plastids), facilitating maturation of emerging nascent polypeptides. While typical trigger factor chaperones employ three domains for their task, the here described truncated form, Tig2, contains just the ribosome binding domain.
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