The role of thiol-redox protein modifications in ROS-dependent metabolic reprogramming during germination suppression in wheat seeds

A. V., Pabasari Sachinthana (2023) The role of thiol-redox protein modifications in ROS-dependent metabolic reprogramming during germination suppression in wheat seeds. Masters thesis, Memorial University of Newfoundland.

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Pre-harvest sprouting (PHS) is a recurring problem for wheat growers worldwide. However, the molecular mechanisms underlying PHS remain elusive. Redox changes in seed tissues and reactive oxygen species-based triggers are essential for seed germination, with plant NADPH oxidases (NOXs) playing an important role. This study demonstrated the link between ROS production, cellular oxidative metabolism, and sensitivity to external ABA in white-seeded spring wheat. In this study, pharmacological treatments using Diphenylene iodonium (DPI), an inhibitor of NOXs, abscisic acid (ABA) phytohormone, and their combination were used to inhibit germination in freshly harvested (FH) and after-ripened (AR) wheat seeds from doubled haploid (DH) lines with non-dormant genotype. Changes to embryo and aleurone thiol-redoxomes during germination suppression were identified and quantified using iodoTMT labeling, nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS) analysis in conjunction with IWGSC RefSeq and EST wheat databases. The thiol-redoxomes were studied using two different approaches, analyzing changes in reversibly modified proteins (RMPs) (approach I) and in Cys-containing differentially abundant proteins (CysDAPs) (approach II). FH wheat seeds showed higher germination resistance (GR) response to ABA treatment in the presence of DPI as compared to AR seeds. In FH tissues, all RMPs were up-regulated in the reduction level, and most CysDAPs increased in abundance during ABA-mediated germination inhibition under oxidative stress. Most thiol-responsive proteins in FH embryos were involved in cellular respiration, protein biosynthesis and lipid metabolism. High number of storage- and pathogen-responsive proteins were identified in FH aleurones. In contrast to FH tissues, AR tissues contained a minimal amount of RMPs and CysDAPs.

Item Type: Thesis (Masters)
Item ID: 16366
Additional Information: Includes bibliographical references (pages 202-255)
Keywords: pre-harvest sprouting, ROS, NADPH oxidases, post-translational thiol modifications, thiol-redoxome, germination suppression, Triticum aestivum L.
Department(s): Science, Faculty of > Biology
Date: December 2023
Date Type: Submission
Digital Object Identifier (DOI):
Library of Congress Subject Heading: Thiols; Oxidation-reduction reaction; Wheat--Seeds; Wheat-- Preharvest sprouting; Seed technology

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