title: Reactive oxygen species mediate axis-cotyledon signaling to induce reserve mobilization during germination and seedling establishment in Vigna radiata.
abstract: Seeds represent an excellent opportunity to investigate the role of reactive oxygen species (ROS) in control of metabolism during germination and seedling establishment. Cotyledons, the storage organs in Vigna, do not display growth/cell division while the embryonic axis shows rapid growth and intense metabolic activity. The present study investigates the possibility of ROS generated during respiration in the axis serving as messengers guiding storage reserve mobilization from cotyledons at the pre-greening stage. Seeds were germinated in the presence of hydroxyurea to halt cell division in the S-phase and separately in Edaravone, a potent free radical scavenger. Both treatments caused a decrease in germination percentage, seedling growth and protein mobilization. In the growing axis, both treatments resulted in a decrease in hydrogen peroxide (H2O2), total ROS, MDA and protein carbonyls. The picture in cotyledons was quite different, owing to the physiological dissimilarities between the tissues. The status of redox as evident by GSH/GSSG ratios tended toward oxidizing in axis in comparison to the highly reducing environment found in cotyledons. This is construed as a tendency to maintain redox buffering on the oxidizing side in the axis, to facilitate the passage of ROS message. These results strongly indicate that suppression of cell division or scavenging of ROS adversely affects protein reserve mobilization. It is proposed that apart from H2O2 being a transportable signal, the final message perceived in cotyledons also comprises lipid peroxidation, protein carbonylation and alteration of redox status of the glutathione pool.
authors.affiliation: Department of Biochemistry, University of Lucknow, Lucknow 226007, India. Electronic address: gitivermabiochem@gmail.com.
authors.forename: Giti
authors.initials: G
authors.lastname: Verma
authors.affiliation: Plant Diversity, Systematics and Herbarium Division, CSIR-National Botanical Research Institute, Lucknow 226001, India. Electronic address: sujata0608@yahoo.co.in.
authors.forename: Sujata
authors.initials: S
authors.lastname: Mishra
authors.affiliation: Metabolic and Structural Biology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow 226015, India. Electronic address: sangwan.neelam@gmail.com.
authors.forename: Neelam
authors.initials: N
authors.lastname: Sangwan
authors.affiliation: Department of Biochemistry, University of Lucknow, Lucknow 226007, India. Electronic address: samiersharma@gmail.com.
authors.forename: Samir
authors.initials: S
authors.lastname: Sharma
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D000983:Antipyrine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D018548:Cotyledon / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D000077553:Edaravone; D007887:Fabaceae / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D018525:Germination; D006918:Hydroxyurea / Q000494:pharmacology*; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D015398:Signal Transduction
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D000077553:Edaravone; D000983:Antipyrine; D006918:Hydroxyurea
keywords: Edaravone; Hydroxyurea; Protein reserve mobilization; ROS; Seed germination; Vigna radiata