title: Toxicity of canavanine in tomato (Solanum lycopersicum L.) roots is due to alterations in RNS, ROS and auxin levels.
abstract: Canavanine (CAN) is non-proteinogenic aminoacid and a structural analog of arginine (Arg). Naturally, CAN occurs in legumes e.g. jack bean and is considered as a strong allelochemical. As a selective inhibitor of inducible nitric oxide synthase in mammalians, it could act as a modifier of nitric oxide (NO) concentration in plants. Modifications in the content of endogenous reactive nitrogen species (RNS) and reactive oxygen species (ROS) influence root structure and architecture, being also under hormonal control. The aim of the work was to investigate regulation of root growth in tomato (Solanum lycopersicum L. cv. Malinowy Ożarowski) seedling by application of CAN at concentration (10 and 50 μM) leading to 50% or 100% restriction of root elongation. CAN at higher concentration led to slight DNA fragmentation, increased total RNA and protein level. Decline in total respiration rate after CAN supplementation was not associated with enhanced membrane permeability. Malformations in root morphology (shorter and thicker roots, limited number of lateral roots) were accompanied by modification in NO and ONOO(-) localization; determined mainly in peridermal cells and some border cells. Although, CAN resulted in low RNS production, addition of exogenous NO by usage of NO donors did not reverse its negative effect, nor recovery effect was detected after roots imbibition in Arg. To build up a comprehensive view on mode of action of CAN as root growth inhibitor, it was shown an elevated level of auxin. To summarize, we demonstrated several secondary mode of action of CAN, indicating its toxicity in plants linked to restriction in RNS formation accompanied by simultaneous overaccumulation of ROS.
authors.affiliation: Department of Plant Physiology, Poland. Electronic address: urszula_krasuska@sggw.pl.
authors.forename: Urszula
authors.initials: U
authors.lastname: Krasuska
authors.affiliation: Department of Plant Physiology, Poland. Electronic address: andrzejczakolga5@gmail.com.
authors.forename: Olga
authors.initials: O
authors.lastname: Andrzejczak
authors.affiliation: Department of Plant Physiology, Poland. Electronic address: pawel.e.staszek@gmail.com.
authors.forename: Paweł
authors.initials: P
authors.lastname: Staszek
authors.affiliation: Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska Str. 159, 02-776 Warsaw, Poland. Electronic address: wojciech_borucki@sggw.pl.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Borucki
authors.affiliation: Department of Plant Physiology, Poland. Electronic address: agnieszka_gniazdowska@sggw.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Gniazdowska
mesh_terms: D002172:Canavanine / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D007210:Indoleacetic Acids / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000494:pharmacology; D020030:Nitric Oxide Donors / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects / Q000502:physiology
chemical_list: D007210:Indoleacetic Acids; D020030:Nitric Oxide Donors; D010937:Plant Growth Regulators; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D002172:Canavanine; D010100:Oxygen
keywords: Canavanine; Cell viability; DNA fragmentation; Non-protein amino acid; Phytotoxicity; RNS; ROS