1. �-Cyanoalanine Synthase Action in Root Hair Elongation is Exerted at Early Steps of the Root Hair Elongation Pathway and is Independent of Direct Cyanide Inactivation of NADPH Oxidase
- Author
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Cecilia Gotor, Irene García, Lucía Arenas-Alfonseca, Luis C. Romero, and Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular
- Subjects
0106 biological sciences ,0301 basic medicine ,Arabidopsis thaliana ,SCN1 ,Physiology ,Cyanide ,Mutant ,Arabidopsis ,Lyases ,Plant Science ,Root hair ,Root hair elongation ,Models, Biological ,Plant Roots ,01 natural sciences ,Green fluorescent protein ,03 medical and health sciences ,Adenosine Triphosphate ,Gene interaction ,Gene Expression Regulation, Plant ,Superoxides ,Hydroxocobalamin ,RHD2 ,Root Hair ,ß-Cyanoalanine Synthase ,Cysteine Synthase ,Cyanides ,NADPH oxidase ,integumentary system ,biology ,ATP synthase ,Arabidopsis Proteins ,Chemistry ,NADPH Oxidases ,Epistasis, Genetic ,Hydrogen Peroxide ,Cell Biology ,General Medicine ,biology.organism_classification ,Mitochondria ,Cell biology ,Enzyme Activation ,Phenotype ,030104 developmental biology ,Mutation ,biology.protein ,010606 plant biology & botany - Abstract
In Arabidopsis thaliana, cyanide is produced concomitantly with ethylene biosynthesis and is mainly detoxified by the ß-cyanoalanine synthase CAS-C1. In roots, CAS-C1 activity is essential to maintain a low level of cyanide for proper root hair development. Root hair elongation relies on polarized cell expansion at the growing tip, and we have observed that CAS-C1 locates in mitochondria and accumulates in root hair tips during root hair elongation, as shown by observing the fluorescence in plants transformed with the translational construct ProC1:CASC1-GFP, containing the complete CAS-C1 gene fused to GFP. Mutants in the SUPERCENTIPEDE (SCN1) gene, that regulate the NADPH oxidase RHD2/AtrbohC, are affected at the very early steps of the development of root hair that do not elongate and do not show a preferential localization of the GFP accumulation in the tips of the root hair primordia. Root hairs of mutants in CAS-C1 or RHD2/AtrbohC, which catalyzes the generation of ROS and the Ca2+ gradient, correctly start to grow out but they do not elongate either. Genetic crosses between the cas-c1 mutant and scn1 or rhd2 mutants were performed and the detail phenotypic and molecular characterization of the double mutants demonstrate that scn1 mutation is epistatic to cas-c1 and cas-c1 is epistatic to rhd2 mutation, indicating that CAS-C1 acts in early steps of the root hair development process. Moreover, our results show that the role of CAS-C1 in root hair elongation is independent of H2O2 production and of a direct NADPH oxidase inhibition by cyanide
- Published
- 2018
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