title: Heterologous expression of mitochondria-targeted microbial nitrilase enzymes increases cyanide tolerance in Arabidopsis.
abstract: Anthropogenic activities have resulted in cyanide (CN) contamination of both soil and water in many areas of the globe. While plants possess a detoxification pathway that serves to degrade endogenously generated CN, this system is readily overwhelmed, limiting the use of plants in bioremediation. Genetic engineering of additional CN degradation pathways in plants is one potential strategy to increase their tolerance to CN. Here we show that heterologous expression of microbial nitrilase enzymes targeted to the mitochondria increases CN tolerance in Arabidopsis. Root length in seedlings expressing either a CN dihydratase from Bacillus pumilis or a CN hydratase from Neurospora crassa was increased by 45% relative in wild-type plants in the presence of 50 μm KCN. We also demonstrate that in contrast to its strong inhibitory effects on seedling establishment, seed germination of the Col-0 ecotype of Arabidopsis is unaffected by CN.
authors.affiliation: Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, South Africa.
authors.forename: E
authors.initials: E
authors.lastname: Molojwane
authors.affiliation: Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, South Africa.
authors.forename: N
authors.initials: N
authors.lastname: Adams
authors.affiliation: Department of Plant Sciences, University of Oxford, Oxford, UK.
authors.forename: L J
authors.initials: LJ
authors.lastname: Sweetlove
authors.affiliation: Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, South Africa.
authors.forename: R A
authors.initials: RA
authors.lastname: Ingle
mesh_terms: D000619:Aminohydrolases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003486:Cyanides / Q000633:toxicity*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D018525:Germination; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism*; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology; D009492:Neurospora crassa / Q000201:enzymology* / Q000235:genetics; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D019076:Transgenes
chemical_list: D001426:Bacterial Proteins; D003486:Cyanides; D005656:Fungal Proteins; D006867:Hydrolases; D000619:Aminohydrolases; C083488:cyanide dihydratase; C021867:nitrilase; D006836:Hydro-Lyases; C076848:cyanide hydratase
keywords: Arabidopsis; bioremediation; cyanide; germination; mitochondria; nitrilase