title: Transient Influx of nickel in root mitochondria modulates organic acid and reactive oxygen species production in nickel hyperaccumulator Alyssum murale.
abstract: Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation.
authors: Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, USA.
authors: Bhavana
authors: B
authors: Agrawal
authors: Kirk J
authors: KJ
authors: Czymmek
authors: Donald L
authors: DL
authors: Sparks
authors: Harsh P
authors: HP
authors: Bais
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport; D019607:Brassicaceae / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002264:Carboxylic Acids / Q000378:metabolism*; D019343:Citric Acid / Q000378:metabolism; D002952:Citric Acid Cycle / Q000187:drug effects; D006706:Homeostasis; D008293:Malates / Q000378:metabolism; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D008954:Models, Biological; D009532:Nickel / Q000378:metabolism* / Q000494:pharmacology; D027361:Organic Anion Transporters / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013045:Species Specificity; D013997:Time Factors; D014617:Vacuoles / Q000378:metabolism
chemical_list: C512361:ALMT1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002264:Carboxylic Acids; D008293:Malates; D027361:Organic Anion Transporters; D017382:Reactive Oxygen Species; D019343:Citric Acid; D009532:Nickel; C030298:malic acid