Interaction between nitric oxide and ethylene in the induction of alternative oxidase in ozone-treated tobacco plants.
The higher plant mitochondrial electron transport chain contains, in addition to the cytochrome chain, an alternative pathway that terminates with a single homodimeric protein, the alternative oxidase (AOX). We recorded temporary inhibition of cytochrome capacity respiration and activation of AOX pathway capacity in tobacco plants (Nicotiana tabacum L. cv BelW3) fumigated with ozone (O(3)). The AOX1a gene was used as a molecular probe to investigate its regulation by signal molecules such as hydrogen peroxide, nitric oxide (NO), ethylene (ET), salicylic acid, and jasmonic acid (JA), all of them reported to be involved in the O(3) response. Fumigation leads to accumulation of hydrogen peroxide in mitochondria and early accumulation of NO in leaf tissues. Although ET accumulation was high in leaf tissues 5 h after the start of O(3) fumigation, it declined during the recovery period. There were no differences in the JA and 12-oxo-phytodienoic acid levels of treated and untreated plants. NO, JA, and ET induced AOX1a mRNA accumulation. Using pharmacological inhibition of ET and NO, we demonstrate that both NO- and ET-dependent pathways are required for O(3)-induced up-regulation of AOX1a. However, only NO is indispensable for the activation of AOX1a gene expression.
Ederli
Luisa
L
Department of Plant Biology and Agro-Environmental and Animal Biotechnology, University of Perugia, I-06121 Perugia, Italy.
Morettini
Roberta
R
Borgogni
Andrea
A
Wasternack
Claus
C
Miersch
Otto
O
Reale
Lara
L
Ferranti
Francesco
F
Tosti
Nicola
N
Pasqualini
Stefania
S
D003517:Cyclopentanes / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000378:metabolism*; D010088:Oxidoreductases / Q000096:biosynthesis*; D054883:Oxylipins; D010126:Ozone / Q000494:pharmacology*; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins; D014026:Nicotiana / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects; D000099188:Alternative Oxidase
D003517:Cyclopentanes; D045304:Cytochromes c; D005030:Ethylenes; D006861:Hydrogen Peroxide; D024101:Mitochondrial Proteins; D009569:Nitric Oxide; D010088:Oxidoreductases; D054883:Oxylipins; D010126:Ozone; D010940:Plant Proteins; D000099188:Alternative Oxidase; C011006:jasmonic acid; C036216:ethylene