title: Isoprene synthesis protects transgenic tobacco plants from oxidative stress.
abstract: Isoprene emission represents a significant loss of carbon to those plant species that synthesize this highly volatile and reactive compound. As a tool for studying the role of isoprene in plant physiology and biochemistry, we developed transgenic tobacco plants capable of emitting isoprene in a similar manner to and at rates comparable to a naturally emitting species. Thermotolerance of photosynthesis against transient high-temperature episodes could only be observed in lines emitting high levels of isoprene; the effect was very mild and could only be identified over repetitive stress events. However, isoprene-emitting plants were highly resistant to ozone-induced oxidative damage compared with their non-emitting azygous controls. In ozone-treated plants, accumulation of toxic reactive oxygen species (ROS) was inhibited, and antioxidant levels were higher. Isoprene-emitting plants showed remarkably decreased foliar damage and higher rates of photosynthesis compared to non-emitting plants immediately following oxidative stress events. An inhibition of hydrogen peroxide accumulation in isoprene-emitting plants may stall the programmed cell death response which would otherwise lead to foliar necrosis. These results demonstrate that endogenously produced isoprene provides protection from oxidative damage.
authors.affiliation: Department of Biological Sciences, Essex University, Wivenhoe Park, Colchester, England C043SQ, UK. c.vickers@uq.edu.au
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Vickers
authors.forename: Malcolm
authors.initials: M
authors.lastname: Possell
authors.forename: Cristian I
authors.initials: CI
authors.lastname: Cojocariu
authors.forename: Violeta B
authors.initials: VB
authors.lastname: Velikova
authors.forename: Jullada
authors.initials: J
authors.lastname: Laothawornkitkul
authors.forename: Annette
authors.initials: A
authors.lastname: Ryan
authors.forename: Philip M
authors.initials: PM
authors.lastname: Mullineaux
authors.forename: C
authors.initials: C
authors.lastname: Nicholas Hewitt
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002070:Butadienes; D045782:Hemiterpenes / Q000096:biosynthesis*; D006358:Hot Temperature; D018384:Oxidative Stress; D010126:Ozone / Q000494:pharmacology; D010420:Pentanes; D010788:Photosynthesis; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; D017382:Reactive Oxygen Species; C005059:isoprene; D010126:Ozone