Isoprene synthesis protects transgenic tobacco plants from oxidative stress.
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.
Vickers
Claudia E
CE
Department of Biological Sciences, Essex University, Wivenhoe Park, Colchester, England C043SQ, UK. c.vickers@uq.edu.au
Possell
Malcolm
M
Cojocariu
Cristian I
CI
Velikova
Violeta B
VB
Laothawornkitkul
Jullada
J
Ryan
Annette
A
Mullineaux
Philip M
PM
Nicholas Hewitt
C
C
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*
D000975:Antioxidants; D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; D017382:Reactive Oxygen Species; C005059:isoprene; D010126:Ozone