Analysis of oxidative signalling induced by ozone in Arabidopsis thaliana

Abstract

We are using acute ozone as an elicitor of endogenous reactive oxygen species (ROS) to understand oxidative signalling in Arabidopsis . Temporal patterns of ROS following a 6 h exposure to 300 nL L -1 of ozone in ozone-sensitive Wassilewskija (Ws-0) ecotype showed a biphasic ROS burst with a smaller peak at 4 h and a larger peak at 16 h. This was accompanied by a nitric oxide (NO) burst that peaked at 9 h. An analysis of antioxidant levels showed that both ascorbate (AsA) and glutathione (GSH) were at their lowest levels, when ROS levels were high in ozone-stressed plants. Whole genome expression profiling analysis at 1, 4, 8, 12 and 24 h after initiation of ozone treatment identified 371 differentially expressed genes. Early induction of proteolysis and hormone-responsive genes indicated that an oxidative cell death pathway was triggered rapidly. Downregulation of genes involved in carbon utilization, energy pathways and signalling suggested an inefficient defense response. Comparisons with other large-scale expression profiling studies indicated some overlap between genes induced by ethylene and ozone, and a significant overlap between genes repressed by ozone and methyl jasmonate treatment. Further, analysis of cis elements in the promoters of ozone-responsive genes also supports the view that phytohormones play a significant role in ozone-induced cell death.

The physiological, transcriptional and genetic responses of an ozone- sensitive and an ozone tolerant poplar and selected extremes of their F 2 progeny

“…Stomata regulate the entry of ozone into the leaf (Vahisalu et al, 2008), and when ozone reaches the apoplast, production of toxic reactive oxygen species (ROS) is initiated (Mahalingam et al, 2006;Wohlgemuth et al, 2002). Symptoms range from accelerated senescence (Karnosky et al, 1996) and a decrease in growth rate (Karnosky et al, 1996Wittig et al, 2009), to foliar injury manifested as necrotic lesions analogous to those formed during the hypersensitive response (HR) .…”

Visible injury and nitrogen metabolism of rice leaves under ozone stress, and effect on sugar and protein contents in grain

“…Many researches report that ozone stress may affect the activity of enzymes in plant antioxidant system (Mahalingam et al, 2006;Iriti and Faoro, 2008;Esposito et al, 2009) and the contents of non-enzyme materials (Holopainen and Kainulainen, 1997;Conklin and Barth, 2004;Singh et al, 2010), causing serious injury (Pina and Moraes, 2010;Sarkar and Agrawal, 2010). Ozone stress has great influence on the production of crops, and may cause a reduction in crop production of 5e15%, or over 20% in some crops (Cho et al, 2011).…”

Copper-induced calcium release from ER involves the activation of ryanodine-sensitive and IP3-sensitive channels inUlva compressa

“…1,2 Regarding abiotic stress, it has been shown that ozone triggers a NADPH oxidase-dependent biphasic oxidative burst in Arabidopsis thaliana that activates antioxidant and defense enzymes. 3,4 In addition, cadmium induced a NADPH oxidase-dependent monophasic accumulation of extracellular hydrogen peroxide in tobacco cells. 5 On the other hand, ozone as well as absicic acid treatment, dessication, cold, heat, salinity, UV light and anoxia induce intracellular calcium release and the activation of antioxidant enzymes.…”