Role of reactive oxygen species and antioxidants in plant disease resistance

Abstract

Membrane damage caused by the non-specific fungal toxin fusaric acid was less on pretreated than on control leaves when tobacco leaves were pretreated with anti-senescence plant hormones, such as kinetin, benzyladenine or the anti-ozonant N-[2-(2-oxo-1-imidazolidinyl)]ethyl-N'-phenylurea. Similarly, the necrosis caused by mercuric chloride was reduced by the above anti-senescence agents. In addition, in in vitro tests, leaves from selected paraquat-tolerant tobacco plants were less sensitive to Alternaria alternata (Fr) Keissler infection than those of the control paraquat-sensitive tobacco leaves. Paraquat-tolerant Conyza canadensis (L) Cronq weeds naturally selected in vineyards in Hungary showed similar inhibition of senescence to paraquat-tolerant tobacco, expressed as more green leaves and slower development. In accordance with this, the paraquat-tolerant Conyza leaves remained almost symptomless, while paraquat-sensitive plants showed severe symptoms after infection with Botrytis cinerea Pers. Oxidative burst (accumulation of hydrogen peroxide) was attenuated in TMV-infected leaves of Xanthi-nc tobacco as a result of treatment with salicylic acid or in leaves where systemic acquired resistance (SAR) had been induced by a previous TMV infection. Accordingly, superoxide dismutase (SOD) activity was higher in Xanthi tobacco leaves with SAR than without SAR. However, in NahG tobacco, in which SAR cannot develop, there was no augmentation of SOD activity. All the above data support the significance of delayed senescence and antioxidants in the resistance of plants to biotic and abiotic necrosis-inducing agents.

Superoxide dismutase responses of strawberry cultivars to infection by Mycosphaerella fragariae

“…They play a key role in protecting cells against the toxic effects of superoxide radicals. SODs catalyze the dismutation of O À 2Á produced in different cellular compartments (Fridovich, 1986;Elstner, 1991;Del Rio et al, 2002) by different factors including pathogen attack (Borden and Higgins, 2002;Barna et al, 2003), into H 2 O 2 and O 2 . The hydrogen peroxide produced is then scavenged by other enzymes to water and oxygen.…”

Oxidative stress and antioxidative responses in plant–virus interactions

“…The accumulation of ROS and the resulting oxidative stress in plants elicited by pathogenic microorganisms, mostly bacterial and fungal pathogens, has been the subject of several outstanding reviews [12,14,89,90,146,147]. Therefore, we intend to provide only a brief summary here on the general roles of ROS and oxidative stress in plant defence responses to pathogenic infections.…”

Application of salicylic acid induces antioxidant defense responses in the phloem of Picea abies and inhibits colonization by Ips typographus

“…An antioxidant defense system is generally linked to the actions of reactive oxygen species and is determined by the pool size of the antioxidants (Noctor et al, 2002;Barna et al, 2003;Foyer and Noctor, 2005;Noctor, 2006). Among antioxidants, glutathione is a low-molecular sulfur metabolite, which performs multiple roles in tree-environment interactions and defense Tausz et al, 2004;Tausz, 2007;Zhao et al, 2008).…”