The role of a cytosolic superoxide dismutase in barley-pathogen interactions
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Reactive oxygen species (ROS), including superoxide (O2 .- /HO2 . ) and hydrogen peroxide (H2 O2 ), are differentially produced during resistance responses to biotrophic pathogens and during susceptible responses to necrotrophic and hemi-biotrophic pathogens. Superoxide dismutase (SOD) is responsible for catalysing the dismutation of O2 .- /HO2 . to H2 O2 regulating the redox status of plant cells. Increased SOD activity has been previously correlated with resistance in barley to the hemi-biotrophic pathogen Pyrenophora teres f. teres (Ptt, the causal agent of net form of net blotch disease) but the role of individual isoforms of SOD has not been studied. A cytosolic CuZnSOD, HvCSD1, was isolated from barley and characterised as being expressed in tissue from different developmental stages. HvCSD1 was upregulated during the interaction with Ptt and to a greater extent during the resistance response. Net blotch disease symptoms and fungal growth were not as pronounced in transgenic HvCSD1 knockdown lines in a susceptible background (cv. Golden Promise), as compared to wild type plants, suggesting that cytosolic O2 .- /HO2 . contributes to the signalling required to induce a defence response to Ptt. There was no effect of HvCSD1 knockdown on infection by the hemi-biotrophic rice blast pathogen Magnaporthe oryzae or the biotrophic powdery mildew pathogen, Blumeria graminis f. sp. hordei but HvCSD1 also played a role in the regulation of lesion development by methyl viologen. Together these results suggest that HvCSD1 could be important in maintaining cytosolic redox status and in the differential regulation of responses to pathogens with different lifestyles.
Journal Title/Title of Proceedings
Molecular Plant Pathology
Copyright © 2016 BSPP AND JOHN WILEY & SONS LTD This is the accepted version of the above article, which has been published in final form at http://dx.doi.org/10.1111/mpp.12399