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Doctoral thesis, 2009

Active oxygen involvement in developmental processes in Populus

Srivastava, Vaibhav


In plants, oxidative stress is result of disruption of the cellular redox metabolism and is caused by a variety of stress conditions (abiotic and/or biotic). This leads to the induction of several mechanisms that protect against disruption of the redox balance, as well as mechanisms to assist in recovery from toxicity/damage caused by increased cellular levels of reactive oxygen species (ROS). The superoxide dismutase enzymes (SODs) are key component of the reactive oxygen species gene network and represent the first line of defense against ROS, by converting superoxide radicals (O2−) to hydrogen peroxide (H2O2) and water (H2O). Therefore, SODs play an important role in protection against oxidative stress in all aerobic organisms. In this thesis, I describe the characterization of an SOD isoform from Populus, hipI-SOD, which has a high iso-electric point. The global response to oxidative stress is also discussed. Different forms of hipI-SOD transcripts were found in vascular tissue, one of which was produced by alternative splicing. HipI-SOD proteins were found to be mainly localized extracellularly, in the primary and secondary cell walls of vascular tissues. These results together with analysis of transgenic Populus trees with suppressed expression of hipI-SOD strongly indicate roles for hipI-SOD in regulating ROS levels in vascular tissue. ROS are important regulators of plant stress responses. Nevertheless, oxidative stress often affects plants growth and development. In order to understand the basis of oxidative stress tolerance, the diversity of stress responses needs to be investigated. To achieve this we first developed an O2PLS-based multivariate methodology for the integration of multiple datasets originating from three different platforms (transcriptomics, proteomics and metabolomics). Subsequently this data integration method was utilized for a comprehensive study of the overall responses to oxidative stress in Populus. The findings may facilitate the development of stress-tolerant plants with improved survival rates and yields under stressed conditions.


populus; superoxide dismutase; vascular tissues; cell walls; oxidation; stress

Published in

Acta Universitatis Agriculturae Sueciae
2009, number: 2009:21
ISBN: 9789186195687
Publisher: Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences

Authors' information

Srivastava, Vaibhav
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology

UKÄ Subject classification

Forest Science

URI (permanent link to this page)