Does alternative oxidase play a role in plant adaptation to anoxia and post-anoxia?

Jayawardhane, Jayamini (2019) Does alternative oxidase play a role in plant adaptation to anoxia and post-anoxia? Masters thesis, Memorial University of Newfoundland.

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Low oxygen stress and reaeration have detrimental effects on plants. Transgenic tobacco plants differentially expressing alternative oxidase (AOX) were used to investigate its role during anoxia and post-anoxia. Superoxide, hydrogen peroxide and malondialdehyde (MDA) levels increased under anoxia and post-anoxia exhibiting lower level in AOX-overexpressing lines. Nitric oxide (NO) emission increased during anoxia stronger in overexpressing lines while nitrosylation of proteins followed a reverse pattern. ATP/ADP ratio decreased during anoxia and increased with reaeration being higher in overexpressing lines. Alcohol dehydrogenase and aconitase increased during anoxia and decreased during post-anoxia in overexpressing lines. AOX-knockdown lines had higher SOD and lower catalase activity than overexpressors. The activities of enzymes of ascorbate-glutathione cycle decreased during both conditions being higher in overexpressing lines. We conclude that AOX is involved in NO turnover and plays a protective role by reducing the level of reactive oxygen species and sustaining energy requirements during anoxia and post-anoxia.

Item Type: Thesis (Masters)
Item ID: 14328
Additional Information: Includes bibliographical references (pages 68-96).
Department(s): Science, Faculty of > Biology
Date: December 2019
Date Type: Submission
Digital Object Identifier (DOI):
Library of Congress Subject Heading: Plants--Effect of oxygen on; Oxidases.

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