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.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (2MB)

Abstract

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.

Actions (login required)

View Item