Investigating a key plant stress tolerance protein
Stresses such as drought, high salt and high temperatures cause cellular damage and death in plants via the increased production of reactive oxygen species (ROS). An enzyme in T. halophila, plastid terminal oxidase (PTOX), has recently been identified as being able to 'mop up' ROS before they can damage the plant. Scientists refer to this kind of enzyme as an electron sink. An EU-funded research project called 'The role and functioning of the PTOX in stress tolerance in extremophile Thelungiella halophila' (FUNCPTOXTHELL) was established to investigate this enzyme in more detail. In particular, the researchers aimed to use PTOX to confer stress tolerance to other plants. They investigated the regulation of PTOX in the cell to find out how it works as an electron sink. Project plans included engineering PTOX into a different plant species to investigate whether it would improve the stress tolerance in other plants, such as crops. On its own, PTOX could not improve stress tolerance in other plants, suggesting that other factors are involved. Further work showed that PTOX interacted with several proteins involved in photosynthesis, and that these were found in the same parts of the cell when the plants were exposed to stress. Another important finding was that the function of PTOX differed in response to different types of stress. PTOX is known to be a key enzyme in stress tolerance in T. halophila, and this research expanded knowledge of the underlying mechanisms. The research will also form a substantial information base for engineering other stress-tolerant plants.
