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Functional analysis of polyphenol oxidases by antisense/sense technology
Piyada Thipyapong1, Michael J Stout, Jutharat Attajarusit
1Suranaree University of Technology, 111 University Ave., Muang District, Nakhon Ratchasima 30000, Thailand. piyada@sut.ac.th
Molecules (Basel, Switzerland)
|October 26, 2007
Summary
Polyphenol oxidases (PPOs) play a crucial role in plant defense against diseases and insects. Manipulating PPO activity in tomato plants can enhance resistance to pests and pathogens while also impacting water stress and photoinhibition.
Area of Science:
- Plant Science
- Biochemistry
- Molecular Biology
Background:
- Polyphenol oxidases (PPOs) are enzymes involved in oxidative browning and postharvest losses in fruits and vegetables.
- PPOs are inducible by stresses and play roles in plant defense, Mehler reaction, and other physiological processes.
Purpose of the Study:
- To investigate the roles of PPO in disease and insect resistance using transgenic tomato plants.
- To explore the effects of modified PPO expression on plant physiology, including water relations and photoinhibition.
Main Methods:
- Generation of transgenic tomato (Lycopersicon esculentum) plants with suppressed and overexpressed PPO.
- Assessment of plant resistance to Pseudomonas syringae and various insect pests (e.g., Spodoptera litura, Helicoverpa armigera).
- Evaluation of water relations and photoinhibition in transgenic plants.
Main Results:
- PPO overexpression increased resistance to Pseudomonas syringae and insect pests, while suppressed PPO increased susceptibility.
- Insects feeding on suppressed PPO plants showed higher growth rates and foliage consumption.
- Suppressed PPO plants exhibited improved water relations and decreased photoinhibition compared to controls and overexpressing plants.
Conclusions:
- PPO plays a significant defensive role in plants against pathogens and insects.
- Manipulation of PPO activity offers potential for broad-spectrum resistance in crops.
- Consideration of PPO's effects on postharvest quality and water stress physiology is crucial for commercial applications.
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