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Updated: May 19, 2026
04:54
Efficient Polyethylene Glycol (PEG) Mediated Transformation of the Moss Physcomitrella patens
Published on: April 19, 2011
Polyphenol oxidases in Physcomitrella: functional PPO1 knockout modulates cytokinin-dependent development in the moss
Hanna Richter1, Reinhard Lieberei, Miroslav Strnad
1University of Hamburg, Biozentrum Klein Flottbek, Ohnhorststraße 18, D-22609 Hamburg, Germany.
Journal of Experimental Botany
|August 7, 2012
Summary
Polyphenol oxidases (PPOs) in the early plant Physcomitrella patens have 13 genes. Knockout plants show PPO1 is extracellular and impacts development and stress tolerance.
Area of Science:
- Plant Biology
- Enzymology
- Evolutionary Biology
Background:
- Polyphenol oxidases (PPOs) are crucial copper-binding enzymes in plant secondary metabolism, oxidizing polyphenols to quinones.
- While PPOs are widespread in seed plants, their evolution and function in earlier land plant lineages remain largely unexplored.
Purpose of the Study:
- To investigate the PPO gene family in the moss Physcomitrella patens, an early divergent plant.
- To elucidate the evolutionary history and functional roles of PPOs in non-seed plants.
Main Methods:
- Phylogenetic analysis of the P. patens PPO multigene family (13 paralogues).
- Recombinant expression and characterization of PPO6.
- LC-MS analysis of phenolic compounds in P. patens.
- Generation and analysis of PPO1 knockout (d|ppo1) mutants.
Main Results:
- Phylogenetic analyses indicate PPO evolution coincided with land colonization, with duplications in P. patens occurring post-moss/seed plant divergence.
- Recombinant PPO6 exhibited enzymatic activity. Six phenolic compounds were identified intracellularly.
- d|ppo1 plants showed reduced extracellular PPO activity, suggesting PPO1's extracellular localization, contrasting with seed plant PPOs.
- d|ppo1 mutants displayed altered development (more gametophores, smaller size) and reduced tolerance to 4-methylcatechol, indicating PPO1's role in development and stress response.
Conclusions:
- The P. patens PPO gene family comprises 13 members, with duplications specific to the moss lineage.
- Extracellular PPO1 plays a significant role in plant development and in mitigating phenolic compound toxicity, suggesting a role in establishing favorable extracellular conditions.
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