Pathogenesis-related proteins protect extrafloral nectar from microbial infestation
Marcia González-Teuber1, Sascha Eilmus, Alexander Muck
1Department of General Botany - Plant Ecology, University of Duisburg-Essen, Universitätsstrasse 5, 45117 Essen, Germany.
The Plant Journal : for Cell and Molecular Biology
|January 16, 2009
Summary
Plants use extrafloral nectar (EFN) for defense, but it needs microbial protection. Myrmecophyte EFN has more proteins and stronger antimicrobial activity from pathogenesis-related enzymes, effectively preventing infestation.
Area of Science:
- Plant biology
- Ecology
- Biochemistry
Background:
- Plants produce extrafloral nectar (EFN) to attract beneficial insects for herbivore defense.
- EFN, rich in nutrients, is vulnerable to microbial contamination due to exposed nectaries.
Purpose of the Study:
- To investigate the protein content and antimicrobial activity of EFN in myrmecophytes versus non-myrmecophytes.
- To identify specific proteins and enzymes responsible for EFN's antimicrobial properties.
Main Methods:
- Comparative analysis of EFN from two Central American Acacia myrmecophytes and two non-myrmecophytes.
- Quantification of protein content and assessment of antimicrobial activity using biochemical assays.
- Identification of proteins using nanoLC-MS/MS.
Main Results:
- Myrmecophyte EFN contained significantly higher protein concentrations than non-myrmecophyte EFN.
- EFN from myrmecophytes exhibited potent antimicrobial activity, effectively inhibiting microbial growth.
- Pathogenesis-related (PR) enzymes, including chitinase and beta-1,3-glucanase, were identified as key contributors to EFN's antimicrobial defense, with chitinase significantly inhibiting yeast growth.
Conclusions:
- PR enzymes play a crucial role in protecting EFN from microbial infestation.
- The enhanced antimicrobial properties of myrmecophyte EFN are attributed to higher concentrations of specific PR enzymes.
- This study highlights a sophisticated indirect defense mechanism in plants utilizing EFN's antimicrobial components.
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