The Arabidopsis her1 mutant implicates GABA in E-2-hexenal responsiveness
Rossana Mirabella1, Han Rauwerda, Eduard A Struys
1Department of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.
The Plant Journal : for Cell and Molecular Biology
|November 1, 2007
Summary
Plants use C6-volatiles as signals for defense. Researchers found that high levels of gamma-aminobutyric acid (GABA) in Arabidopsis thaliana mediate responses to the specific volatile E-2-hexenal.
Area of Science:
- Plant Biology
- Plant Signaling
- Biochemistry
Background:
- Plants release C6-volatiles when damaged, which signal defense responses in neighbors.
- The molecular mechanisms of plant perception and response to C6-volatiles are not well understood.
- E-2-hexenal, a C6-volatile, specifically inhibits root elongation in Arabidopsis thaliana, independent of major plant hormones.
Purpose of the Study:
- To identify molecular mechanisms underlying plant responses to C6-volatiles.
- To characterize mutants in Arabidopsis thaliana with altered responses to E-2-hexenal.
- To elucidate the role of gamma-aminobutyric acid (GABA) in plant volatile signaling.
Main Methods:
- Isolation and genetic screening of E-2-hexenal-response (her) mutants in Arabidopsis thaliana.
- Map-based cloning and microarray analysis to identify the mutated gene in her1.
- Measurement of GABA levels in wild-type and mutant plants under E-2-hexenal treatment.
Main Results:
- 18 her mutants were isolated, exhibiting sustained root growth upon E-2-hexenal exposure.
- The her1 mutant accumulates high levels of GABA due to a mutation in the gamma-amino butyric acid transaminase (GABA-TP) gene.
- E-2-hexenal treatment induces GABA accumulation in wild-type plants, and high GABA levels confer resistance to E-2-hexenal.
Conclusions:
- Gamma-aminobutyric acid (GABA) plays a crucial role in mediating plant responses to the volatile E-2-hexenal.
- The GABA metabolic pathway is involved in plant perception and signaling of specific C6-volatiles.
- This study reveals a novel signaling pathway for plant defense volatiles.
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