1. The Stomatal Response to Reduced Relative Humidity Requires Guard Cell-Autonomous ABA Synthesis
- Author
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Nicole Lachmann, Sophia Sonnewald, Joerg Fromm, Ralf R. Mendel, Susanne Kneitz, Florian Bittner, Alistair M. Hetherington, Uwe Sonnewald, Wolfram Hartung, Khaled A. S. Al-Rasheid, Hubert Bauer, Peter Ache, Rainer Hedrich, and Silke Lautner
- Subjects
Mutant ,Arabidopsis ,Photosynthesis ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,Guard cell ,Botany ,Arabidopsis thaliana ,Abscisic acid ,Feedback, Physiological ,biology ,Agricultural and Biological Sciences(all) ,Biochemistry, Genetics and Molecular Biology(all) ,Molybdenum cofactor sulfurase ,fungi ,Plant Stomata ,food and beverages ,Humidity ,Carbon Dioxide ,biology.organism_classification ,chemistry ,Biophysics ,Transcriptome ,General Agricultural and Biological Sciences ,Abscisic Acid - Abstract
SummaryStomata are pores on the leaf surface, bounded by two guard cells, which control the uptake of CO2 for photosynthesis and the concomitant loss of water vapor. In 1898, Francis Darwin [1] showed that stomata close in response to reduced atmospheric relative humidity (rh); however, our understanding of the signaling pathway responsible for coupling changes in rh to alterations in stomatal aperture is fragmentary. The results presented here highlight the primacy of abscisic acid (ABA) in the stomatal response to drying air. We show that guard cells possess the entire ABA biosynthesis pathway and that it appears upregulated by positive feedback by ABA. When wild-type Arabidopsis and the ABA-deficient mutant aba3-1 were exposed to reductions in rh, the aba3-1 mutant wilted, whereas the wild-type did not. However, when aba3-1 plants, in which ABA synthesis had been specifically rescued in guard cells, were challenged with dry air, they did not wilt. These data indicate that guard cell-autonomous ABA synthesis is required for and is sufficient for stomatal closure in response to low rh. Guard cell-autonomous ABA synthesis allows the plant to tailor leaf gas exchange exquisitely to suit the prevailing environmental conditions.
- Published
- 2013
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