Journal
PLANT CELL AND ENVIRONMENT
Volume 41, Issue 8, Pages 1912-1925Publisher
WILEY
DOI: 10.1111/pce.13336
Keywords
ABA signalling; ABI5; BBX21; drought; hormones; HRB2; light quality; stomata
Categories
Funding
- Division of Molecular and Cellular Biosciences [MCB 1021645]
- National Natural Science Foundation of China [31470379]
- National Science Foundation [MCB 1021645, IIS 1149697]
Ask authors/readers for more resources
Blue light triggers the opening of stomata in the morning to allow CO2 uptake and water loss through transpiration. During the day, plants may experience periodic drought and accumulate abscisic acid (ABA). ABA antagonizes blue light signalling through phosphatidic acid and reduces stomatal aperture. This study reveals a molecular mechanism by which two light signalling proteins interact to repress ABA signalling in the control of stomatal aperture. A hypersensitive to red and blue 2 (hrb2) mutant has a defective ATP-dependent chromatin-remodelling factor, PKL, in the chromodomain/helicase/DNA binding family. HRB2 enhances the light-induced expression of a B-box transcription factor gene, BBX21. BBX21 binds a T/G box in the ABI5 promoter and recruits HRB2 to modulate the chromatin structure at the ABI5 locus. Mutation in either HRB2 or BBX21 led to reduced water loss and ABA hypersensitivity. This hypersensitivity to ABA was well explained by the enhanced expression of the ABA signalling gene ABI5 in both mutants. Indeed, stomatal aperture was significantly reduced by ABI5 overexpression in the absence or presence of ABA under monochromatic light conditions. Overall, we present a regulatory loop in which two light signalling proteins repress ABA signalling to sustain gas exchange when plants experience periodic drought.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available