Respiration in leaves and the continued elevation in the atmospheric
Plant steroid hormones brassinosteroids (
- NSF-PAR ID:
- 10371905
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 100
- Issue:
- 5
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 923-937
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Brassinosteroids (
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ABA ), but underlying mechanisms remain elusive. Here, we report that the sole Arabidopsis heterotrimeric Gβ subunit,AGB 1, is required for four guard cell Caoresponses: induction of stomatal closure; inhibition of stomatal opening; [Ca2+]cytoscillation; and inositol 1,4,5‐trisphosphate (InsP3) production. Stomata in wild‐type Arabidopsis (Col) and in mutants of the canonical Gα subunit,GPA 1agb1 mutants andagb1 /gpa1 double‐mutants, as well as those of theagg1agg2 Gγ double‐mutant, were insensitive to Cao. These behaviors contrast withABA ‐regulated stomatal movements, which involveGPA 1 andAGB 1/AGG 3 dimers, illustrating differential partitioning of G‐protein subunits among stimuli with similar ultimate impacts, which may facilitate stimulus‐specific encoding.AGB 1NO production, but lostYC 3.6‐detected [Ca2+]cytoscillations in response to Cao, initiating only a single [Ca2+]cytspike. Experimentally imposed [Ca2+]cytoscillations restored stomatal closure inagb1 . Yeast two‐hybrid and bimolecular complementation fluorescence experiments revealed thatAGB 1 interacts with phospholipase Cs (PLCs), and Caoinduced InsP3 production in Col but not inagb1 . In sum, G‐protein signaling viaAGB 1/AGG 1/AGG 2 is essential for Cao‐regulation of stomatal apertures, and stomatal movements in response to Caoapparently require Ca2+‐induced Ca2+release that is likely dependent on Gβγ interaction withPLC s leading to InsP3 production.
