TMK1-based auxin signaling regulates abscisic acid responses via phosphorylating ABI1/2 in Arabidopsis.
Proc Natl Acad Sci U S A
; 118(24)2021 06 15.
Article
in En
| MEDLINE
| ID: mdl-34099554
ABSTRACT
Differential concentrations of phytohormone trigger distinct outputs, which provides a mechanism for the plasticity of plant development and an adaptation strategy among plants to changing environments. However, the underlying mechanisms of the differential responses remain unclear. Here we report that a high concentration of auxin, distinct from the effect of low auxin concentration, enhances abscisic acid (ABA) responses in Arabidopsis thaliana, which partially relies on TRANS-MEMBERANE KINASE 1 (TMK1), a key regulator in auxin signaling. We show that high auxin and TMK1 play essential and positive roles in ABA signaling through regulating ABA INSENSITIVE 1 and 2 (ABI1/2), two negative regulators of the ABA pathway. TMK1 inhibits the phosphatase activity of ABI2 by direct phosphorylation of threonine 321 (T321), a conserved phosphorylation site in ABI2 proteins, whose phosphorylation status is important for both auxin and ABA responses. This TMK1-dependent auxin signaling in the regulation of ABA responses provides a possible mechanism underlying the high auxin responses in plants and an alternative mechanism involved in the coordination between auxin and ABA signaling.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Signal Transduction
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Protein Serine-Threonine Kinases
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Arabidopsis
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Abscisic Acid
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Phosphoprotein Phosphatases
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Arabidopsis Proteins
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Indoleacetic Acids
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
2021
Document type:
Article