Identification and characterisation of NOT9B, a novel phytochrome a signalling component in arabidopsis thaliana

Abstract: Plants sense their environment using a sophisticated set of receptors to adjust their development to changing environmental cues. One of the factors that heavily shape plants’ life is light, as it is not only source of energy but also source of information. For the detection of light, plants have acquired a set of photorecptors in the course of evolution. In the red- and far-red spectrum of light, phytochromes are the crucial receptors. To relay the information gathered by these receptors to a change in growth they have evolved an intricate network of downstream factors, that reshape gene-expression in response to binding to phytochromes and ultimately influence plant development.
Using a Yeast-2-Hybrid screen, we identified NOT9B as a novel interaction partner of phytochrome A, the only far-red light receptor in Arabidopsis thaliana. NOT9B is part of the highly conserved CCR4-NOT complex, an integral and conserved part of the RNA metabolism in eukaryotes. We describe NOT9B as a negative regulator of far-red light signalling, and describe a mechanism by which photoactivated phytochrome A displaces NOT9B from NOT1, the CCR4-NOT scaffold protein.
ARGONAUTE 1 (AGO1) and proteins involved in splicing are shown to be in complex with NOT9B, and we show that knock-out plants of not9b display specific alterations in their splicing patterns in response to far-red light. We provide evidence, that NOT9B is in complex with nuclear AGO1 indicating a connection between phyA, NOT9B, and AGO1 in control of gene expression in response to light.
NOT9B is localized to both the nucleus and cytoplasmic phase separated foci called processing bodies (p-bodies). P-bodies store translationally halted mRNAs and release them in response to environmental stimuli, thereby exerting translational control circumventing de novo mRNA synthesis. We show that HA-YFP-NOT9B tagged processing bodies disassemble after red and far-red illumination and that this process is dependent on phyB and phyA respectively. Evidence is provided that cytoplasmic phyA is sufficient and required for the
p-body disassembly in response to far-red light, indicating a novel cytoplasmic phyA function.
In summary, NOT9B is a novel phyA interacting protein that modulates gene expression in response to far-red light and is a marker for p-bodies. These, in turn are disassembled via cytoplasmic phytochromes in response to light. Both aspects of NOT9B contribute to a deeper understanding of phytochrome signalling

Location
Deutsche Nationalbibliothek Frankfurt am Main
Extent
Online-Ressource
Language
Englisch
Notes
Universität Freiburg, Dissertation, 2021

Keyword
Pflanzen
Phytochrom
Ackerschmalwand
Mutante
Pflanzen
Lichtreiz

Event
Veröffentlichung
(where)
Freiburg
(who)
Universität
(when)
2021
Creator
Contributor

DOI
10.6094/UNIFR/222373
URN
urn:nbn:de:bsz:25-freidok-2223734
Rights
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Last update
25.03.2025, 1:47 PM CET

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Associated

Time of origin

  • 2021

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