Dataset Information

Next generation mapping of the salicylic acid signaling hub and transcriptional cascade

ABSTRACT: For over 60 years, salicylic acid (SA) has been known as a plant immune signal required for both basal and systemic acquired resistance (SAR). SA activates these immune responses by reprogramming up to 20% of the transcriptome through the function of NPR1. However, components in the NPR1-signaling hub, which appears as nuclear condensates, and the cascade of the NPR1-signaling pathway remained elusive due to difficulties in studying transcriptional cofactors whose chromosomal associations are often indirect and transient. To overcome this challenge, we applied TurboID to divulge the NPR1-proxiome, which detected key known NPR1-interactors and many new components of transcription-related complexes.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Whole Body

SUBMITTER: Shouling Xu

LAB HEAD: SHOULING XU

PROVIDER: PXD047543 | Pride | 2025-05-06

REPOSITORIES: Pride

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Next-generation mapping of the salicylic acid signaling hub and transcriptional cascade.

Powers Jordan J Zhang Xing X Reyes Andres V AV Zavaliev Raul R Ochakovski Roni R Xu Shou-Ling SL Dong Xinnian X

Molecular plant 20240822 10

For over 60 years, salicylic acid (SA) has been known as a plant immune signal required for basal and systemic acquired resistance. SA activates these immune responses by reprogramming ∼20% of the transcriptome through NPR1. However, components in the NPR1 signaling hub, which appears as nuclear condensates, and the NPR1 signaling cascade have remained elusive due to difficulties in studying this transcriptional cofactor, whose chromatin association is indirect and likely transient. To overcome ...[more]

PMID: 39180213

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Project description:Identifying specific protein interactors and spatially or temporally restricted local proteomes contributes significantly to our understanding of cellular processes in virtually all aspects of life. Obtaining such data is challenging, especially when the protein, cell type or event of interest is rare. In recent years, different proximity labeling techniques have been developed that have greatly improved our ability to tackle these questions. However, while effective in mammalian systems, use in plants has been extremely limited due to technical challenges. Recent technological improvements in the form of two highly active versions of the biotin ligase BirA* (TurboID and miniTurboID), prompted us to test this new system on two challenging but widely asked questions in plants: what are interaction partners of low-abundant proteins and what are organellar proteomes in rare and transient cell types. To address the second question, we used nuclei of developing stomatal guard cells, which express the transcription factor FAMA, as our test case. FAMA is a master regulator of guard cell development and promotes terminal differentiation of the guard cell precursor by both activating and repressing hundreds of genes. FAMA-expressing young guard cells are rare and restricted to the epidermis of developing aerial tissues, which makes them a good model system to test TurboID applicability under material-limiting conditions. For this experiment, young Arabidopsis seedlings expressing nuclear TurboID under the FAMA or UBIQUITIN10 (UBQ10) promoter were treated with biotin to label nuclear proteomes. Col-0 wild type was used as controls for unspecific binding of proteins to the beads. Biotinylated proteins were isolated by affinity purification with streptavidin-coupled beads and identified by LC-MS/MS. By targeting TurboID to the nucleus we were able to purify nuclear proteins with relatively high specificity. Enrichment of FAMA-stage specific proteins, when nuclear TurboID was driven by the FAMA compared to the UBQ10 promoter, supports general applicability of TurboID for identification of subcellular proteomes.

Project description:Identifying specific protein interactors and spatially or temporally restricted local proteomes contributes significantly to our understanding of cellular processes in virtually all aspects of life. Obtaining such data is challenging, especially when the protein, cell type or event of interest is rare. In recent years, different proximity labeling techniques have been developed that have greatly improved our ability to tackle these questions. However, while effective in mammalian systems, use in plants has been extremely limited due to technical challenges. Recent technological improvements in the form of two highly active versions of the biotin ligase BirA* (TurboID and miniTurboID), prompted us to test this new system on two challenging but widely asked questions in plants: what are interaction partners of low-abundant proteins and what are organellar proteomes in rare and transient cell types. To address the first question, we used the transcription factor FAMA as a test case. FAMA is a master regulator of guard cell development and promotes terminal differentiation of the guard cell precursor by both activating and repressing hundreds of genes. FAMA-expressing young guard cells are rare and restricted to the epidermis of developing aerial tissues, which makes them a good model system to test TurboID applicability under material-limiting conditions. For this experiment, young Arabidopsis seedlings expressing FAMA-TurboID were treated with biotin to label FAMA complexes. Col-0 wild type and seedlings expressing nuclear TurboID under the FAMA promoter were used as controls for unspecific binding of proteins to the beads and stochastic labeling of nuclear proteins, respectively. Biotinylated proteins were isolated by affinity purification with streptavidin-coupled beads and identified by LC-MS/MS. Analysis of proteins labeled by FAMA-TurboID fusions revealed known interactors of this late stomatal lineage specific transcription factor, as well as novel proteins that could explain its dual function as an activator and repressor. Comparison with proteins obtained from classical co-immunoprecipitation approaches with FAMA showed that proximity labeling is superior for identification of meaningful interaction partners of low-abundant proteins.

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	Araport11_pep_20220914.fa	Other
	Q20220905_01.raw	Raw
	Q20220905_02.raw	Raw
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	Q20220905_05.raw	Raw