Cytokinin modulates the metabolic network of sulfur and glutathione

The phytohormone cytokinin is implicated in a range of growth, developmental, and defense processes. A growing body of evidence supports a crosstalk between cytokinin and nutrient signaling pathways, such as nitrate availability. Cytokinin signaling regulates sulfur-responsive gene expression, but t...

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Bibliographic Details
Published in:	Journal of experimental botany Vol. 73; no. 22; pp. 7417 - 7433
Main Authors:	Pavlů, Jaroslav, Kerchev, Pavel, Černý, Martin, Novák, Jan, Berka, Miroslav, Jobe, Timothy O, López Ramos, José Maria, Saiz-Fernández, Iñigo, Rashotte, Aaron Michael, Kopriva, Stanislav, Brzobohatý, Břetislav
Format:	Journal Article
Language:	English
Published:	England 08-12-2022
Subjects:	Arabidopsis thaliana cytokinin sulfur starvation glutathione xenobiotic tolerance nutrient homeostasis sulfur metabolism
Online Access:	Get full text
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Summary:	The phytohormone cytokinin is implicated in a range of growth, developmental, and defense processes. A growing body of evidence supports a crosstalk between cytokinin and nutrient signaling pathways, such as nitrate availability. Cytokinin signaling regulates sulfur-responsive gene expression, but the underlying molecular mechanisms and their impact on sulfur-containing metabolites have not been systematically explored. Using a combination of genetic and pharmacological tools, we investigated the interplay between cytokinin signaling and sulfur homeostasis. Exogenous cytokinin triggered sulfur starvation-like gene expression accompanied by a decrease in sulfate and glutathione content. This process was uncoupled from the activity of the major transcriptional regulator of sulfate starvation signaling SULFUR LIMITATION 1 and an important glutathione-degrading enzyme, γ-glutamyl cyclotransferase 2;1, expression of which was robustly up-regulated by cytokinin. Conversely, glutathione accumulation was observed in mutants lacking the cytokinin receptor ARABIDOPSIS HISTIDINE KINASE 3 and in cytokinin-deficient plants. Cytokinin-deficient plants displayed improved root growth upon exposure to glutathione-depleting chemicals which was attributed to a higher capacity to maintain glutathione levels. These results shed new light on the interplay between cytokinin signaling and sulfur homeostasis. They position cytokinin as an important modulator of sulfur uptake, assimilation, and remobilization in plant defense against xenobiotics and root growth.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0022-0957 1460-2431
DOI:	10.1093/jxb/erac391