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  • TOR senses and regulates spermidine metabolism during seedling establishment and growth in maize and Arabidopsis.

TOR senses and regulates spermidine metabolism during seedling establishment and growth in maize and Arabidopsis.

iScience (2021-11-13)
Kenia Salazar-Díaz, Yihan Dong, Csaba Papdi, Ernesto Miguel Ferruzca-Rubio, Grecia Olea-Badillo, Lyubov A Ryabova, Tzvetanka D Dinkova
ABSTRACT

Spermidine (Spd) is a nitrogen sink and signaling molecule that plays pivotal roles in eukaryotic cell growth and must be finetuned to meet various energy demands. In eukaryotes, target of rapamycin (TOR) is a central nutrient sensor, especially N, and a master-regulator of growth and development. Here, we discovered that Spd stimulates the growth of maize and Arabidopsis seedlings through TOR signaling. Inhibition of Spd biosynthesis led to TOR inactivation and growth defects. Furthermore, disruption of a TOR complex partner RAPTOR1B abolished seedling growth stimulation by Spd. Strikingly, TOR activated by Spd promotes translation of key metabolic enzyme upstream open reading frame (uORF)-containing mRNAs, PAO and CuAO, by facilitating translation reinitiation and providing feedback to polyamine metabolism and TOR activation. The Spd-TOR relay protected young-age seedlings of maize from expeditious stress heat shock. Our results demonstrate Spd is an upstream effector of TOR kinase in planta and provide its potential application for crop protection.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Cyclohexylamine, ReagentPlus®, ≥99.9%
Sigma-Aldrich
1-Naphthaleneacetic acid, suitable for plant cell culture, BioReagent, ≥95%, crystalline
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4-Methylumbelliferyl-β-D-glucuronide hydrate, ≥98% (HPLC), BioReagent, for identification of transformed plants
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Cycloheximide, ≥90% (HPLC)
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Proteinase K from Tritirachium album, lyophilized powder, BioUltra, ≥30 units/mg protein, for molecular biology
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MES, low moisture content, ≥99% (titration)
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Murashige and Skoog Basal Medium, powder, suitable for plant cell culture
Sigma-Aldrich
Heparin sodium salt from porcine intestinal mucosa, Grade I-A, ≥180 USP units/mg, powder, BioReagent, suitable for cell culture
Sigma-Aldrich
Spermidine, ≥99% (GC)
Roche
cOmplete, EDTA-free Protease Inhibitor Cocktail, Tablets provided in EASYpacks