TOR coordinates nucleotide availability with ribosome biogenesis in plants.

Autor:	Busche M; Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.; Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA 94710, USA., Scarpin MR; Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.; Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA 94710, USA., Hnasko R; Produce Safety and Microbiology Research Unit, Western Regional Research Center, Pacific West Area, USDA Agricultural Research Service, Albany, CA 94710,USA., Brunkard JO; Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.; Plant Gene Expression Center, USDA Agricultural Research Service, Albany, CA 94710, USA.
Jazyk:	angličtina
Zdroj:	The Plant cell [Plant Cell] 2021 Jul 02; Vol. 33 (5), pp. 1615-1632.
DOI:	10.1093/plcell/koab043
Abstrakt:	TARGET OF RAPAMYCIN (TOR) is a conserved eukaryotic Ser/Thr protein kinase that coordinates growth and metabolism with nutrient availability. We conducted a medium-throughput functional genetic screen to discover essential genes that promote TOR activity in plants, and identified a critical regulatory enzyme, cytosolic phosphoribosyl pyrophosphate (PRPP) synthetase (PRS4). PRS4 synthesizes cytosolic PRPP, a key upstream metabolite in nucleotide synthesis and salvage pathways. We found that prs4 knockouts are embryo-lethal in Arabidopsis thaliana, and that silencing PRS4 expression in Nicotiana benthamiana causes pleiotropic developmental phenotypes, including dwarfism, aberrant leaf shape, and delayed flowering. Transcriptomic analysis revealed that ribosome biogenesis is among the most strongly repressed processes in prs4 knockdowns. Building on these results, we discovered that TOR activity is inhibited by chemical or genetic disruption of nucleotide biosynthesis, but that this effect can be reversed by supplying plants with nucleobases. Finally, we show that TOR transcriptionally promotes nucleotide biosynthesis to support the demands of ribosomal RNA synthesis. We propose that TOR coordinates ribosome biogenesis with nucleotide availability in plants to maintain metabolic homeostasis and support growth. (© American Society of Plant Biologists 2021. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
Databáze:	MEDLINE
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