@article{5942793be5d44228bfe60886f099504b,
title = "Chloroplast quality control pathways are dependent on plastid DNA synthesis and nucleotides provided by cytidine triphosphate synthase two",
abstract = "Reactive oxygen species (ROS) produced in chloroplasts cause oxidative damage, but also signal to initiate chloroplast quality control pathways, cell death, and gene expression. The Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant produces the ROS singlet oxygen in chloroplasts that activates such signaling pathways, but the mechanisms are largely unknown. Here we characterize one fc2 suppressor mutation and map it to CYTIDINE TRIPHOSPHATE SYNTHASE TWO (CTPS2), which encodes one of five enzymes in Arabidopsis necessary for de novo cytoplasmic CTP (and dCTP) synthesis. The ctps2 mutation reduces chloroplast transcripts and DNA content without similarly affecting mitochondria. Chloroplast nucleic acid content and singlet oxygen signaling are restored by exogenous feeding of the dCTP precursor deoxycytidine, suggesting ctps2 blocks signaling by limiting nucleotides for chloroplast genome maintenance. An investigation of CTPS orthologs in Brassicaceae showed CTPS2 is a member of an ancient lineage distinct from CTPS3. Complementation studies confirmed this analysis; CTPS3 was unable to compensate for CTPS2 function in providing nucleotides for chloroplast DNA and signaling. Our studies link cytoplasmic nucleotide metabolism with chloroplast quality control pathways. Such a connection is achieved by a conserved clade of CTPS enzymes that provide nucleotides for chloroplast function, thereby allowing stress signaling to occur.",
keywords = "cellular degradation, chloroplast, nucleotide metabolism, organelle gene expression, photosynthesis, reactive oxygen species, signaling, singlet oxygen",
author = "Kamran Alamdari and Fisher, {Karen E.} and Tano, {David W.} and Snigdha Rai and Kyle Palos and Nelson, {Andrew D.L.} and Woodson, {Jesse D.}",
note = "Funding Information: We thank Dr Hans‐Henning Kunz (Washington State University) for generously sharing the vector constructs, Dr. Ramin Yadegari (University of Arizona) for providing a fluorescent microscope for phenotyping transgenic lines, Dr. David Baltrus (U. Arizona) for providing a plate reader for chlorophyll measurements, and Tania Chakraborty (University of Arizona) for proving technical assistance with RNA extraction, cDNA synthesis, and PCR. The authors acknowledge the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy grant DE‐SC0019573 and UA Core Facilities Pilot Program grant awarded to J.D.W, NSF‐IOS grant 1758532 awarded to A.D.L.N., and the NSF Graduate Research Fellowship Grant DGE‐1746060 awarded to K.R.P. The authors have no conflict of interest to declare. UBQ10::CTPS Funding Information: We thank Dr Hans-Henning Kunz (Washington State University) for generously sharing the UBQ10::CTPS vector constructs, Dr. Ramin Yadegari (University of Arizona) for providing a fluorescent microscope for phenotyping transgenic lines, Dr. David Baltrus (U. Arizona) for providing a plate reader for chlorophyll measurements, and Tania Chakraborty (University of Arizona) for proving technical assistance with RNA extraction, cDNA synthesis, and PCR. The authors acknowledge the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy grant DE-SC0019573 and UA Core?Facilities Pilot Program grant awarded to J.D.W, NSF-IOS grant 1758532 awarded to A.D.L.N., and the NSF Graduate Research Fellowship Grant DGE-1746060 awarded to K.R.P. The authors have no conflict of interest to declare. Publisher Copyright: {\textcopyright} 2021 The Authors New Phytologist {\textcopyright} 2021 New Phytologist Foundation.",
year = "2021",
month = aug,
doi = "10.1111/nph.17467",
language = "English (US)",
volume = "231",
pages = "1431--1448",
journal = "New Phytologist",
issn = "0028-646X",
publisher = "Wiley-Blackwell",
number = "4",
}