Chlamydomonas mutants lacking chloroplast TRIOSE PHOSPHATE TRANSPORTER3 are metabolically compromised and light sensitive.

Autor:	Huang W; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA., Krishnan A; Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA., Plett A; Institute of Plant Biochemistry, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany., Meagher M; Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA., Linka N; Institute of Plant Biochemistry, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany., Wang Y; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.; School of Life Sciences, Tsinghua University, 100084 Beijing, China., Ren B; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA., Findinier J; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA., Redekop P; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA., Fakhimi N; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA., Kim RG; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA., Karns DA; Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA., Boyle N; Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA., Posewitz MC; Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA., Grossman AR; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.
Jazyk:	angličtina
Zdroj:	The Plant cell [Plant Cell] 2023 Jun 26; Vol. 35 (7), pp. 2592-2614.
DOI:	10.1093/plcell/koad095
Abstrakt:	Modulation of photoassimilate export from the chloroplast is essential for controlling the distribution of fixed carbon in the cell and maintaining optimum photosynthetic rates. In this study, we identified chloroplast TRIOSE PHOSPHATE/PHOSPHATE TRANSLOCATOR 2 (CreTPT2) and CreTPT3 in the green alga Chlamydomonas (Chlamydomonas reinhardtii), which exhibit similar substrate specificities but whose encoding genes are differentially expressed over the diurnal cycle. We focused mostly on CreTPT3 because of its high level of expression and the severe phenotype exhibited by tpt3 relative to tpt2 mutants. Null mutants for CreTPT3 had a pleiotropic phenotype that affected growth, photosynthetic activities, metabolite profiles, carbon partitioning, and organelle-specific accumulation of H2O2. These analyses demonstrated that CreTPT3 is a dominant conduit on the chloroplast envelope for the transport of photoassimilates. In addition, CreTPT3 can serve as a safety valve that moves excess reductant out of the chloroplast and appears to be essential for preventing cells from experiencing oxidative stress and accumulating reactive oxygen species, even under low/moderate light intensities. Finally, our studies indicate subfunctionalization of the TRIOSE PHOSPHATE/PHOSPHATE TRANSLOCATOR (CreTPT) transporters and suggest that there are differences in managing the export of photoassimilates from the chloroplasts of Chlamydomonas and vascular plants. Competing Interests: Conflict of interest statement. The authors declare no conflict of interest regarding this study. (© American Society of Plant Biologists 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
Databáze:	MEDLINE
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