Transcriptional Regulation of the Glucose-6-Phosphate/Phosphate Translocator 2 Is Related to Carbon Exchange Across the Chloroplast Envelope

Journal Article · 27 June 2019 · Frontiers in Plant Science

DOI: https://doi.org/10.3389/fpls.2019.00827 · OSTI ID:1607925

Weise, Sean E. ^[1]; Liu, Tiffany ^[2]; Childs, Kevin L. ^[2]; Preiser, Alyssa L. ^[3]; Katulski, Hailey M. ^[3]; Perrin-Porzondek, Christopher ^[3]; Sharkey, Thomas D. ^[4]

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1. Michigan State Univ., East Lansing, MI (United States). MSU-DOE Plant Research Laboratory and Dept. of Biochemistry and Molecular Biology
2. Michigan State Univ., East Lansing, MI (United States). Dept. of Plant Biology
3. Michigan State Univ., East Lansing, MI (United States). MSU-DOE Plant Research Laboratory
4. Michigan State Univ., East Lansing, MI (United States). MSU-DOE Plant Research Laboratory, Dept. of Biochemistry and Molecular Biology, and Plant Resilience Institute

The exchange of reduced carbon across the inner chloroplast envelope has a large impact on photosynthesis and growth. Under steady-state conditions it is thought that glucose 6-phosphate (G6P) does not cross the chloroplast membrane. However, growth at high CO₂, or disruption of starch metabolism can result in the GPT2 gene for a G6P/P_i translocator to be expressed presumably allowing G6P exchange across the chloroplast envelope. We found that after an increase in light, the transcript for GPT2 transiently increases several 100-fold within 2 h in both the Col-0 and WS ecotypes of Arabidopsis thaliana. The increase in transcript for GPT2 is preceded by an increase in transcript for many transcription factors including Redox Responsive Transcription Factor 1 (RRTF1). The increase in GPT2 transcript after exposure to high light is suppressed in a mutant lacking the RRTF1 transcription factor. The GPT2 response was also suppressed in a mutant with a T-DNA insert in the gene for the triose-phosphate/P_i translocator (TPT). However, plants lacking TPT still had a robust rise in RRTF1 transcript in response to high light. From this, we conclude that both RRTF1 (and possibly other transcription factors) and high amounts of cytosolic triose phosphate are required for induction of the expression of GPT2. We hypothesize that transient GPT2 expression and subsequent translation is adaptive, allowing G6P to move into the chloroplast

• Research Organization: Michigan State Univ., East Lansing, MI (United States). MSU-DOE Plant Research Laboratory
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: FG02-91ER20021
• OSTI ID: 1607925
• Journal Information: Frontiers in Plant Science, Vol. 10; ISSN 1664-462X
• Publisher: Frontiers Research FoundationCopyright Statement
• Country of Publication: United States
• Language: English