Related Experiment Video
Updated: Aug 7, 2025
10:46
Evaluation of Photosynthetic Efficiency in Photorespiratory Mutants by Chlorophyll Fluorescence Analysis
Published on: December 9, 2022
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Transcriptome and Deletion Mutant Analyses Revealed that an RpoH Family Sigma Factor Is Essential for Photosystem
Tetsushi Suyama1, Nanako Kanno2, Satoko Matsukura1
1Bio-Analytical Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST).
Microbes and Environments
|March 6, 2023
Summary
Carbon starvation triggers photosynthesis gene expression in Roseateles depolymerans, regulated by the RpoH homologue SP70. This sigma factor is essential for pigment production and heat tolerance.
Area of Science:
- Microbiology
- Bacteriology
- Photosynthesis
Background:
- Roseateles depolymerans produces photosynthetic apparatus under carbon scarcity.
- Understanding gene regulation during carbon starvation is crucial.
Purpose of the Study:
- To investigate the transcriptomic changes in R. depolymerans under carbon starvation.
- To identify regulatory factors controlling photosynthesis gene expression.
Main Methods:
- Transcriptome analysis of R. depolymerans at 0, 1, and 6 hours post-carbon depletion.
- Gene knockout experiments of the SP70 sigma factor.
- Complementation studies by reintroducing the SP70 gene.
Main Results:
- Light-harvesting protein transcripts (PufA, PufB) showed a 500-fold increase.
- Photosynthetic gene clusters significantly upregulated under starvation.
- SP70 knockout mutants lacked photosynthetic pigments and showed reduced heat tolerance.
- SP70 is essential for the transcription of photosynthetic operons (puf, puh, bch).
Conclusions:
- The RpoH homologue SP70 is a key sigma factor regulating photosynthesis gene transcription in R. depolymerans.
- SP70 plays a dual role in photosynthesis and heat stress tolerance.
- SP70 is indispensable for the production of photosynthetic pigments.
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