Multiomics dissection of the CO2-dependent fast growth of Picochlorum celeri
- 1Colorado School of Mines
Abstract
With a sub-3-micrometer cell and a 27-Mbp diploid genome, the small but mighty Picochlorum celeri doubles within three hours and exceeds 30 g m-2 d-1 outdoors with CO2 supplied. In climate-simulating photobioreactors, productivity declined from 39 g m-2 d-1 under 2.25% CO2 to near zero in air and resumed within hours of CO2 restoration with photosystem II photochemistry largely retained. We profiled the transcriptome, proteome, phosphoproteome, ubiquitinome, acetylome, metabolome and lipidome, including the first site-resolved green-algal ubiquitinome. In air, the Rubisco large subunit tripled to 7.6% of protein while its two small-subunit isoforms, 70% identical, exchanged near-reciprocally, a novel CO2-dependent switch that we propose retunes Rubisco to low CO2. Photorespiratory enzymes increased in abundance whereas proteins involved in external nitrogen assimilation decreased, consistent with increased reliance on internal nitrogen recycling as carbon fixation became limiting. Transcript and protein responses were nearly uncoupled, with cytosolic ribosomal proteins declining despite increased transcripts and plastid ribosomal proteins spared. Phosphorylation was extensively remodeled, as were the lysine modifications ubiquitination, acetylation and CO2-dependent carbamylation, where a CO2-competition assay identified 86 bicarbonate-protected lysines, including RbcL K252. CO2 limitation therefore imposes a reversible growth arrest that reduces cytosolic translational investment while preserving photosynthetic capacity for rapid recovery.
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BibTeX
@misc{torrestiji2026multiomics,
title = {{Multiomics dissection of the CO2-dependent fast growth of Picochlorum celeri}},
author = {Y. Torres-Tiji and T. Ekness and D. Karns and C. Posso and L. M. Markillie and K. Bloodsworth and N. Munoz Munoz and M. Gritsenko and D. MacLaughlin and K. Carpenter and M. K. Hampton and N. Furrer and A. LaPanse and H. Mitchell and V. A. Petyuk and N. B. Chowdhury and A. Jerger and D. N. Kim and J. M. Fulcher and R. Chu and R. Moore and V. L. Paurus and P. Lalli and J. Eder and E. S. Nakayasu and P. Piehowski and A. Cintolesi and J. Zucker and A. Beliaev and M. Posewitz},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.27.753040},
url = {https://www.biorxiv.org/content/10.64898/2026.09.27.753040v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Multiomics dissection of the CO2-dependent fast growth of Picochlorum celeri
AU - Y. Torres-Tiji
AU - T. Ekness
AU - D. Karns
AU - C. Posso
AU - L. M. Markillie
AU - K. Bloodsworth
AU - N. Munoz Munoz
AU - M. Gritsenko
AU - D. MacLaughlin
AU - K. Carpenter
AU - M. K. Hampton
AU - N. Furrer
AU - A. LaPanse
AU - H. Mitchell
AU - V. A. Petyuk
AU - N. B. Chowdhury
AU - A. Jerger
AU - D. N. Kim
AU - J. M. Fulcher
AU - R. Chu
AU - R. Moore
AU - V. L. Paurus
AU - P. Lalli
AU - J. Eder
AU - E. S. Nakayasu
AU - P. Piehowski
AU - A. Cintolesi
AU - J. Zucker
AU - A. Beliaev
AU - M. Posewitz
PY - 2026
DA - 2026/09/27
PB - bioRxiv
DO - 10.64898/2026.09.27.753040
UR - https://www.biorxiv.org/content/10.64898/2026.09.27.753040v1
AB - With a sub-3-micrometer cell and a 27-Mbp diploid genome, the small but mighty Picochlorum celeri doubles within three hours and exceeds 30 g m-2 d-1 outdoors with CO2 supplied. In climate-simulating photobioreactors, productivity declined from 39 g m-2 d-1 under 2.25% CO2 to near zero in air and resumed within hours of CO2 restoration with photosystem II photochemistry largely retained. We profiled the transcriptome, proteome, phosphoproteome, ubiquitinome, acetylome, metabolome and lipidome, including the first site-resolved green-algal ubiquitinome. In air, the Rubisco large subunit tripled to 7.6% of protein while its two small-subunit isoforms, 70% identical, exchanged near-reciprocally, a novel CO2-dependent switch that we propose retunes Rubisco to low CO2. Photorespiratory enzymes increased in abundance whereas proteins involved in external nitrogen assimilation decreased, consistent with increased reliance on internal nitrogen recycling as carbon fixation became limiting. Transcript and protein responses were nearly uncoupled, with cytosolic ribosomal proteins declining despite increased transcripts and plastid ribosomal proteins spared. Phosphorylation was extensively remodeled, as were the lysine modifications ubiquitination, acetylation and CO2-dependent carbamylation, where a CO2-competition assay identified 86 bicarbonate-protected lysines, including RbcL K252. CO2 limitation therefore imposes a reversible growth arrest that reduces cytosolic translational investment while preserving photosynthetic capacity for rapid recovery.
ER -