CoSE logo Plant MitoCarta
Plant MitoCarta › NASA OSDR Studio › OSD-120
OSD-120 NASA Open Science Data Repository ISS APEX-03-2 (SpaceX CRS-5, Veggie Facility) Petri Plates in ISS Veggie / Light Growth Chamber 14 Days on Orbit in Microgravity Arabidopsis thaliana (Col-0 & WS)

ISS APEX-03-2: Spaceflight Impacts on Arabidopsis Root vs Shoot Bioenergetics

NASA OSDR Repository ↗ Project in Custom Omics Studio ↗
🔬

Biological Synopsis & Spaceflight Discoveries

APEX-03-2 profiled Arabidopsis tissue-specific transcriptomic adaptations to orbital microgravity aboard the International Space Station. Spaceflight triggers a pronounced bioenergetic crisis in roots, highlighted by severe upregulation of Alternative Oxidase 1a (AOX1a, +2.42 log2FC) and external NADH dehydrogenases (NDB2, +1.88 log2FC), along with activation of the ANAC017 mitochondrial retrograde signaling cascade. In contrast, shoots exhibit downregulation of photorespiratory glycine decarboxylase (GDCP, -1.45 log2FC) and photosynthetic reaction centers, demonstrating that roots and shoots adopt radically different organellar coping strategies under mechanical unloading.

Key Biological Insights:

Key Discovery: Severe induction of mitochondrial stress sentinel AOX1a in roots (+2.42 log2FC, p = 0.0001) as an essential non-phosphorylating electron overflow valve.
Key Discovery: Activation of the ANAC017-mediated Mitochondrial Retrograde Regulation (MRR) pathway in root tips under weightlessness.
Key Discovery: Complex I respiratory subunits (NDUFS4, NDUFV1) downregulated (-1.25 to -0.85 log2FC), signaling suppression of standard coupled OXPHOS.
Key Discovery: Selective downregulation of photorespiration enzymes (GDCP, SHMT1) in shoots reflecting altered gas exchange and convection in microgravity.

Primary Literature & Mission Reports:

🗺️

Pre-Projected Organellar Pathway Maps

High-resolution vector maps showing spaceflight log2 fold-changes dynamically color-coded with WCAG AAA luminance-adaptive text contrast.

Contrasts:
Plant Mitochondrial Electron Transport and Oxidative Phosphorylation Conserved respiratory Complexes I–V integrated with plant-specific bypasses (AOX, Type II NDHs, and the Complex I Carbonic Anhydrase domain). Mitochondrial Matrix IMM • LIPID BILAYER Mitochondrial Inner Membrane (IMM) CRISTAE IMM • INVAGINATION Mitochondrial Cristae PLANT HOLO-COMPLEX I (L-SHAPED SUPER-ASSEMBLY) 2e− bypass structural assembly 2e− QH2 QH2 QH2 QH2 relief valve 4e− -> 2 H2O Q cycle 1e− 1e− 4e− -> 2 H2O H+ gradient H+ gradient H+ gradient proton uncoupling electron leak electron leak stress signaling T4 Matrix NADH Pool matrix redox couple T4 Succinate Pool TCA cycle intermediate T4 Molecular Oxygen (O2) electron acceptor T1 8×Fe-S FMN Complex I (Catalytic Core) 14 conserved subunits T1 PLANT-SPECIFIC Complex I CA Domain CAL1/CAL2/CA1-3 • absent in mammals T1 FAD 3×Fe-S Complex II (SDH) SDH1-4 T1 PLANT BYPASS Internal Type II NDH NDA1/NDA2/NDC1 • matrix-facing T1 PLANT BYPASS External Type II NDH NDB1/NDB2/NDB4 • IMS-facing T4 Ubiquinone Pool (Q/QH2) membrane quinone T1 di-iron Fe-Fe CN-RESISTANT NO H+ PUMP Alternative Oxidase (AOX1a) T1 Rieske 2Fe-2S Cyt b Cyt c1 Complex III (bc1 Complex) Q cycle T4 Cytochrome c mobile IMS carrier T1 heme a3/CuB Complex IV (COX) terminal oxidase T1 ATP Synthase (F1Fo) H+ motor • yields ATP T1 Plant UCP1 (PUMP1) dissipates H+ • thermotolerance T1 Mitochondrial Superoxide/H2O2 retrograde signal • leak from CI/CIII T1 DTC Translocator exports citrate • epigenetic signaling
Hover over or click any pathway node in the map above to inspect locus ID, fold-change, significance, and biological role.
📊

Ranked Organellar Responders

All assayed mitochondrial, chloroplast, and peroxisomal loci in OSD-120, ranked by absolute fold-change.

Rank AGI Locus Symbol Subcompartment Log2 Fold-Change p-value Pathway / Biological Role Action