Sjon Hartman

@hartman-plantlab.com

2192 Followers 1177 Following

Plant Biologist 🌱 Junior Professor of Plant Environmental Signalling & Development 🧬🔬 Studying Flooding Tolerance & Epigenetic Memory 🌊 at @biologyunifreiburg.bsky.social @uni-freiburg.de @cibss.bsky.social www.hartman-plantlab.com

Lab group photo after the B2Run Freiburg charity running event.
Circular schematic illustrating signalling events before, during and after plant submergence. The figure is divided into three interconnected phases arranged around a central ring labeled “Acclimation,” “Submergence,” and “Recovery,” with ethylene (Et) positioned at the center as a key regulator. The upper left region “Acclimation” depicts environmental flooding anticipation cues, including rain, waterlogging, humidity, and mechano-stimulation, leading to activation of EIN3 signalling. The upper right half, labeled as “Hypoxia,” represents submerged conditions with blue shading. Ethylene signalling through EIN2 stabilizes EIN3 and promotes accumulation of PGB1, which limits nitric oxide (NO)-dependent degradation of ERFVII transcription factors. Translation is globally repressed while stress-induced mRNA translation is promoted through GCN2. Sugar-dependent TOR signalling phosphorylates ERFVII, enabling interaction with MED25 and RNA polymerase II to activate hypoxia-responsive genes (HRGs). EIN3 also promotes ORE1-mediated senescence in old leaves, while miR164 suppresses ORE1 activity in young leaves. The lower left recovery section, shaded yellow, depicts re-oxygenation after flooding. Oxygen and hydrogen peroxide generated during a reactive oxygen species (ROS) burst stabilize ERFVII and activate oxidative stress-responsive genes (ORGs) while repressing HRGs. Ethylene signalling is attenuated through EBF-mediated ubiquitin–proteasome system (UPS) degradation and autophagic turnover of EIN3. Curved arrows around the outer circle indicate progression through flooding, hypoxia, and recovery, emphasizing that these signalling events are overlapping and interconnected rather than strictly linear.
Photo showing Sjon receiving his laudatio from his supervisor Rens Voesenek in the Academiegebouw of Utrecht University.