Biology subjects

Dautermann, O.

Publications and source records attributed to Dautermann, O..

3 recordsLinked to original sources

bioRxiv2024

Both major xanthophyll cycles present in nature can provide Non-Photochemical Quenching in the model diatom Phaeodactylum tricornutum

Xanthophyll cycling contributes to photoprotection by regulating Non-Photochemical Quenching (NPQ). While most photosynthetic eukaryotes including land plants use the violaxanthin cycle, some algae like diatoms and haptophytes rely on the diadinoxanthin cycle for photoprotection. These algae also contain minor amounts of violaxanthin cycle pigments, serving as precursors in xanthophylls biosynthesis. Both cycles are catalyzed by the enzymes violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP). Here, we characterized the role of VDE and different ZEP-encoding paralogs (ZEP2 and ZEP3) in the model diatom Phaeodactylum tricornutum. While knockout of VDE and ZEP3 significantly impaired the diadinoxanthin cycle, lack of ZEP2 led to sustained accumulation of the violaxanthin cycle instead of diadinoxanthin cycle pigments under high irradiance, with no negative effect on NPQ capacity. We demonstrate that both major xanthophyll cycles present in nature can function with comparable efficiency within the same species, offering a new perspective on the evolution of xanthophyll-mediated photoprotection.

plant biology↗

bioRxiv2022

Metabolomic, photoprotective, and photosynthetic acclimatory responses to post-flowering drought in sorghum

Climate change is globally affecting rainfall patterns, necessitating the improvement of drought tolerance in crops. Sorghum bicolor is a drought-tolerant cereal capable of producing high yields under water scarcity conditions. Functional stay-green sorghum genotypes can maintain green leaf area and efficient grain filling in terminal post-flowering water deprivation, a period of ~10 weeks. To obtain molecular insights into these characteristics, two drought-tolerant genotypes, BTx642 and RTx430, were grown in control and terminal post-flowering drought field plots in the Central Valley of California. Photosynthetic, photoprotective, water dynamics, and biomass traits were quantified and correlated with metabolomic data collected from leaves, stems, and roots at multiple timepoints during drought. Physiological and metabolomic data was then compared to longitudinal RNA sequencing data collected from these two genotypes. The metabolic response to drought highlights the uniqueness of the post-flowering drought acclimation relative to pre-flowering drought. The functional stay-green genotype BTx642 specifically induced photoprotective responses in post-flowering drought supporting a putative role for photoprotection in the molecular basis of the functional stay-green trait. Specific genes are highlighted that may contribute to post-flowering drought tolerance and that can be targeted in crops to maximize yields under limited water input conditions. HighlightPathways contributing to the long-term maintenance of photosynthetic activity in terminal post-flowering drought are revealed by a comprehensive approach combining in-field photosynthetic physiological analysis, metabolomics, and transcriptomics.

plant biology↗

bioRxiv2021

High Light and High Temperature Reduce Photosynthesis via Different Mechanisms in the C4 Model Setaria viridis

C4 plants frequently experience damaging high light (HL) and high temperature (HT) conditions in native environments, which reduce growth and yield. However, the mechanisms underlying these stress responses in C4 plants have been under-explored, especially the coordination between mesophyll (M) and bundle sheath (BS) cells. We investigated how the C4 model plant Setaria viridis responded to a four-hour HL or HT treatment at the photosynthetic, transcriptomic, and ultrastructural levels. Although we observed a comparable reduction of photosynthetic efficiency in HL- or HT-treated leaves, detailed analysis of multi-level responses revealed important differences in key pathways and M/BS specificity responding to HL and HT. We provide a systematic analysis of HL and HT responses in S. viridis, reveal different acclimation strategies to these two stresses in C4 plants, discover unique light/temperature responses in C4 plants in comparison to C3 plants, and identify potential targets to improve abiotic stress tolerance in C4 crops.

plant biology↗