Bernhard Wurzinger

Accurate pre-harvest prediction of crop yield informs variety selection, optimizes management, and accelerates breeding. As potato is the world’s leading non-grain staple, here we evaluate a diverse panel of varieties in a three-year field trial across five European locations. Canopy development and environmental parameters are monitored throughout the growing season using drone-based imaging, in-field sensors and gene expression measurements, while tuber yield and quality traits are quantified at harvest. We show that these data enable the identification of climate-resilient, high-yielding genotypes and support the development of machine learning models that explain over 80% of yield variation in independent test sets. Strikingly, measurements collected within the first two months after planting achieve predictive performance comparable to models trained on full-season data. Model interrogation further shows that over 70% of yield variation can already be predicted based on a simple five-parameter linear equation. Our framework thus demonstrates the potential of integrative field phenotyping and data-driven modeling to improve variety selection across heterogeneous environments.

SUMMARY: GERMIN3 has previously been identified as a target of the tuberigen activation complex, suggesting a function in potato tuberisation, but its role is presently unknown. In the present study, we analysed morphological, agronomic and molecular phenotypes of GERMIN3 transgenic lines in Solanum tuberosum ssp. andigena and in the tuberosum cultivar Desiree. GERMIN3 over‐expressing lines of S. tuberosum ssp. andigena exhibited increased tuber yields and enhanced tuber numbers. Post‐harvest tuber sprouting exhibited greater bud activation with increased numbers of sprouts. Axillary buds were also activated in aerial tissues of mature plants, resulting in increased stem branching. Similar results were observed in the commercial cultivar Desiree. Over‐expression of GERMIN3 had no impact on the expression of SP6A , a positive regulator of tuberisation, or TFL1B , a negative regulator. The GERMIN3 protein localised to the endoplasmic reticulum, and transient expression in N. benthamiana leaves resulted in plasmodesmatal gating, allowing intercellular transport of GFP‐tagged sporamin independent of GERMIN3 oxalate oxidase activity. We propose that GERMIN3 affects tuberisation and other developmental processes by facilitating meristem activation. This identifies GERMIN3 as a novel protein associated with control of plasmodesmatal transport and supports the importance of plasmodesmatal gating in the regulation of key potato developmental processes.

Calcium (Ca ²⁺ ) and reactive oxygen species (ROS) are key secondary messengers in plant stress signaling, yet their interplay in regulating proteome-wide responses remains poorly understood. In this study, we employed label-free quantitative (LFQ) proteomics to investigate Ca ²⁺ -dependent and independent changes in the proteome of Arabidopsis thaliana leaves upon oxidative stress induced by hydrogen peroxide (H ₂ O ₂ ). To dissect the role of Ca ²⁺ signaling, we inhibited H ₂ O ₂ -induced Ca ²⁺ transients by pretreatment with LaCl ₃ , a plasma membrane Ca ²⁺ channel blocker. We then analysed the proteome of plants treated with H ₂ 0 ₂ or ddH ₂ O after 10 and 30 min of treatment and detected 3724 and 3757 proteins, respectively. From these, 581 proteins showed significant changes in abundance after 10 min and 909 proteins after 30 min. Remarkably, the combined LaCl ₃ and H ₂ O ₂ treatment resulted in the highest number of differentially abundant proteins (DAPs), indicating a strong attenuating effect of Ca ²⁺ signaling on the oxidative stress response. Specifically responsive to only H ₂ O ₂ were 37 and 57 proteins with distinct subsets of strictly Ca ²⁺ -dependent, partially Ca ²⁺ - dependent, and Ca ²⁺ -independent proteins. Notably, Ca ²⁺ -independent H ₂ O ₂ -responsive proteins predominantly showed increased abundance, while strictly Ca ²⁺ -dependent proteins exhibited decreased abundance, suggesting a role for Ca ²⁺ signaling in protein degradation. Furthermore, three proteins—WLIM1, CYP97C1, and AGAP1—underwent Ca ²⁺ -dependent shifts between the two time points, pointing to a dynamic nature of Ca ²⁺ -regulated proteomic changes. This study provides novel insights into short-term Ca ²⁺ -dependent and independent regulation of the Arabidopsis leaf proteome in response to oxidative stress, identifying key stress-responsive proteins and potential new targets for further research on plant stress resilience mechanisms.

Potato (Solanum tuberosum) is highly water and space efficient but susceptible to abiotic stresses such as heat, drought, and flooding, which are severely exacerbated by climate change. Our understanding of crop acclimation to abiotic stress, however, remains limited. Here, we present a comprehensive molecular and physiological high-throughput profiling of potato (Solanum tuberosum, cv. Désirée) under heat, drought, and waterlogging applied as single stresses or in combinations designed to mimic realistic future scenarios. Stress responses were monitored via daily phenotyping and multi-omics analyses of leaf samples comprising proteomics, targeted transcriptomics, metabolomics, and hormonomics at several timepoints during and after stress treatments. Additionally, critical metabolites of tuber samples were analyzed at the end of the stress period. We performed integrative multi-omics data analysis using a bioinformatic pipeline that we established based on machine learning and knowledge networks. Waterlogging produced the most immediate and dramatic effects on potato plants, interestingly activating ABA responses similar to drought stress. In addition, we observed distinct stress signatures at multiple molecular levels in response to heat or drought and to a combination of both. In response to all treatments, we found a downregulation of photosynthesis at different molecular levels, an accumulation of minor amino acids, and diverse stress-induced hormones. Our integrative multi-omics analysis provides global insights into plant stress responses, facilitating improved breeding strategies toward climate-adapted potato varieties.

Summary: GERMIN3 has previously been identified as a target of the tuberigen activation complex suggesting a function in potato tuberisation but its role is presently unknown. To understand the role of GERMIN3 we analysed morphological, agronomic and molecular phenotypes in transgenic lines. GERMIN3 over-expressing lines of Solanum tuberosum ssp. andigena exhibited increased tuber yields under permissive conditions and enhanced tuber numbers. Post-harvest tuber sprouting exhibited reduced apical dominance with increased numbers of sprouts. Apical dominance was reduced in aerial tissues of mature plants where stem growth from axillary buds was activated. Similar results were observed in the commercial cultivar Desiree. Over-expression of GERMIN3 had no impact on the expression of SP6A , a positive regulator of tuberisation or TFL1B , a negative regulator. The GERMIN3 protein localised to the endoplasmic reticulum and transient expression in N. benthamiana leaves resulted in plasmodesmatal gating allowing intercellular transport of GFP-tagged sporamin independent of GERMIN3 oxalate oxidase activity. GERMIN3 affects tuberisation and other developmental processes by facilitating meristem activation. This identifies GERMIN3 as a novel protein associated with control of plasmodesmatal transport and supports the importance of plasmodesmatal gating in the regulation of key potato developmental processes.

Chloroplast development is initiated by light-signals triggering the expression of nuclear encoded chloroplast genes in a first phase, followed by massive structural changes in the transition from proplastids to mature chloroplasts in the second phase. While the molecular players involved in the first phase are currently emerging, regulatory components of the second phase, demanding high plastid translational capacity and RNA processing, are still enigmatic. This is mostly due to the very limited amount of plant material at the early phases of development that makes biochemical studies such as identifying protein interaction networks very difficult. To overcome this problem, we developed a TurboID-based proximity labelling workflow that requires only very limited sample amounts to obtain mechanistic insights into protein interaction networks present in the early stages of plastid development. We used the CGL20a protein, a novel factor involved in chloroplast development, as bait for in vivo proximity labelling in developing seedlings 7 days after germination. We found that CGL20a resides in a nexus of RNA binding proteins mainly associated to ribosomal RNA (rRNA) including different ribosome-associated proteins. One-sentence summary: The use of plastid-specific in vivo proximity labelling in Arabidopsis seedlings allows to identify novel components in chloroplast development in higher plants.

Phytohormones are major signaling components that contribute to nearly all aspects of plant life. They constitute an interconnected communication network to finetune growth and development in response to the ever-changing environment. To this end, they have to coordinate with other signaling components, such as reactive oxygen species (ROS) and calcium signals. Especially the two endosymbiotic organelles, plastids and mitochondria, control various aspects of phytohormone signaling and harbour important steps of hormone precursor biosynthesis. Vice versa, phytohormones have feedback actions on organellar functions. Besides that, organelles and phytohormones often act in parallel in a coordinated matter to regulate cellular functions. Therefore, linking organelle functions with the increasing knowledge about phytohormone biosynthesis, perception and signaling will reveal new aspects of plant stress tolerance. In this review, we high-light recent work on organelle-phytohormone interactions focusing on the major stress related hormones abscisic acid (ABA), jasmonates, salicylic acid (SA) and ethylene.

SnRK1 is a central integrator of energy signaling in different subcellular locations with emerging roles in organellar and hormone metabolism.

The evolutionarily highly conserved SNF1‐related protein kinase (SnRK1) protein kinase is a metabolic master regulator in plants, balancing the critical energy consumption between growth‐ and stress response‐related metabolic pathways. While the regulation of the mammalian [AMP‐activated protein kinase (AMPK)] and yeast (SNF1) orthologues of SnRK1 is well‐characterised, the regulation of SnRK1 kinase activity in plants is still an open question. Here we report that the activity and T‐loop phosphorylation of AKIN10, the kinase subunit of the SnRK1 complex, is regulated by the redox status. Although this regulation is dependent on a conserved cysteine residue, the underlying mechanism is different to the redox regulation of animal AMPK and has functional implications for the regulation of the kinase complex in plants under stress conditions.

Since years, research on SnRK1, the major cellular energy sensor in plants, has tried to define its role in energy signalling. However, these attempts were notoriously hampered by the lethality of a complete knockout of SnRK1. Therefore, we generated an inducible amiRNA::SnRK1α2 in a snrk1α1 knock out background (snrk1α1/α2) to abolish SnRK1 activity to understand major systemic functions of SnRK1 signalling under energy deprivation triggered by extended night treatment. We analysed the in vivo phosphoproteome, proteome and metabolome and found that activation of SnRK1 is essential for repression of high energy demanding cell processes such as protein synthesis. The most abundant effect was the constitutively high phosphorylation of ribosomal protein S6 (RPS6) in the snrk1α1/α2 mutant. RPS6 is a major target of TOR signalling and its phosphorylation correlates with translation. Further evidence for an antagonistic SnRK1 and TOR crosstalk comparable to the animal system was demonstrated by the in vivo interaction of SnRK1α1 and RAPTOR1B in the cytosol and by phosphorylation of RAPTOR1B by SnRK1α1 in kinase assays. Moreover, changed levels of phosphorylation states of several chloroplastic proteins in the snrk1α1/α2 mutant indicated an unexpected link to regulation of photosynthesis, the main energy source in plants.