We have launched a new Review Highlights series to showcase some of the most impactful review articles published with us. Each spotlight will provide a quick overview of the topic, key insights, and why it matters in a broader sense. 
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Superfood or sensory struggle?
-Understanding consumer hesitation toward microalgae
Microalgae contain high-quality proteins with balanced essential amino acids, polyunsaturated fatty acids, vitamins, pigments, and bioactive compounds. Their nutritional density has led to their classification as promising alternative food ingredients. Olsen et al. (2024) emphasize that species such as Arthrospira and Chlorella demonstrate particularly strong nutrient profiles, supporting their potential role in future sustainable diets.
Why consumers remain hesitant
Despite strong nutritional attributes, consumer acceptance remains limited. Surveys across Europe indicate that while microalgae are generally accepted as ingredients when incorporated at low levels, they are not yet widely adopted as primary food sources. Key barriers include unfamiliarity, strong sensory impressions, and concerns about how algae-based foods compare to conventional products. The review notes that familiarity increases acceptance, but only when sensory characteristics remain subtle.
What sensory science reveals
Sensory drivers, flavor, aroma, color, and texture, are central to consumer rejection. Olsen et al. describe how off-flavors arise from volatile compounds linked to lipid oxidation, pigments, and species-specific metabolites. Marine microalgae often exhibit fishy aromas due to PUFA oxidation, while green species may produce grassy or earthy notes. Color is equally influential: strong green or dark tones reduce acceptability unless masked within the food matrix. Texture changes, such as increased graininess or viscosity, further limit the inclusion of higher levels.
How processing can improve acceptance
Processing plays a critical role in modifying sensory attributes. The review highlights techniques such as cell disruption, extraction, deodorization, and the selective removal of pigments or lipids, all of which are capable of reducing undesirable flavors and colors. However, processing must be balanced against preserving nutritional value and maintaining cost-efficiency. Olsen et al. emphasize that optimized processing strategies, targeting the reduction of volatile off-flavor compounds, are necessary to enable higher incorporation rates in consumer products.
What messaging works best
Communication strategies materially influence consumer willingness to try microalgae. Messaging that emphasizes concrete, personal benefits, such as nutrient density, heart health, or functional properties, performs better than abstract sustainability framings alone. The review also notes that transparency, familiarity-building, and norm-based messaging improve consumer trust. Product category also matters: consumers are more receptive when microalgae appear in products where natural colors or added nutrients are expected, such as smoothies or baked goods.
Future directions
Olsen et al. argue that future advances depend on coordinated efforts in sensory chemistry, innovation in processing, and consumer research. A more detailed understanding of the molecular drivers of off-flavors and color perception will support the development of cleaner ingredient profiles. Parallel work must address psychological factors, such as perceived naturalness and familiarity, to be effective. Integrating these scientific and perceptual insights will be essential for positioning microalgae as truly mainstream ingredients.
Read the full review “Consumer acceptance of microalgae as a novel food – Where are we now? And how to get further“ in Physiologia Plantarum https://onlinelibrary.wiley.com/doi/10.1111/ppl.14337
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The regulatory revolution
-Rewiring cyanobacteria for a solar-powered future!
Efforts to engineer cyanobacteria began decades ago, sparking dreams of sun-powered factories. While early metabolic engineering focused on adding new pathways, low outputs persisted because the inherent regulatory circuits of the cell actively resisted the changes. In the 2010s, ‘regulatory engineering’ gained momentum as scientists discovered that subtle adjustments to the command centers of cells could lead to significant improvements in performance.
Cyanobacteria are wired for survival, constantly navigating drastic shifts in light and nutrients, this makes them poor factories. When scientists push for high production, the cells treat it as stress, triggering a regulatory backlash, leading to:
- Carbon allocation: Flux diverts from products to storage, such as glycogen piles that starve the biofuel pipeline (e.g., in isoprene producers).
- C/N imbalance: Perturbations of signaling metabolites such as 2-oxoglutarate, a central C/N signal, have been linked to dysregulated metabolism and reduced growth in engineered strains.
- Low flux: The photosynthetic engine idles, underusing its full horsepower.
Fixing it by tailoring the regulatory toolkit
Bolay et al. (2024) review how targeting sigma factors, small proteins, and metabolite sensors can rewire these circuits, making the green factories work in our favour.
The core strategy is to employ minor perturbations of regulatory mechanisms to achieve wide-ranging, advantageous effects on metabolism. The review details how targeting three fundamental classes of regulators can effectively rewire these circuits:
Sigma factors: Global transcriptional initiators that orchestrate coordinated expression of gene cohorts in response to stress or environmental transitions.
Transcriptional regulators: Effector-responsive controllers (e.g., 2-oxoglutarate-sensing LysR-type regulators) that modulate flux through expansive metabolic modules.
Small proteins: Rapid post-translational modifiers that dynamically adjust enzyme activity and metabolic throughput.
Future translational impact
The convergence of this detailed regulatory knowledge with rapidly advancing synthetic biology tools, such as CRISPR-Cas systems, marks the next evolutionary phase of cyanobacterial metabolic engineering. The strategic pivot from optimizing individual enzymes to the rational design of regulatory networks is the necessary step to unlock the full photosynthetic capacity of cyanobacteria. This strategic overhaul promises to translate their vast potential into cost-effective, scalable, and genuinely sustainable bioproduction platforms.
Read the full review “Tailoring regulatory components for metabolic engineering in cyanobacteria“ in Physiologia Plantarum https://onlinelibrary.wiley.com/doi/10.1111/ppl.14316
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The metabolome revolution
– Unlocking plant immunity with chemistry!
The foundation for modern metabolomics was laid in 1966 when Dalgliesh first employed Gas Chromatography–Mass Spectrometry (GC-MS) to analyse metabolites in biological extracts. This led to the initial metabolite fingerprinting data in the early 1970s, culminating in the proposal of the term “metabolomics” in 1998, which established its conceptual link with genetics and other omics fields. Research quickly expanded, and the current applications are broad.
Metabolomics now provides qualitative and quantitative insights across biological scales, from cell types to organs. The technique is crucial for identifying metabolite biomarkers, elucidating gene function, and characterising metabolic responses in key areas of plant biology, including growth, development, nutrient efficiency, and environmental stress tolerance.
Crop plants are highly susceptible to diverse biotic stresses, including viruses, pathogens and pests, resulting in significant global yield loss. From bacterial invasion to herbivore attack, plants reprogram their metabolism to mobilise both primary energy pathways and specialised defence metabolites such as phenolics, terpenoids, and alkaloids, the core of their chemical shield. However, the majority of defence-related plant metabolites remain unknown. Only a few attempts have been made to study metabolic reconfiguration that occurs during plant–pathogen/plant–pest interactions.
Kumari et al. (2024) address this gap by covering recent developments in metabolomics during biotic stresses, focusing on their significance in pathogen infection and herbivory, while also discussing current profiling techniques.
🧪The chemical language of defence
Metabolites are not passive by-products; they act as molecular messengers that modulate gene expression, activate defence pathways and coordinate systemic responses. Compounds such as salicylic acid, jasmonates, and ethylene orchestrate cross-talk between local and systemic immunity. Recent studies reveal how even subtle shifts in chemical cues reprogram the entire defence networks, linking metabolic flux directly to immunity.
🔄 Metabolic reprogramming
When attacked, plants rapidly remodel primary and secondary metabolism. Primary metabolites are diverted from growth toward defence-related biosynthesis. This metabolic rewiring provides precursors for secondary compounds, while also fuelling ROS and phytoalexin production. Metabolomic fingerprints distinguish the strategies plants deploy against different enemies: biotrophic pathogens trigger salicylic acid-dependent pathways, necrotrophs invoke jasmonate/ethylene signalling, and herbivory induces a suite of volatiles that recruit natural predators.
⚡The energy battleground
Defence demands energy, and invaders often exploit host metabolism for their own growth. Plants counter by reallocating carbon and ATP to fuel cell wall reinforcement, ROS production and stress-related protein synthesis. High-resolution metabolomics can track these shifts in glycolysis, the TCA-cycle, and amino acids, highlighting energy as a central battleground in plant-pathogen interactions.
🛡️The core chemical shield
Plants deploy an arsenal of secondary metabolites, including phenolics, terpenoids, alkaloids, and glucosinolates, which serve as toxins and signals. Phenylpropanoids fortify tissues and scavenge free radicals, while terpenoids and alkaloids deter pests. Targeted metabolomics enables mapping of these biosynthetic pathways, linking metabolite profiles to specific gene families and regulatory networks.
🔍Technology and profiling successes
No single technique can capture the full complexity of the metabolome. High-throughput approaches offer complementary insights into metabolite identity, abundance, and structure. Combining these with high-resolution Orbitrap or FT-ICR systems extends coverage to trace-level metabolites.The review highlights that integrating multiple platforms can uncover localised defence chemistry within tissues, such as the root–rhizosphere interface or pathogen entry points.
💻Computational translation of data
Transforming raw spectral data into biological insight relies on sophisticated bioinformatics and chemometric pipelines. Multivariate statistical tools help identify key metabolites correlated with resistance traits. Coupling metabolomic datasets with transcriptomics and proteomics provides a systems-level view of plant defence, bridging chemistry with gene regulation and signalling.
🌱Future translational impact
Next-generation methods, including spatial and single-cell metabolomics, combined with multi-omics integration, promise a deeper view of how defences are mobilised at cellular resolution. These approaches could guide breeding or engineering of metabolite-driven, stress-resilient crops.
Read the full review “Metabolomics-driven investigation of plant defense response against pest and pathogen attack” in Physiologia Plantarum https://onlinelibrary.wiley.com/doi/10.1111/ppl.14270
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The gas that saves crops
– Why H2S is the next big signal in stress biology
The minireview by Alvi et al. (2023) fundamentally advances our understanding of plant defense by highlighting reactive sulfur species (RSS)- especially hydrogen sulfide (H2S) – as key signaling molecules in abiotic stress tolerance. Long overshadowed by nitric oxide and reactive oxygen species, the sulfur network has emerged as a third pillar of cellular resilience, coordinating redox balance and defense signaling in stressed plants.
🧪 H2S: The chemistry of redox regulation
The power of H2S and its derivatives (persulfides, polysulfides) stems from the sulfur atom’s reactive thiol group.
- Signaling mechanism: RSS are produced from the amino acid cysteine and act through persulfidation — a reversible modification of target proteins that fine-tunes enzyme activity.
- Precision sensing: This reaction enables H₂S to act as a sensitive redox sensor, rapidly adjusting metabolism and antioxidant responses.
- Enzyme targets: By modifying key metabolic enzymes, RSS converts stress cues into quick biochemical and gene-level defense responses.
🛡️ The stress network: How RSS builds resilience
H₂S doesn’t act alone—it weaves into established defense pathways, serving as a master coordinator across multiple abiotic stress responses.
- Abiotic stress tolerance: H2S enhances plant tolerance against agricultural threats, including drought, salinity, and heavy metal toxicity by maintaining cellular homeostasis under duress.
- Antioxidant synergy: H2S acts together with glutathione (GSH) to keep the redox cycle running and neutralize ROS.
- Hormonal cross-talk: RSS signaling integrates with phytohormone networks, broadening the plant’s adaptive capacity.
🌱 Toward resilient crops
Understanding H₂S signaling offers new strategies for climate-smart agriculture. Targeting genes involved in its synthesis, such as cysteine synthase or D-cysteine desulfhydrase, could enhance antioxidant capacity and stress tolerance, paving the way for more resilient crop varieties.
Read the full review “The emerging key role of reactive sulfur species in abiotic stress tolerance in plants” in Physiologia Plantarum https://onlinelibrary.wiley.com/doi/10.1111/ppl.13945
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📢 Plants strike back:
When crops send a chemical S.O.S.
How do plants fight back when attacked by tiny sap-sucking invaders?
The Minireview by Karalija et al. (2023) dissects the fascinating chemistry behind a plant’s “cry for help” — a volatile-mediated defense system that enlists aphids’ own predators. As sessile organisms, plants can’t run or hide. Their survival depends on multi-layered defense strategies, both direct ones that strengthen tissues or produce toxins, and indirect ones that call for reinforcements.
This review focuses on an indirect defense – a tritropic alliance between plant, aphid and parasitic wasp.
🧪 The mechanism in brief:
The plant’s defense is not physical, but a highly specific molecular cascade triggered by minimal feeding damage
- Aphid attack triggers a volatile cocktail
Feeding causes minimal tissue damage but major stress through sap loss and virus spread.
- Plants respond chemically, not physically
They emit Herbivore-Induced Plant Volatiles (HIPVs), a tailored blend of terpenoids and phenylpropanoids that signal danger.
- The signaling hubs
Glandular trichomes act as tiny chemical factories, storing and releasing these defensive volatiles.
- The pathways
Aphid feeding activates the octadecanoid pathway, leading to a surge in jasmonic acid (JA). JA acts as the key endogenous signal, triggering the expression of downstream defense genes responsible for HIPV synthesis.
- The counterstrike
The distinct HIPV blend attracts parasitic wasps (mainly Aphidiinae) to the scene. The wasps use these olfactory cues to locate the infected plant and lay their eggs inside aphids, thereby cutting infestations at their source.
Why this matter for future agriculture
The complexities of this chemical dialogue are exacerbated by climate change, which accelerates aphid development and increases infestation rates. Therefore, harnessing this chemical ecology holds immense promise for developing sustainable and effective crop protection strategies.
Understanding these plant signals is not just a matter of fundamental ecology; it is a critical step toward sustainable pest control. The review emphasizes that further research into these exact signaling pathways is vital for identifying potential applications of these molecules—HIPVs and their precursors, such as terpenoids—in future integrated approaches to aphid control. This includes the possibility of genetically manipulating pathways to enhance the plant’s ability to attract allies and “strike back”.
Read the full review: “Plants strike back: Plant volatiles and their role in indirect defense against aphids” in Physiologia Plantarum.
https://onlinelibrary.wiley.com/doi/10.1111/ppl.13850
Also note that this article is part of the Special Issue “From the biosynthesis of volatiles and colors to their role in ecoenvironments.”
https://onlinelibrary.wiley.com/doi/toc/10.1111/(ISSN)1399-3054.SI-FLO
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