Biology subjects

Cvetkovska, M.

Publications and source records attributed to Cvetkovska, M..

7 recordsLinked to original sources

bioRxiv2026

Light spectral quality alters glandular trichome architecture more strongly than cannabinoid accumulation in Cannabis sativa

The glandular trichomes in Cannabis sativa, found predominantly on female flowers, produce and store a variety of unique phytocannabinoids, increasingly studied for their use in medicinal applications. Maximizing yield and cannabinoid profiles requires the optimization of the environmental factors that regulate plant growth. Light plays a prominent role, both as an energy source but also as an important developmental signal. Thus, optimization of lighting strategies, particularly through customizable light-emitting diode (LED) fixtures, has become a major focus of controlled-environment cannabis research. Here, we focus on the effect of blue-enriched and far red-enriched light spectra on the morphological traits and biochemical profiles of two THCA-dominant varieties: Pineapple Cough and Rocky Fire #7. Spectral composition exerts modest and genotype-specific effects on the plant development, inflorescence biomass, and cannabinoid concentration but we demonstrate a positive correlation between total yield and plant height in both varieties, regardless of spectra. We also show that growth under far-red enriched light affects the visible pigmentation in both varieties with significantly lower chlorophyll levels and paler fan and sugar leaves. Finally, we demonstrate that far-red light consistently increased the trichome stalk length in both varieties, suggesting that spectral composition can alter trichome development and morphology. Our data offers insights into cannabis development and secondary chemical profiles in response to different light spectra, allowing growers to adjust light spectra to obtain desirable cannabis traits for industrial production.

Plant Biology↗

bioRxiv2026

Temperature stress resilience in polar Chlamydomonas is regulated by acclimation to light and salinity: implications for survival in a changing world

O_LIAquatic algae are key primary producers in the Arctic and Antarctic, yet how cold-water species respond to environmental change is poorly understood. The Polar Regions are increasingly exposed to frequent heat waves, leading to declining ice cover, increased light availability, and decreasing salinity in polar waters. We compared three phylogenetically related but geographically distant polar Chlamydomonas species to test how habitat history shapes algal responses to light, salinity, and temperature stress. C_LIO_LIWe assessed the growth, morphology, and photochemistry of psychrophilic Chlamydomonas acclimated to native-like (lower light, higher salinity) and climate-shifted conditions (higher light, lower salinity). Next, we exposed acclimated cultures to a lethal heat shock and observed how acclimation affects algal temperature stress resilience. C_LIO_LIAll three species acclimated to climate-shifted conditions grew rapidly but showed the greatest sensitivity to temperature stress, with rapid loss of viability and photosynthetic efficiency. In contrast, slow-growing cultures acclimated to native-like conditions exhibited significantly greater resilience to temperature stress. C_LIO_LIOur work is the first to directly link light and salinity acclimation with temperature resilience in psychrophilic algae, suggesting that fast-growing polar green algae may be particularly vulnerable to increasingly frequent heat waves, with major implications for primary productivity in polar environments. C_LI

plant biology↗

bioRxiv2025

A Suite of Stains: Characterization of four fluorophores as complementary tools for visualizing neutral lipids in an extremophilic green alga

Understanding lipid metabolism in algae is critical to advancing our knowledge on fundamental algal physiology and for harnessing these organisms as platforms for the sustainable production of high-energy lipids. BODIPY is the most prevalently used fluorescent dye for the visualization of lipid droplets (LDs) in algae; however, its limitations warrant exploration of alternatives. Here we evaluate and compare four lipophilic fluorophores (BODIPY, DAF, Cou, DPAS) for their effectiveness in staining LDs in the extremophilic green alga Chlamydomonas priscui. We assess each dyes photophysical properties, synthetic accessibility, LD specificity, cellular toxicity, and suitability for microscopy and flow cytometry. All four dyes successfully stain LDs, but their performance diverges under different experimental conditions. BODIPY permits long-term incubation allowing quantification in time-course studies but exhibits poor LD specificity and high susceptibility to photobleaching. DAF enables polarity-sensitive staining but is highly toxic on prolonged exposure or during cellular stress. Cou and DPAS yield strong LD-specific signals with low cytotoxicity, making them ideal for studies involving environmental stress. However, DPAS requires room-temperature incubation, pointing toward greater potential utility for non-extremophilic algae. These results expand the toolbox for lipid biotechnology research in extremophiles and underscore the importance of tailoring dye selection and experimental conditions to algal physiology.

plant biology↗

bioRxiv2025

Duplications in the Chlorophyll a oxygenase (CAO) gene across the Viridiplantae

Viridiplantae, a diverse group of green plants and alga that have evolved from a common ancestor, are unified in their ability to produce and use two types of chlorophyll (chlorophyll a and chlorophyll b) to capture light energy. In addition to playing a role in light harvesting, chlorophyll b is required at the appropriate level for the accumulation, assembly, and stability of light harvesting complexes within the photosynthetic apparatus. Chlorophyll b is synthesized from chlorophyll a by the enzyme chlorophyllide a oxygenase (CAO), a Rieske-type mononuclear non-heme iron oxygenase. A regulatory degron sequence, described in detail only in land plants, regulates the stability of CAO proteins based on the availability of chlorophyll b. Recent identification of CAO gene duplication in bryophyte and green algal species, combined with expanded availability of sequenced genomes within the Viridiplantae, prompted further investigation into the role of gene duplication in the evolution of chlorophyll b biosynthesis. Examination of genomes from 246 plant and algae species revealed independently occurring CAO duplications throughout the Viridiplantae, with a higher prevalence of duplication in land plants compared to their algal relatives. Additionally, we demonstrate that the degron sequence is poorly conserved in chlorophytes, but first appears as a conserved sequence in charophytes, and is very highly conserved among the embryophytes. The evolutionary history and functional role of CAO throughout the Viridiplantae lineage is discussed based on these key observations, adding to our understanding of chlorophyll b biosynthesis and the role of CAO in photosynthetic species.

plant biology↗

bioRxiv2024

Light quality affects chlorophyll biosynthesis and photosynthetic performance in Antarctic Chlamydomonas

The perennially ice-covered Lake Bonney in Antarctica has been deemed a natural laboratory for studying life at the extreme. Photosynthetic algae dominate the lake food webs and are adapted to a multitude of extreme conditions including perpetual shading even at the height of the austral summer. Here we examine how the unique light environment in Lake Bonney influences the physiology of two Chlamydomonas species. Chlamydomonas priscuii is found exclusively in the deep photic zone where is receives very low light levels biased in the blue part of the spectrum (400-500 nm). In contrast, Chlamydomonas sp. ICE-MDV is represented at various depths within the water column (including the bright surface waters), and it receives a broad range of light levels and spectral wavelengths. The close phylogenetic relationship and psychrophilic character of both species makes them an ideal system to study the effects of light quality and quantity on chlorophyll biosynthesis and photosynthetic performance in extreme conditions. We show that the shade-adapted C. priscuii exhibits a decreased ability to accumulate chlorophyll and severe photoinhibition when grown under red light compared to blue light. These effects are particularly pronounced under red light of higher intensity, suggesting a loss of capability to acclimate to varied light conditions. In contrast, ICE-MDV has retained the ability to synthesize chlorophyll and maintain photosynthetic efficiency under a broader range of light conditions. Our findings provide insights into the mechanisms of photosynthesis under extreme conditions, and have implications on algal survival in changing conditions of Antarctic ice-covered lakes.

plant biology↗

bioRxiv2023

Aberrant light sensing and motility in the green alga Chlamydomonas priscuii from the ice-covered Antarctic Lake Bonney

The Antarctic green alga Chlamydomonas priscuii is an obligate psychrophile and an emerging model for photosynthetic adaptation to extreme conditions. Endemic to the ice-covered Lake Bonney, this alga thrives at highly unusual light conditions characterized by very low light irradiance (<15 mol m-2 s-1), a narrow wavelength spectrum enriched in blue light, and an extreme photoperiod. Genome sequencing of C. priscuii exposed an unusually large genome, with hundreds of highly similar gene duplicates and expanded gene families, some of which could be aiding its survival in extreme conditions. In contrast to the described expansion in the genetic repertoire in C. priscuii, here we suggest that the gene family encoding for photoreceptors is reduced when compared to related green algae. This alga also possesses a very small eyespot and exhibits an aberrant phototactic response, compared to the model Chlamydomonas reinhardtii. We also investigated the genome and behaviour of the closely related psychrophilic alga Chlamydomonas sp. ICE-MDV, that is found throughout the photic zone of Lake Bonney and is naturally exposed to higher light levels. Our analyses revealed a photoreceptor gene family and a robust phototactic response similar to those in the model Chlamydomonas reinhardtii. These results suggest that the aberrant phototactic response in C. priscuii is a result of life under extreme shading rather than a common feature of all psychrophilic algae. We discuss the implications of these results on the evolution and survival of shade adapted polar algae.

plant biology↗

bioRxiv2019

Chlamydomonas sp. UWO241 exhibits high cyclic electron flow and rewired metabolism under high salinity

The Antarctic green alga Chlamydomonas sp. UWO241 (UWO241) was isolated from the deep photic zone of a permanently Antarctic ice-covered lake. Adaptation to permanent low temperatures, hypersalinity, and extreme shade has resulted in survival strategies in this halotolerant psychrophile. One of the most striking phenotypes of UWO241 is an altered photosystem I (PSI) organization and constitutive PSI cyclic electron flow (CEF). To date, little attention has been paid to CEF during long-term stress acclimation and the consequences of sustained CEF in UWO241 are not known. In this study, we combined photobiology, proteomics, and metabolomics to understand the underlying role of sustained CEF in high salinity stress acclimation. High salt-grown UWO241 exhibited increased thylakoid proton motive flux and an increased capacity for NPQ. A Bestrophin-like Cl- channel was identified in the whole cell proteomes and transcriptome of UWO241 which likely supports ion homeostasis during high transthylakoid pH. Under high salt, a significant proportion of the upregulated enzymes were associated with the Calvin Benson Bassham Cycle (CBB), secondary metabolite biosynthesis, and protein translation. Two key enzymes of the Shikimate pathway, DAHP synthase and chorismate synthase, were also upregulated, as well as indole-3-glycerol phosphate synthase, an enzyme involved in biosynthesis of L-tryptophan and indole acetic acid. In addition, several compatible solutes (glycerol, proline and sucrose) accumulated to high levels in high salt-grown UWO241 cultures. We suggest that UWO241 maintains constitutively high CEF with associated PSI-cytb6f supercomplex to support robust growth and strong photosynthetic capacity under a constant growth regime of low temperatures and high salinity.

plant biology↗