Carotenoid Synthesis Research Articles

Two haplotype-resolved genome assemblies for AAB allotriploid bananas provide insights into banana subgenome asymmetric evolution and Fusarium wilt control

Bananas (Musa spp.) are one of the world’s most important fruit crops and play a vital role in food security for many developing countries. Most banana cultivars are triploids derived from inter- and intraspecific hybridizations between the wild diploid ancestor species Musa acuminate (AA) and M. balbisiana (BB). We report two haplotype-resolved genome assemblies of the representative AAB-cultivated types, Plantain and Silk, and precisely characterize ancestral contributions by examining ancestry mosaics across the genome. Widespread asymmetric evolution is observed in their subgenomes, which can be linked to frequent homologous exchange events. We reveal the genetic makeup of triploid banana cultivars and verify that subgenome B is a rich source of disease resistance genes. Only 58.5% and 59.4% of Plantain and Silk genes, respectively, are present in all three haplotypes, with >50% of genes being differentially expressed alleles in different subgenomes. We observed that the number of upregulated genes in Plantain is significantly higher than that in Silk at one-week post-inoculation with Fusarium wilt tropical race 4 (Foc TR4), which confirms that Plantain can initiate defense responses faster than Silk. Additionally, we compared genomic and transcriptomic differences among the genes related to carotenoid synthesis and starch metabolism between Plantain and Silk. Our study provides resources for better understanding the genomic architecture of cultivated bananas and has important implications for Musa genetics and breeding.

Novel transcriptome networks are associated with adaptation of capsicum fruit development to a light-blocking glasshouse film.

Light-blocking films (LBFs) can contribute to significant energy savings for protected cropping via altering light transmitting, such as UVA, photosynthetically active radiation, blue and red spectra affecting photosynthesis, and capsicum yield. Here, we investigated the effects of LBF on orange color capsicum (O06614, Capsicum annuum L.) fruit transcriptome at 35 (mature green) and 65 (mature ripe) days after pollination (DAP) relative to untreated control in a high-technology glasshouse. The results of targeted metabolites showed that LBF significantly promotes the percentage of lutein but decreased the percentage of zeaxanthin and neoxanthin only at 35 DAP. At 35 DAP, fruits were less impacted by LBF treatment (versus control) with a total of 1,192 differentially expressed genes (DEGs) compared with that at 65 DAP with 2,654 DEGs. Response to stress and response to light stimulus in biological process of Gene Ontology were found in 65-DAP fruits under LBF vs. control, and clustering analysis revealed a predominant role of light receptors and phytohormone signaling transduction as well as starch and sucrose metabolism in LBF adaptation. The light-signaling DEGs, UV light receptor UVR8, transcription factors phytochrome-interacting factor 4 (PIF4), and an E3 ubiquitin ligase (COP1) were significantly downregulated at 65 DAP. Moreover, key DEGs in starch and sucrose metabolism (SUS, SUC, and INV), carotenoid synthesis (PSY2 and BCH1), ascorbic acid biosynthesis (VTC2, AAO, and GME), abscisic acid (ABA) signaling (NCED3, ABA2, AO4, and PYL2/4), and phenylpropanoid biosynthesis (PAL and DFR) are important for the adaptation of 65-DAP fruits to LBF. Our results provide new candidate genes for improving quality traits of low-light adaptation of capsicum in protected cropping.

CONTENT OF PHOTOSYNTHETIC PIGMENTS IN LEAVES OF THE GENUS ACER L. SPECIES IN URBAN ENVIRONMENT

Background. Pigment concentration is a species trait, and is an integral indicator of adaptive response to changes in environmental factors and the growing conditions. The intensive development of modern cities imposes certain requirements on the selection of plants for landscaping, one of which is a high level of adaptive responses.
 Purpose. The purpose of this study was to determine the content of photosynthetic pigments in the leaves of the genus Acer species in urban conditions of the city of Maуkop, the Adygea Republic.
 Materials and methods. We used the spectrophotometric method to determine the content of photosynthetic pigments in the leaves of the genus Acer L. species: A. platanoides, A. pseudoplatanus, A. saccharinum, A. negundo, A. campestre in an urban environment of the city of Maуkop and the zone of conditional control (Botanical garden). We carried out statistical processing of experimental data by using the MS Excel 2010 package.
 Results. We have revealed that in the conditions of an urbanized environment the total content of chlorophylls is 1.1-2.2 times higher in comparison with that of the zone of control. Taking into account the level of variability of the total content of green pigments in the city, we arranged the studied species in the following order: A. saccharinum A. campestre ˂ A. pseudoplatanus ˂ A. platanoides ˂ A. negundo. The ratio of the amount of chlorophylls to carotenoids reacted very sensitively to the impact of urban environmental factors. A. campestre and A. saccharinum differed from A. negundo, A. pseudoplatanus, and A. platanoides for this indicator.
 Conclusion. The study made allow us to state that in the conditions of an urbanized environment, the studied species of the genus Acer undergo restructuring in the structure of pigment complexes. An increase in the synthesis of chlorophylls and carotenoids raises their adaptive capabilities to the negative impact of urban environmental factors.

The sensor histidine kinase (SLN1) and acetyl-CoA carboxylase (ACC1) coordinately regulate the response of Neurospora crassa to the springtail Sinella curviseta (Collembola: Entomobryidae) attack.

Understanding the regulatory pathways by which fungi respond to environmental signals through interlinked genes provides insights into the interactions between fungi and insects. The coordinated optimization of the regulatory networks is necessary for fungi to adapt to their habitats. We demonstrated that the synergistic regulation of sensor histidine kinase (SLN1) and acetyl-CoA carboxylase (ACC1) plays a critical role in regulating the fungal response to Sinella curviseta stress. Furthermore, we found that the enhanced production of trehalose, carotenoids, and 5-MTHF plays crucial role in the resistance to the fungivore. Our results provide insights into the understanding of the adaptation of N. crassa to environmental stimuli.

Effect of nano-calcium on carotenoid and anthocyanin contents of nectarine fruit

Increasing the carotenoid content of nectarine (Prunus persica var. nucipersica) is of great significance for improving its quality and economic value. A two years study was carried out on ‘Shuguang’ nectarine to evaluate the effect of calcium chloride (Cl–Ca) and L-aspartic acid nano calcium [Ca (L-asp) - NPs] (nano-Ca) on carotenoid accumulation. The results show that both Cl–Ca and nano-Ca could increase the carotenoid content of nectarine fruit flesh, but the effect of nano-Ca was more significant. Nano-Ca is more easily absorbed by nectarine leaves and fruits, which improves the calmodulin activity of leaves, peel and flesh, and up-regulates the expression of carotenoid synthesis-related genes PpPSY, PpPDS, PpZDS, PpLCY-B, PpCHY-B and PpZEP. Nano-Ca also significantly up-regulated the expression of sucrose synthesis related genes PpSUS1 and PpSUS3 in leaves and sucrose transport related genes PpSUT2 and PpSUT4 in stem phloem, promoting the transport of more photosynthetic products to fruits, providing raw materials for carotenoid synthesis, and increasing the content of total sugars and ascorbic acid (Vc). In addition, nano-Ca can also up-regulate the expression levels of PpMYB10.1 and PpUFGT and promote total anthocyanins accumulation in peel. The results of our study will be useful for clarifying how nano-fertilizer improve the fruit quality of nectarine.

Overexpression of a pseudo-etiolated-in-light-like protein in Taraxacum koksaghyz leads to a pale green phenotype and enables transcriptome-based network analysis of photomorphogenesis and isoprenoid biosynthesis.

Plant growth and greening in response to light require the synthesis of photosynthetic pigments such as chlorophylls and carotenoids, which are derived from isoprenoid precursors. In Arabidopsis, the pseudo-etiolated-in-light phenotype is caused by the overexpression of repressor of photosynthetic genes 2 (RPGE2), which regulates chlorophyll synthesis and photosynthetic genes. We investigated a homologous protein in the Russian dandelion (Taraxacum koksaghyz) to determine its influence on the rich isoprenoid network in this species, using a combination of in silico analysis, gene overexpression, transcriptomics and metabolic profiling. Homology-based screening revealed a gene designated pseudo-etiolated-in-light-like (TkPEL-like), and in silico analysis identified a light-responsive G-box element in its promoter. TkPEL-like overexpression in dandelion plants and other systems reduced the levels of chlorophylls and carotenoids, but this was ameliorated by the mutation of one or both conserved cysteine residues. Comparative transcriptomics in dandelions overexpressing TkPEL-like showed that genes responsible for the synthesis of isoprenoid precursors and chlorophyll were downregulated, probably explaining the observed pale green leaf phenotype. In contrast, genes responsible for carotenoid synthesis were upregulated, possibly in response to feedback signaling. The evaluation of additional differentially expressed genes revealed interactions between pathways. We propose that TkPEL-like negatively regulates chlorophyll- and photosynthesis-related genes in a light-dependent manner, which appears to be conserved across species. Our data will inform future studies addressing the regulation of leaf isoprenoid biosynthesis and photomorphogenesis and could be used in future breeding strategies to optimize selected plant isoprenoid profiles and generate suitable plant-based production platforms.

Blue light induces leaf color change by modulating carotenoid metabolites in orange-head Chinese cabbage (Brassica rapa L. ssp. pekinensis)

Carotenoids are involved in the formation of plant leaf color as well as photosystem photoprotection. This study showed that blue light significantly induced up-regulation of the total carotenoid content in the inner leaves of orange-head Chinese cabbage (OHCC). Furthermore, the transcriptomic analysis revealed that blue light treatment induced up-regulation of genes in photosynthesis (BrHY5-2, BrCOP1 and BrDET1) and the methylerythritol 4-phosphate pathways (BrGGPS, BrDXS and BrHDR) upstream of the carotenoid metabolic pathway. Carotenoid metabolomic analysis revealed that the accumulation of several orange and red carotenoids (lycopene, zeaxanthin, β-carotene, lutein, and β-cryptoxanthin) after blue light treatment contributed to the deepening of the leaf coloration, suggesting that short-term blue light treatment could be used to boost nutritional quality. The light signal gene BrHY5-2 participated in the blue light-induced transcriptional regulation of carotenoid biosynthesis in OHCC. Overexpression of BrHY5-2 in Arabidopsis significantly increased the total carotenoid content and the sensitivity to blue light. The above findings revealed new insights about blue-light-induced carotenoid synthesis and accumulation in OHCC lines. They suggested a new engineering approach to increase the nutritional value of vegetables.

Establishment of genetic transformation system of peach callus

Peach (Prunus persica L. Batsch) is an economically important fruit in the Rosaceae family and is favored by consumers for its nutritional value. Genetic transformation is an important way to carry out genetic improvement of peaches and to conduct functional genomics studies. Although many strategies to transform peach have been attempted, there are only a few successful examples. Here we conducted genetic transformation experiments using the peach anther-derived calli from four genotypes and found that ‘ZJB’ peach callus is a unique recipient material for genetic transformation. Based on this, we developed an effective genetic transformation system of peach callus, through transforming carotenoid synthesis genes, RUBY, and GFP, respectively. The present research indicated that this peach callus transformation system exhibits well engineered manipulation capacity for carotenoid and betalain-related metabolites. The present callus genetic transformation system will provide a crucial tool for gene function analysis and bioengineering research in peach.

Industrially significant biomolecules from recently discovered haloalkaliphiles, inhabitants of the coastal mangrove vegetation in Bordi, India

The coastal Arabian Sea area near Bordi, Maharashtra, India is one of the natural places for mangrove vegetation. This sampling site has been explored for the first time, and to the best of our knowledge, no other researchers have conducted scientific research on the same site prior to this. Water samples from the rhizosphere of the mangrove Avicennia marina were collected and physicochemical examination revealed that the water samples were of saline-alkaline quality. The haloalkaliphiles were isolated by using different microbiological media and characterized by polyphasic approach. Further, the isolates were identified by 16 S rRNA partial gene sequencing and MEGA version 11, a public domain was used for the evolutionary studies. The production of industrially important hydrolytic enzymes amylase, lipase, and protease were optimized in submerged fermentation media using efficient isolates via the OVAT approach, and the enzymes were found to be alkali and salt stable. The carotenoid producer, Planococcus plakortidis BMS5, was deposited at N.C.M.R., Pune, India under accession number MCC5186. The synthesis of carotenoids by Planococcus plakortidis BMS5 was carefully investigated. Thin layer chromatography, UV–VIS spectroscopy, and GC-MS were used to characterise the carotenoids. The hydrolytic enzymes produced by the efficient isolates exhibited great activity and stability over a wide pH (7−12) and temperature (20–50 oC) range. Furthermore, at 10–15% salt, the hydrolytic enzymes were the most stable. The carotenoids produced by haloalkaliphiles were discovered to have antioxidant characteristics and could be exploited in the food and pharmaceutical industries. The haloalkaliphiles' hydrolytic enzymes have the potential to be used in the development of new medicinal formulations. Overall, this study illustrates the potential of employing microbes from extreme environments to produce useful bioactive chemicals with a variety of applications in diverse industries.

Comparative transcriptomic and plastid development analysis sheds light on the differential carotenoid accumulation in kiwifruit flesh.

Carotenoids are colorful lipophilic isoprenoids synthesized in all photosynthetic organisms which play roles in plant growth and development and provide numerous health benefits in the human diet (precursor of Vitamin A). The commercially popular kiwifruits are golden yellow-fleshed (Actinidia chinensis) and green fleshed (A. deliciosa) cultivars which have a high carotenoid concentration. Understanding the molecular mechanisms controlling the synthesis and sequestration of carotenoids in Actinidia species is key to increasing nutritional value of this crop via breeding. In this study we analyzed fruit with varying flesh color from three Actinidia species; orange-fleshed A. valvata (OF), yellow-fleshed A. polygama (YF) and green-fleshed A. arguta (GF). Microscopic analysis revealed that carotenoids accumulated in a crystalline form in YF and OF chromoplasts, with the size of crystals being bigger in OF compared to YF, which also contained globular substructures in the chromoplast. Metabolic profiles were investigated using ultra-performance liquid chromatography (UPLC), which showed that β-carotene was the predominant carotenoid in the OF and YF species, while lutein was the dominant carotenoid in the GF species. Global changes in gene expression were studied between OF and GF (both tetraploid) species using RNA-sequencing which showed higher expression levels of upstream carotenoid biosynthesis-related genes such as DXS, PSY, GGPPS, PDS, ZISO, and ZDS in OF species compared to GF. However, low expression of downstream pathway genes was observed in both species. Pathway regulatory genes (OR and OR-L), plastid morphology related genes (FIBRILLIN), chlorophyll degradation genes (SGR, SGR-L, RCCR, and NYC1) were upregulated in OF species compared to GF. This suggests chlorophyll degradation (primarily in the initial ripening stages) is accompanied by increased carotenoid production and localization in orange flesh tissue, a contrast from green flesh tissue. These results suggest a coordinated change in the carotenoid pathway, as well as changes in plastid type, are responsible for an orange phenotype in certain kiwifruit species.

The influence of spermidine on the build-up of fucoxanthin in Isochrysis sp. Acclimated to varying light intensities

Spermidine is a type of important growth regulator, which involved in the biosynthesis of photosynthetic pigments, and has the function of promoting cell proliferation. In this study, Isochrysis sp. was selected as the research object to explore the effects of spermidine supplementation on the growth of algal cells and fucoxanthin synthesis under different light intensities. The results showed that the cell density (5.40 × 106 cells/mL) of algae were the highest at 11 days under the light intensity of 200 μmol·m−2·s−1 and spermidine content of 150 μM. The contents of diadinoxanthin (1.09 mg/g) and fucoxanthin (6.11 mg/g) were the highest when spermidine was added under low light intensity, and the growth of algal cells and fucoxanthin metabolism were the most significant. In the carotenoid synthesis pathway, PDS (phytoene desaturase) was up-regulated by 1.96 times and VDE (violaxanthin de-epoxidase) was down-regulated by 0.95 times, which may promote fucoxanthin accumulation.

Microscopic Raman study of fungal pigment using the genetically amenable rock inhabitant Knufia petricola as a model organism

Fungal pigments such as melanin and carotenoids are distinctive markers of animal and plant pathogenic fungi as well as their environmental relatives. These complex pigments play important roles in pathogenicity and stress tolerance while also being useful as biomarkers. Accordingly, it is important to be able to identify in situ the pigments in black fungi, a group of clinical and environmental importance. In this study, wild-type and genetically modified strains of Knufia petricola A95 and wild fungal cells attached to ancient rock were investigated for their spectroscopic and microscopic Raman features and morphological appearance. Knockout mutants of melanin synthesis genes pks1 (polyketide synthase), sdh1 (scytalone dehydratase), and both pks1 and the carotenoid synthesis gene phd1 (phytoene desaturase) were studied We applied two different Raman microscopes using two lasers, with 633 nm and 488 nm wavelengths. We analyzed and compared Raman spectra between the measured reference substances and the mutant and wild-type strains. In the wild strain WT:A95, the peaks close to melanin peals were found at 1353 cm−1 and 1611 cm−1. There are no characteristic melanin peaks at 1580–1600 cm−1 and around 1350 cm−1 at the spectrum of the Δpks1/Δphd1 mutant and the Δsdh1 mutant. The Δpks1 mutant spectrum has the peaks at the beta-carotene v2 C-C in-plane stretch at 1155 cm−1 and v3 C-CH3 deformation at 1005 cm−1. The peaks of carotenoids and melanin were found in all mutants and the wild strain, except the Δpks1/Δphd1 mutant. Raman spectra allow for discrimination between the various pigments. Hence, interactions between natural fungal melanin, as well as other protective pigments, and complex environmental matrices can be characterized on a range of spatial and temporal scales.

Characterization of C30 carotenoid and identification of its biosynthetic gene cluster in Methylobacterium extorquens AM1

Methylobacterium species, the representative bacteria distributed in phyllosphere region of plants, often synthesize carotenoids to resist harmful UV radiations. Methylobacterium extorquens is known to produce a carotenoid pigment and recent research revealed that this carotenoid has a C30 backbone. However, its exact structure remains unknown. In the present study, the carotenoid produced by M. extorquens AM1 was isolated and its structure was determined as 4-[2-O-11Z-octadecenoyl-β-glucopyranosyl]-4,4′-diapolycopenedioc acid (1), a glycosylated C30 carotenoid. Furthermore, the genes related to the C30 carotenoid synthesis were investigated. Squalene, the precursor of the C30 carotenoid, is synthesized by the co-occurrence of META1p1815, META1p1816 and META1p1817. Further overexpression of the genes related to squalene synthesis improved the titer of carotenoid 1. By using gene deletion and gene complementation experiments, the glycosyltransferase META1p3663 and acyltransferase META1p3664 were firstly confirmed to catalyze the tailoring steps from 4,4′-diapolycopene-4,4′-dioic acid to carotenoid 1. In conclusion, the structure and biosynthetic genes of carotenoid 1 produced by M. extorquens AM1 were firstly characterized in this work, which shed lights on engineering M. extorquens AM1 for producing carotenoid 1 in high yield.

Effects of salt stress and cooling regimes on the pigment composition of Dunaliella salina cells

Background: Microalgae are able to produce a significant amount of biologically significant substances. In connection with the growing popularity of microalgae, it is important to develop effective methods for storing cultures and creating strain banks. This will not only meet the needs of science and biotechnology for viable and sustainable crops, but will also solve the problem of biodiversity conservation. Objectives: study the effect of salt stress and cooling regimes on the pigment composition of microalgae Dunaliella salina cells in order to increase their safety after freezing-thawing. Materials and methods: The objects of the study were the unicellular green microalgae D. salina. Cultivation was carried out according to the standard method on nutrient media with different amounts of NaCl and trace elements. Adaptation to low temperatures was carried out by exposure of samples in the dark at temperature 4°C for 24 hours. Freezing was performed by placing 1 ml of the cell suspension in a 1.8 ml polypropylene cryogenic vial (Nunc, Sigma-Aldrich), cooled at a rate of 1 deg/min using a Mr. Frosty with following regimes: to -10°С, -40°С, -40°С followed by immersion to liquid nitrogen or direct immersion to liquid nitrogen (-196°С). Thawing was carried out in a water bath (37°С) with continuous shaking for 1–2 min. Microscopic examinations were carried out on an LSM-510 Meta laser scanning microscope (Carl Zeiss, Germany) upon excitation by a diode laser with a wavelength of 405 nm and 573 nm using a Nile Red stain. Results: It has been established that the formation of intracellular lipid globules and the synthesis of carotenoids in D. salina cells contribute to an increase in the concentration and number of motile cells after freezing-thawing. It has been shown that during rapid cooling, adaptive mechanisms do not have time to turn on in cells, and complete destruction of carotene-containing lipid globules occurs. Conclusions: Cryopreservation of D. salina cells should be carried out at a rate of 1 deg/min to -40°C, followed by immersion in liquid nitrogen and a mandatory stage of precultivation at 4°C for 24 hours. This approach allows the cells to adapt to a decrease in temperature, which contributes to the best result after freezing-thawing.

Transcriptomics and Metabolomics Reveal the Critical Genes of Carotenoid Biosynthesis and Color Formation of Goji (Lycium barbarum L.) Fruit Ripening.

Carotenoids in goji (Lycium barbarum L.) have excellent health benefits, but the underlying mechanism of carotenoid synthesis and color formation in goji fruit ripening is still unclear. The present study uses transcriptomics and metabolomics to investigate carotenoid biosynthesis and color formation differences in N1 (red fruit) and N1Y (yellow fruit) at three stages of ripening. Twenty-seven carotenoids were identified in N1 and N1Y fruits during the M1, M2, and M3 periods, with the M2 and M3 periods being critical for the difference in carotenoid and color between N1 and N1Y fruit. Weighted gene co-expression network analysis (WGCNA), gene trend analysis, and correlation analysis suggest that PSY1 and ZDS16 may be important players in the synthesis of carotenoids during goji fruit ripening. Meanwhile, 63 transcription factors (TFs) were identified related to goji fruit carotenoid biosynthesis. Among them, four TFs (CMB1-1, WRKY22-1, WRKY22-3, and RAP2-13-like) may have potential regulatory relationships with PSY1 and ZDS16. This work sheds light on the molecular network of carotenoid synthesis and explains the differences in carotenoid accumulation in different colored goji fruits.

Effect of Red Visible Lighting on Postharvest Ripening of Bananas via the Regulation of Energy Metabolism

The mechanism by which LED red light irradiation regulates postharvest banana ripening was evaluated in this study by the continuous irradiation of banana fruits at the mature-green stage. In this study, a self-developed LED banana fresh-keeping container lid was used to continuously irradiate the immature banana fruit. The light wavelength was 655.0 ± 1.0 nm, the light intensity was 800.0 ± 10.0 LX, and the height between the LED lamp and the fruit was 15.0 ± 0.5 cm. Bananas stored under dark conditions were used as the negative control group, and bananas stored under dark conditions after spraying with 500.0 mg/L ethephon diluent were used as the positive control group. Changes in physiological parameters related to postharvest banana ripening, such as the respiration rate, ethylene release, texture, color, carotenoid content, chlorophyll content, adenosine triphosphate content, and energy metabolism-related enzyme activities, were measured during 8 days of storage at 20.0 ± 0.1 °C to analyze the key factors determining postharvest banana ripening in response to red light. The red light-irradiated bananas had higher total color differences and higher rates of chlorophyll degradation and carotenoid synthesis than those of the ethephon-treated group during the storage period. Red light irradiation promoted banana fruit ripening and senescence mainly by promoting carotenoid synthesis, capturing absorbed light energy, accelerating energy metabolism, effectively enhancing the activities of the respiratory and energy metabolism-related enzymes H+ adenosine triphosphatase, Ca2+ adenosine triphosphatase, succinate dehydrogenase, cytochrome C oxidase, and malic enzyme, and promoting organic acid degradation. In conclusion, LED red light can be used as a new physical ripening technology for bananas, with a similar effect to that of traditional ethephon treatment.

Identification of a herbicide-resistant biotype of Echinochloa crus-galli in Ukraine

Ukraine is one of the world’s guarantors of food security and has the potential to further increase agricultural production. However, the vast majority of herbicides used on crops are acetolactate synthase (ALS) inhibitors, which poses a threat of herbicide-resistant weed species. The emergence and spread of herbicide-resistant weed biotypes can significantly increase the cost of growing crops to the point of loss of profitability. Herbicide resistance in barnyardgrass (Echinochloa crus-galli var. crus-galli) has been studied in long-term field and greenhouse experiments. Resistance of E. crus-galli to the ALS herbicide triazolopyrimidine derivative ‒ penoxsulam was identified. Expressed resistance was observed in weed plants grown from seeds collected under production conditions in Kherson region in 2015–2016 and 2020–2021. Cross resistance was observed for imidazolinone and sulfonylurea derivatives. It should be noted that the level of cross resistance to ALS herbicides was slightly higher for plants derived from weed seeds harvested in 2020–2021 compared to those harvested in 2015–2016. The introduction of a herbicidal composition of a herbicide mixture ‒ an inhibitor of 4-hydroxyphenylpyruvate dioxygenase (HPPD) (an enzyme in plants in the chain of carotenoid synthesis) ‒ mesotrione with an ALS-inhibitor (nicosulfuron) allowed effective control of the weed, which indicates the absence of multiple resistance to herbicides ‒ inhibitors of carotenoid synthesis. The high efficiency of E. crus-galli control was established by the application of herbicides ‒ inhibitors of fatty acid synthesis (graminicides). The highest level of efficiency in the experiments was observed with the application of fluazifop-butyl and somewhat less ‒ with pinoxaden. A tendency to reduce phytotoxicity to barnyardgrass from the south of Ukraine was observed with the introduction of tepraloxydim and quizalofop-ethyl. A lower level of phytotoxicity of fenoxaprop-p-ethyl on E. crus-galli should be noted compared to the effect of pinoxaden. No multiple resistance was observed with glyphosate (5-enolpyruvylshikimate-3-phosphate synthase inhibitor) and reglone (photosystem I inhibitor), allowing control of vegetative weeds at the beginning and end of the growing season. It has been established that monocot weed species have significantly increased their presence and harmfulness in agrophytocenoses in Ukraine and in the world since the 1950s with the widespread introduction of selective dicotyledonous species control with aryloxyphenoxyacetic, propionic and benzoic acid derivatives. This trend has been maintained until recently ‒ barnyardgrass is one of the dominant weed species in modern agrophytocenoses of Ukraine. Therefore, the identification of the ALS-resistant biotype of barnyardgrass complicates weed control in the following crops in rotations in the southern regions of the country: in maize crops with cross resistance to nicosulfuron, in sunflower ‒ to imidazolinones (imazamox, imazapyr), and also makes it impossible to use penoxsulam in rice production. Traditionally, the use of synthetic auxins, phenoxyacetic acid derivatives, etc. is used to control ALS-resistance. However, in Kherson region of Ukraine, already in the third year of application of rinskor (florpyrauxifen-benzyl), some weed plants were found on rice fields affected by ALS-resistant barnyardgrass, which recovered after the use of synthetic auxin. Therefore, the control of ALS-resistance (penoxsulam, etc.) in E. crus-galli with the application florpyrauxifen-benzyl in the Kherson region of Ukraine is already limited. An obvious and economically feasible preventive measure against the emergence of resistant weed biotypes is the implementation of GAP (Good Agricultural Practice, FAO) approaches: in particular, the use of high quality seeds without weed impurities, increasing the proportion of agrotechnical weed control measures, restoring and expanding crop rotations with mandatory rotation of herbicides with different modes of action, introducing dicotyledonous/leguminous crops into rotations, and using herbicides with different modes of action in crops separately or in mixtures. At the same time, agrotechnical measures and the preservation of biodiversity in agrophytocenoses should be the main factor in controlling resistance in weeds. The use of herbicides and their mixtures with different modes of action is of secondary importance. The identification of highly damaging ALS-resistant E. crus-galli in southern Ukraine indicates the insufficient effectiveness of weed control exclusively with herbicides with a single mechanism of action and requires a significant revision of the principles of crop rotation and ways of weed control in the country to maintain high levels of profitability and productivity of agrophytocenoses. Solving this problem is urgent for the preservation of Ukraine's potential as one of the guarantors of global food security.

Sunlight filtered via translucent-colored polyvinyl chloride sheets enhanced the light absorption capacity and growth of Arthrospira platensis cultivated in a pilot-scale raceway pond

In this research, the effects of filtered sunlight traveling through translucent-colored polyvinyl chloride (PVC) sheets on the photoconversion efficiency of Arthrospira platensis are investigated. Filtered sunlight improves the phycobilisome’s capacity to completely absorb and transport it to intracellular photosystems. Findings indicated that filtered sunlight via orange-colored PVC sheet increased biomass dry weight by 21% (2.80 g/L), while under blue-colored PVC sheet decreased by 32% (1.49 g/L), when compared with translucent-colored (control) PVC sheet (2.19 g/L) after 120 h of culture. The meteorological conditions during the 1st week of cultivation reported higher light flux than the subsequent weeks. Furthermore, sunlight filtered through orange PVC sheet enhanced protein, allophycocyanin, phycocyanin, chlorophyll-a and carotenoids synthesis by 13%, 15%, 13%, 22%, and 27%, respectively. This practical and inexpensive solar radiation filtration system supports large-scale production of tailored bioactive compounds from microalgae with high growth rate.

The Content of Carotinoid in the Fruits of Some Subtropical Plants

Key words: plant pigments, chlorophylls, fruit extract, wet weight, dry weight, pigment concentration Carotenoids are yellow, orange or red pigments, synthesized in the cells of bacteria, fungi and higher plants. Carotenoids are the most widespread group of plant pigments. A number of important functions are performed by carotenoids. As additional pigments, they absorb light energy and transfer it to chlorophyll Ca. The synthesis of carotenoids in plant tissues is more active in the dark, while in the light, it is suppressed. Carotenoids promote sexual maturation in the plant organism. During the flowering period, the amount of carotenoids partially decreases in the leaves, and increases in the stamens and petals. The studies were conducted on the fruits of the following subtropical plants: kiwi, actinidia (Actinidia deliciosa), banana (Musa), tangerine (Citrus reticulata), persimmon (Diospyros lotus L.). The concentration of pigments in these fruits was spectrophotometrically determined by measuring the optical density, which is considered a quantitative method for determining pigments. The optical density of the colors was determined using an SL150 spectrophotometer at a wavelength of 452.5 nm, and for chlorophyll at a wavelength of 663 nm and 644 nm. Studies have shown that the smallest values of concentration and content of carotenoids in the fruits of the investigated plants were observed in the banana pulp. It was found that the concentration and content of carotenoids, as well as the amount of chlorophyll Ca and Cb in tangerine and kiwi fruits are almost equal. The contents of chlorophylls and carotenoids in the fruits of the studied plants are inversely proportional: the higher the content of chlorophylls, the lower the number of carotenoids.

Comparative analysis of carotenoid synthesis and transcriptome of a microalga Chlorophyta MCH-35, potential lutein producer, in response to different quality light

Light plays an important role in the regulation of metabolic pathways related to photoprotection of the photosynthetic apparatus. The objective of our work was to evaluate in the microalga Chlorophyta MCH-35, isolated in the coastal desert of Antofagasta and potential producer of lutein, the influence of white, blue and red light, through LED technology, on the accumulation of carotenoids analyzed by HPLC and the associated molecular regulation mechanisms, through RNA-seq. The results showed that blue and white light stimulate carotenoid productivity with values close to 1.3 mg L−1 day−1, in contrast to red light (≈0.5 mg L−1 day−1), being lutein the main representative with values close to 0.3 % dry.wt. On the other hand, it was observed that blue light also induces the accumulation of other carotenoids such as astaxanthin, violaxanthin, β-carotene and zeaxanthin, relating this result to the up-regulation of 11 of the 12 detected transcripts related to key enzymes present in the pathway of biosynthesis of these pigments. Finally, it has been observed that light under wavelength stress treatments induce the regulation of transcripts involved in metabolic pathways related to photoprotection mechanisms in general. This study provided the bases for future research on metabolic regulation in microalgae cultures based on the implementation of light induction systems.