Search Results (43)

A previously undescribed cis-clerodane diterpenoid, diangelate solidagoic acid J (1), along with two known cis-clerodane diterpenoids, solidagoic acid C (2) and solidagoic acid D (3), as well as two known unsaturated monoacylglycerols, 1-linoleoyl glycerol (4) and 1-α-linolenoyl glycerol (5), were isolated and characterized from the n-hexane leaf extract of Solidago gigantea (giant goldenrod). Compounds 2–5 were identified first in this species, and compounds 4 and 5 are reported here for the first time in the Solidago genus. The bioassay-guided isolation procedure included thin-layer chromatography (TLC) coupled with a Bacillus subtilis antibacterial assay, preparative flash column chromatography, and TLC–mass spectrometry (MS). Their structures were elucidated via extensive spectroscopic and spectrometric techniques such as one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and high-resolution tandem mass spectrometry (HRMS/MS). The antimicrobial activities of the isolated compounds were evaluated by a microdilution assay. All compounds exhibited weak to moderate antibacterial activity against the Gram-positive plant pathogen Clavibacter michiganensis, with MIC values ranging from 17 to 133 µg/mL, with compound 5 being the most potent. Only compound 1 was active against Curtobacterium flaccumfaciens pv. flaccumfaciens, while compound 3 demonstrated a weak antibacterial effect against B. subtilis and Rhodococcus fascians. Additionally, the growth of B. subtilis and R. fascians was moderately inhibited by compounds 1 and 5, respectively. None of the tested compounds showed antibacterial activity against Gram-negative Pseudomonas syringae pv. tomato and Xanthomonas arboricola pv. pruni. No bactericidal activity was observed against the tested microorganisms. Compounds 2 and 3 displayed weak antifungal activity against the crop pathogens Bipolaris sorokiniana and Fusarium graminearum. Our results demonstrate the efficacy of bioassay-guided strategies in facilitating the discovery of novel bioactive compounds. Full article

Mycotoxins are synthesized by various fungal species and are known to exert toxic effects on vertebrates and other animals, even at low concentrations. However, the current countermeasure for mycotoxin contamination is random inspection of samples prior to shipment. In this study, we focused on Chlorella sorokiniana (CS) from Ishigaki Island, Japan, and examined its ability to detoxify deoxynivalenol (DON), ochratoxin A (OTA), and fumonisin B1 (FB1) in vitro and in vivo. The binding of CS to DON, OTA, and FB1 was evaluated in vitro. The detoxification of CS was demonstrated by monitoring its concentrations in the plasma and urine samples of male ICR mice. Plasma and urine samples were collected 30 min, 2 h, and 24 h after an oral administration of 5 mg/kg mycotoxins and/or 500 mg/kg CS. CS bound to more than 80% and 40% of DON and OTA, respectively, whereas the binding of CS to FB1 was less than 10%. The concentrations of DON and OTA in plasma and urine samples were substantially reduced by CS co-administration, whereas CS did not affect FB1 absorption. The co-administration of CS substantially inhibited the systemic absorption of DON and OTA. Full article

Microalgae represent promising biotechnological platforms for bioactive compound production with pharmaceutical applications. This study investigated the phytochemical composition and biological activities of lipid extracts from three Chlorella species to evaluate their potential as antioxidant and antidiabetic sources. Lipid extraction using chloroform–methanol (2:1) followed by GC–MS analysis revealed distinct compound distributions: 29 compounds in C. ellipsoidea, 33 in C. sorokiniana, and 19 in C. vulgaris. Major bioactive compounds included 2-hexanol, 1,3,6-heptatriene, 4-(2,3-dimethyl-2-cyclopenten-1-yl)-4-methylpentanal, n-hexadecanoic acid, and octadecanoic acid. Biological activity screening encompassed antioxidant assessment through DPPH• and •NO radical scavenging assays and FRAP analysis, while antidiabetic potential was evaluated using α-glucosidase and α-amylase inhibition assays. C. sorokiniana exhibited superior bioactivity with the highest antioxidant capacity (DPPH• IC₅₀ = 329.03 ± 4.30 µg/mL; •NO IC₅₀ = 435.53 ± 10.20 µg/mL; FRAP = 94.74 ± 5.72 mg TE/g) and strongest enzyme inhibition (α-glucosidase IC₅₀ = 752.75 ± 57.95 µg/mL; α-amylase IC₅₀ = 3458.50 ± 104.01 µg/mL). This is the first report on C. sorokiniana strain KU.B2′s biological properties and phytochemical profile. These findings establish C. sorokiniana as a valuable biotechnological platform for pharmaceutical bioactive compound development. Full article

Bacterial strain TSO55 was isolated from a commercial field of wheat (Triticum turgidum L. subsp. durum), under organic amendments, located in the Yaqui Valley, Mexico. Morphological and microscopical characterization showed off-white irregular colonies and Gram-positive bacillus, respectively. The draft genome sequence of this strain revealed a genomic size of 5,489,151 bp, with a G + C content of 35.21%, N50 value of 245,934 bp, L50 value of 8, and 85 contigs. Taxonomic affiliation showed that strain TSO55 belongs to Bacillus paranthracis, reported as an emergent human pathogen. Genome annotation identified 5743 and 5587 coding DNA sequences (CDSs), respectively, highlighting genes associated with indole production, phosphate and potassium solubilization, and iron acquisition. Further in silico analysis indicated the presence of three CDSs related to pathogenicity islands and a high pathogenic potential (77%), as well as the presence of multiple gene clusters related to antibiotic resistance. The in vitro evaluation of plant growth promotion traits was negative for indole production and phosphate and potassium solubilization, and it was positive but low (18%) for siderophore production. The biosynthetic gene cluster for bacillibactin (siderophore) biosynthesis was confirmed. Antifungal bioactivity of strain TSO55 evaluated against wheat pathogenic fungi (Alternaria alternata TF17, Bipolaris sorokiniana TPQ3, and Fusarium incarnatum TF14) showed minimal fungal inhibition. An antibiotic susceptibility assay indicated resistance to three of the six antibiotics evaluated, up to a concentration of 20 µg/mL. The beta hemolysis result on blood agar reinforced TSO55’s pathogenic potential. Inoculation of B. paranthracis TSO55 on wheat seedlings resulted in a significant decrease in root length (−8.4%), total plant height (−4.2%), root dry weight (−18.6%), stem dry weight (−11.1%), and total plant dry weight (−15.2%) compared to the control (uninoculated) treatment. This work highlights the importance of analyzing the microbiological safety of organic amendments before application. Comprehensive genome-based taxonomic affiliation and bioprospecting of microbial species introduced to the soil by organic agricultural practices and any microbial inoculant will prevent the introduction of dangerous species with non-beneficial traits for crops, which affect sustainability and generate potential health risks for plants and humans. Full article

This study aimed to evaluate the impact of a more cost-efficient strigolactone mimic SL-6 on Chlorella sorokiniana NIVA-CHL 176 growth in comparison with the strigolactone analog GR24 and the plant biostimulant functions of microalgal extracts. Three molar SL-6 concentrations were tested: 10⁻⁷ M, 10⁻⁸ M, and 10⁻⁹ M, respectively. Five parameters of microalgal growth were assessed: optical density, turbidity, biomass production, chlorophyll fluorescence, and pigment concentration. Results after 15 days of culturing revealed that the SL-6 treatments significantly enhanced biomass production (13.53% at 10⁻⁹ M), pigment synthesis, and photosystem II activity (14.38% at 10⁻⁹ M). The highest increases in pigments induced by SL-6 were 15.7% for chlorophyll a (at 10⁻⁸ M SL-6), 12.87% for chlorophyll b (at 10⁻⁹ M SL-6), 2.3% for carotenoids (at 10⁻⁸ M SL-6), and 10.78% for total pigments (at 10⁻⁸ M SL-6) per gram biomass compared to the solvent control (DMSO). Higher doses of GR24 and SL-6 (10⁻⁷ M) inhibited microalgal growth, reducing cell density, biomass production, and pigment synthesis. The microalgal extracts acted as plant biostimulants, stimulating root and shoot elongation and proton pump functioning of mung seedlings in the presence and absence of salt stress. The extracts from SL-6 biostimulated C. sorokiniana were more active as plant biostimulants than the extracts from the non-stimulated C. sorokiniana. Full article

Background/Objectives: Mixotrophic cultivation of microalgae using agro-industrial by-products as supplements offers a sustainable strategy to enhance biomass production and bioactive compound synthesis. This study aimed to evaluate the effects of different agro-industrial by-products—orange peel extract, Cladophora glomerata macroalgal hydrolysate, and solid-state fungal fermentation hydrolysate—on the growth and bioactivity of Chlorella sorokiniana. Methods: Microalgae were cultivated under mixotrophic conditions with different agro-industrial by-products as organic carbon sources. Biomass accumulation was monitored through dry weight measurements. Lipid extraction was carried out using dimethyl carbonate. The antimicrobial activity of the extracted compounds was assessed against Escherichia coli, Bacillus megaterium, and Bacillus subtilis by determining the minimal inhibitconcentrations. Results: Orange peel extract supplementation resulted in the highest biomass production. It increased dry weight by 13.86-fold compared to autotrophic conditions. Cladophora glomerata macroalgal hydrolysate followed with a 5.79-fold increase, and solid-state fungal fermentation hydrolysate showed a 4.14-fold increase. The lipophilic fraction extracted from microalgal biomass showed high yields. Orange peel extract supplementation achieved the highest extraction yield (274.36 mg/g DW). Antimicrobial activity varied based on the supplement used: biomass cultivated with orange peel extract exhibited superior activity against E. coli, whereas Cladophora glomerata macroalgal hydrolysate biomass demonstrated potent activity against B. subtilis (MIC: 5.67 g/mL). Conclusions: These findings underscore the potential of agro-industrial by-products for enhancing microalgal biomass and metabolite production. The observed antimicrobial properties highlight the application of microalgal-derived compounds in sustainable bioprocesses, supporting their use in pharmaceutical and biotechnological applications. Full article

A wide range of seed-borne and soil-borne plant pathogens belonging to various fungal and fungal-like species cause pre-emergence seed decay and post-emergence seedling blights of wheat and other small-grain cereal crops. To prevent the death of the seedlings, poor establishment and reduced stand of the crops, extensive crop rotations, planting good-quality seeds and seed treatments with fungicides are used on regular basis. This study is aimed at assessing the efficacy of pre-sowing seed treatments with cold atmospheric plasma for the disinfestation of winter wheat seed from economically important fungal and fungal-like pathogens. Uninoculated or surface-inoculated with Fusarium culmorum, Bipolaris sorokiniana or Pythium ultimum wheat seeds, the cultivar Madara was treated by cold plasma produced either by microwave torch (MW) or underwater diaphragm discharge (UW) with low power at very short treatment times, or remained untreated controls. As per the treatments, the seeds were sown in a ready-to-use growing medium comprising a mixture of light and dark moss peat (w:w) 90–95%, 5–10% perlite and 3–5 kg/m³ CaCO₃, having an electrical conductivity of 40 mS/m, pH (H₂O) of 5.5–6.5 and moisture content of 60–70%, filling in 250 × 250 × 70 mm aluminum flat seed trays (40 grains per tray, four trays per treatment). The plants were cultivated for 45 days in a growth chamber held at (20 ± 2) °C, set to a cycle of 8 h/night and 16 h/day under fluorescent light of 2000–3000 lux intensity. For each replicate, disease incidence (DI) was determined as the total percentage of missing, dead and apparently symptomatic plants. Seed treatment with a microwave plasma torch with a power of 16 W for 40 s significantly (p < 0.001) reduced seedling blights caused by F. culmorum, B. sorokiniana and P. ultimum by 46.8%, 51.0% and 77.3%, respectively, but limited the emergence of wheat seedlings by 15.9% on average. Simultaneously, the effectiveness of underwater discharge seed treatments reached an average of about a 60% reduction of seedling blight caused by F. culmorum and B. sorokiniana and about 37% of the disease caused by P. ultimum. Pre-sowing treatments with a MW plasma torch with an input power of 11 W and treatment time of 60, 90 or 120 s exposure also showed significant (p < 0.001) effects in controlling winter wheat seedling blights caused by the three pathogens. The effectiveness of the treatment increased with increasing the time period of exposure and reached full disease control (>80% reduction) for B. sorokiniana and P. ultimum seedling blights. This study demonstrated that pre-sowing treatment with a microwave plasma torch and underwater diaphragm discharge at a relatively low input power and short exposure time can be used for disinfestation and the effective control of seedling blights in winter wheat caused by seed-borne fungal pathogens, such as Fusarium culmorum and Bipolaris sorokiniana, and fungal-like oomycetes, such as Pythium ultimum. Full article

The virulence gene ToxA has been proposed to be horizontally transferred between three fungal wheat pathogens (Parastagonospora nodorum, Pyrenophora tritici-repentis, and Bipolaris sorokiniana) as part of a conserved ~14 kb ToxhAT transposon. Here, our analysis of 2137 fungal species-representative assemblies revealed that the ToxA gene is an isolate of Alternaria ventricosa and shows a remarkable 99.5% similarity to those found in B. sorokiniana and P. tritici-repentis. Analysis of the regions flanking ToxA within A. ventricosa revealed that it was embedded within a 14 kb genomic element nearly identical to the corresponding ToxhAT regions in B. sorokiniana, P. nodorum, and P. tritici-repentis. Comparative analysis further showed that ToxhAT in A. ventricosa resides within a larger mobile genetic element, which we identified as a member of the Starship transposon superfamily, named Frontier. Our analysis demonstrated that ToxhAT has been independently captured by three distinct Starships—Frontier, Sanctuary, and Horizon—which, despite having minimal sequence similarity outside of ToxhAT, facilitate its mobilization. These findings place Frontier, Sanctuary, and Horizon within a growing class of Starships implicated in the horizontal transfer of adaptive genes among fungal species. Moreover, we identified three distinct HGT events involving ToxA across these four fungal species, reinforcing the hypothesis of a single evolutionary origin for the ToxhAT transposon. These findings underscore the pivotal role of transposon-mediated HGT in the adaptive evolution of eukaryotic pathogens, offering new insights into how transposons facilitate genetic exchange and shape host–pathogen interactions in fungi. Full article

Chlorella species are fast-growing microalgae with significant industrial applications. The aim of the present study was to investigate the antitumor, antioxidant, and hemolytic activities of Chlorella sorokiniana UTEX 1230 crude methanol extracts and fractions. Ch. sorokiniana crude methanol extracts and collective fractions (CFs) were obtained from lyophilized biomass by maceration and column chromatography. Antitumor assays against murine lymphoma L5178Y-R and human breast cancer MCF-7 cells were performed by the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction technique, using human peripheral blood mononuclear cells (PBMC) as the control group. Antioxidant and hemolytic activities were evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH) and erythrocyte hemolysis, respectively. We showed that crude methanol extracts (IC₅₀) increased L5178Y-R and MCF-7 cell growth inhibition, without affecting PBMC. In addition, all evaluated CFs showed significantly higher antioxidant activity than the positive control (ascorbic acid). CF3 and CF4 showed the highest cytotoxicity against L5178Y-R, whereas CF3, CF4, and CF5 caused the highest antitumor activity against MCF-7 cells. CF3, CF4, and CF5 induced significantly higher hemolytic activity compared with all other fractions. CF characterization revealed loliolide, cinnamic acid, methyl dihydrojasmonate, salsalvamide A, 1-monolinolenin, cryptophycin 29, costunolide, riboflavin lumicrome, and germicidin B, which have been related to antitumor and antioxidant activities. In conclusion, we demonstrated that Ch. sorokiniana extracts and fractions possess antitumor and antioxidant potential, without affecting human erythrocytes and PBMC. Full article

It is essential to hunt for new technologies that promote sustainable practices for agroecosystems; thus, the bioprospecting of beneficial microorganisms complementing with mutation induction techniques to improve their genomic, metabolic, and functional traits is a promising strategy for the development of sustainable microbial inoculants. Bacillus cabrialesii subsp. cabrialesii strain TE3^T, a previously recognized plant growth-promoting and biological control agent, was subjected to UV mutation induction to improve these agro-biotechnological traits. Dilutions were made which were spread on Petri dishes and placed under a 20 W UV lamp at 10-min intervals for 60 min. After the UV-induced mutation of this strain, 27 bacterial colonies showed morphological differences compared to the wild-type strain; however, only a strain named TE3^T-UV25 showed an improvement in 53.6% of the biocontrol against Bipolaris sorokiniana vs. the wild-type strain, by competition of nutrient and space (only detected in the mutant strain), as well as diffusible metabolites. Furthermore, the ability to promote wheat growth was evaluated by carrying out experiments under specific greenhouse conditions, considering un-inoculated, strain TE3^T, and strain TE3^T-UV25 treatments. Thus, after 120 days, biometric traits in seedlings were quantified and statistical analyses were performed, which showed that strain TE3^T-UV25 maintained its ability to promote wheat growth in comparison with the wild-type strain. On the other hand, using bioinformatics tools such as ANI, GGDC, and TYGS, the Overall Genome Relatedness Index (OGRI) and phylogenomic relationship of mutant strain TE3^T-UV25 were performed, confirming that it changed its taxonomic affiliation from B. cabrialesii subsp. cabrialesii to Bacillus subtilis. In addition, genome analysis showed that the mutant, wild-type, and B. subtilis strains shared 3654 orthologous genes; however, a higher number of shared genes (3954) was found between the TE3^T-UV25 mutant strain and B. subtilis 168, while the mutant strain shared 3703 genes with the wild-type strain. Genome mining was carried out using the AntiSMASH v7.0 web server and showed that mutant and wild-type strains shared six biosynthetic gene clusters associated with biocontrol but additionally, pulcherriminic acid cluster only was detected in the genome of the mutant strain and Rhizocticin A was exclusively detected in the genome of the wild-type strain. Finally, using the PlaBase tool, differences in the number of genes (17) associated with beneficial functions in agroecosystems were detected in the genome of the mutant vs. wild-type strain, such as biofertilization, bioremediation, colonizing plant system, competitive exclusion, phytohormone, plant immune response stimulation, putative functions, stress control, and biocontrol. Thus, the UV-induced mutation was a successful strategy to improve the bioactivity of B. cabrialesii subsp. cabrialesii TE3^T related to the agro-biotecnology applications. The obtained mutant strain, B. subtilis TE3^T-UV25, is a promising strain to be further studied as an active ingredient for the bioformulation of bacterial inoculants to migrate sustainable agriculture. Full article

The general lack of knowledge on the conditions of Western Siberia (Omsk region) and the taxonomic diversity of zonal soils determines the relevance of these studies. The research was carried out in order to study the effect of complex biologics on the taxonomic diversity of the fungal component of the microbiome of the rhizosphere of cereals and the phytosanitary condition of crops in the southern forest-steppe (meadow-chernozem soil) and subtaiga (gray forest soil) zones of the Omsk Irtysh region (Western Siberia). This work was carried out in 2022–2023, using laboratory studies in combination with field experiments and metagenomic and statistical analyses. The objects of research were varieties of cereals and grain forage crops of Omsk selection: soil microorganisms. The scheme of the experiment involved the study of the following options: varieties of cereals (factor A): spring soft wheat—Omsk 42, Omsk 44, Tarskaya 12; durum wheat—Omsk coral; barley—Omsk 101; oats—Siberian hercules; bacterial preparation for seed inoculation (factor B) without the drug—Mizorin and Flavobacterin. The sampling of the plant rhizosphere for metagenomic analysis was carried out during the earing phase (July). For the first time, the taxonomic composition of the fungal community was determined based on the analysis of amplicon libraries of fragments of ribosomal operons of ITS2 fungi during colonization of crop roots by nitrogen-fixing bacteria in various soil and climatic zones of the Omsk region. The fungal component of the microbiome was analyzed in two zones of the Omsk region (southern forest-steppe and subtaiga). The five dominant phyla of soil fungi were located in the following decreasing series: Ascomycota (about 70%) > Mortierellomycota (about 7%) > Basidiomycota (about 5%) > Mucoromycota (3%) > Chytridiomycota (1%). The five main genera of fungi inhabiting the rhizosphere of cereals are located in a decreasing row: Giberella (6.9%) > Mortierella (6.6%) > Chaetomium (4.8%) > Cladosporium (3.8%) > Rhizopus (3.3%). The predominantly positive effect of biologics of associative nitrogen fixation on the fungal community of the soil (rhizosphere) of experimental sites located in different soil and climatic zones has been established. During seed bacterization, the growth of saprotrophic fungal genera was noted in relation to the control variants Pseudogymnoascus, Chloridium, Clonostachys, Trihoderma, etc., and the fungicidal properties of bacterial strains introduced into the soil were actively manifested relative to phytopathogenic fungi of the genera Alternaria, Blumeria, Fusarium, etc. According to the results of determining the number of infectious structures of Rhizoctonia solani, it was found that the population of the soil with viable cells of this pathogen was 1–3 pcs/g (below the threshold of harmfulness, PV 20 pcs/g of soil), which indicates a favorable phytosanitary situation with respect to the pathogen. The fungicidal effect of the applied bacterial fertilizers on Rhizoctonia solani could not be detected. The number of Bipolaris sorokiniana varied depending on the drug used. In the conditions of the southern forest-steppe zone of the Omsk region (meadow-chernozem soil), the greatest fungicidal effect was noted in Flavobacterin application variants on wheat of the Omsk 42 variety, durum wheat of the Omsk coral variety, and barley; the decrease in conidia relative to the control was 73, 35, and 29%, respectively. In the subtaiga zone of the Omsk Irtysh region (gray forest soil), as in the southern forest-steppe zone, pre-sowing bacterization of seeds with Flavobacterin led to a decrease in Bipolaris sorokiniana in the rhizosphere of wheat of the Omsk 42 variety by 18%, and oats by 27%, to control. The use of the drug Mizorin in some variants of the experiment led to an insignificant decrease in the harmful fungus or had no effect at all. Full article

Bipolaris sorokiniana, a barley pathogen, can infect via seeds, co-growing plants, or soil, causing yield and seed value reductions. This study aimed to assess B. sorokiniana’s impact at various growth stages on seed yield and quality. Results showed no direct impact on yield (which ranged from 0.49 kg·m⁻² for the naked variety Rastik to 0.77 kg·m⁻² for the Widawa variety), but revealed significant seed quality differences. Thousand kernel weight (TKW) and germination capacity (GC) varied notably between examined varieties. The largest kernels were observed for the Bryl variety (27.33 g), which also had the best germination (82.8%). The variety Ryton had the smallest kernels (24.04 g), while the poorest germination (56.7%) was observed for naked kernels of Rastik. A seed health analysis found a relation between inoculation stage and the intensity of spontaneous infection by pathogenic fungi, ranging from 86.4% for the control to more than 95% for the kernels harvested from plants inoculated at the flowering stage. Strong correlation emerged between B. sorokiniana grain infection and germination capacity, highlighting the fungus’s role in seed quality decline. Full article

Rotavirus is the main cause of acute diarrhea in children up to five years of age. In this regard, probiotics are commonly used to treat or prevent gastroenteritis including viral infections. The anti-rotavirus effect of Bifidobacterium longum and Chlorella sorokiniana, by reducing viral infectivity and improving IFN-type I response, has been previously reported. The present study aimed to study the effect of B. longum and/or C. sorokiniana on modulating the antiviral cellular immune response mediated by IFN-γ, IL-10, SOCS3, STAT1, and STAT2 genes in rotavirus-infected cells. To determine the mRNA relative expression of these genes, HT-29 cells were treated with B. longum and C. sorokiniana alone or in combination, followed by rotavirus infection. In addition, infected cells were treated with B. longum and/or C. sorokiniana. Cellular RNA was purified, used for cDNA synthesis, and amplified by qPCR. Our results demonstrated that the combination of B. longum and C. sorokiniana stimulates the antiviral cellular immune response by upregulating IFN-γ and may block pro-inflammatory cytokines by upregulating IL-10 and SOCS3. The results of our study indicated that B. longum, C. sorokiniana, or their combination improve antiviral cellular immune response and might modulate pro-inflammatory responses. Full article

To evaluate the potential of a bacterial strain as a fungal disease control agent and plant growth promoter, its inhibitory effects on phytopathogens such as Bipolaris sorokiniana, Botrytis cinerea, Colletotrichum capsici, Fusarium graminearum, F. oxysporum, Neocosmospora rubicola, Rhizoctonia solani, and Verticillium dahliae were investigated. The results showed that the inhibitory rates in dual-culture and sterile filtrate assays against these eight phytopathogens ranged from 57% to 83% and from 36% to 92%. The strain was identified as Bacillus velezensis based on morphological and physiological characterization as well as phylogenetic analyses of 16S rRNA and the gyrase subunit A protein (gyrA) regions. The results demonstrated that B. velezensis was able to produce fungal cell-wall-degrading enzymes, namely, protease, cellulase, and β-1,3-glucanase, and the growth-promotion substances indole-3-acetic acid (IAA) and siderophore. Furthermore, B. velezensis BV01 had significant control effects on wheat root rot and pepper Fusarium wilt in a greenhouse. Potted growth-promotion experiments displayed that BV01 significantly increased the height, stem diameter, and aboveground fresh and dry weights of wheat and pepper. The results imply that B. velezensis BV01, a broad-spectrum biocontrol bacterium, is worth further investigation regarding its practical applications in agriculture. Full article

In terrestrial plants, strigolactones act as multifunctional endo- and exo-signals. On microalgae, the strigolactones determine akin effects: induce symbiosis formation with fungi and bacteria and enhance photosynthesis efficiency and accumulation of biomass. This work aims to synthesize and identify strigolactone mimics that promote photosynthesis and biomass accumulation in microalgae with biotechnological potential. Novel strigolactone mimics easily accessible in significant amounts were prepared and fully characterized. The first two novel compounds contain 3,5-disubstituted aryloxy moieties connected to the bioactive furan-2-one ring. In the second group of compounds, a benzothiazole ring is connected directly through the cyclic nitrogen atom to the bioactive furan-2-one ring. The novel strigolactone mimics were tested on Chlorella sorokiniana NIVA-CHL 176. All tested strigolactones increased the accumulation of chlorophyll b in microalgae biomass. The SL-F3 mimic, 3-(4-methyl-5-oxo-2,5-dihydrofuran-2-yl)-3H-benzothiazol-2-one (7), proved the most efficient. This compound, applied at a concentration of 10⁻⁷ M, determined a significant biomass accumulation, higher by more than 15% compared to untreated control, and improved the quantum yield efficiency of photosystem II. SL-F2 mimic, 5-(3,5-dibromophenoxy)-3-methyl-5H-furan-2-one (4), applied at a concentration of 10⁻⁹ M, improved protein production and slightly stimulated biomass accumulation. Potential utilization of the new strigolactone mimics as microalgae biostimulants is discussed. Full article