Fungus Fusarium Research Articles

Variations in irradiation energy and rose bengal concentration for photodynamic antimicrobial therapy of fungal keratitis isolates.

The purpose is to assess the efficacy of rose bengal photodynamic antimicrobial therapy (PDAT) using different irradiation energy levels and photosensitizer concentrations for the inhibition of fungal keratitis isolates. Seven different fungi (Aspergillus fumigatus, Candida albicans, Curvularia lunata, Fusarium keratoplasticum, Fusarium solani, Paecilomyces variotii, and Pseudallescheria boydii) were isolated from patients with confirmed infectious keratitis. Experiments were performed in triplicate with suspensions of each fungus exposed to different PDAT parameters including a control, green light exposure of 5.4J/cm2, 2.7J/cm2 (continuous and pulsed), and 1.8J/cm2 and rose bengal concentrations of 0.1%, 0.05%, and 0.01%. Plates were photographed 72h after experimentation, and analysis was performed to assess fungal growth inhibition. PDAT using 5.4J/cm2 of irradiation and 0.1% rose bengal completely inhibited growth of five of the seven fungal species. Candida albicans and Fusarium keratoplasticum were the most susceptible organisms, with growth inhibited with the lowest fluence and minimum rose bengal concentration. Fusarium solani, Pseudallescheria boydii, and Paecilomyces variotii were inhibited by lower light exposures and photosensitizer concentrations. Aspergillus fumigatus and Curvularia lunata were not inhibited by any PDAT parameters tested. Continuous and pulsed irradiation using 2.7J/cm2 produced similar results. Rose bengal PDAT successfully inhibits the in vitro growth of five fungi known to cause infectious keratitis. Differences in growth inhibition of the various fungi to multiple PDAT parameters suggest that susceptibilities to PDAT are unique among fungal species. These findings support modifying PDAT parameters based on the infectious etiology.

Complete genome sequence of a novel mitovirus isolated from the fungus Fusarium oxysporum f. sp. ginseng causing ginseng root rot.

A novel mitovirus, tentatively designated as "Fusarium oxysporum mitovirus 2" (FoMV2), was isolated from the pathogenic Fusarium oxysporum f. sp. ginseng strain 0414 infecting Panax ginseng. The complete genome of FoMV2 is 2388 nt in length with a GC content of 30.57%. It contains a large open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) of 713 amino acids with a molecular weight of 83.05 kDa. The sequence identity between FoMV2 and Botrytis cinerea mitovirus 8 and Fusarium verticillioides mitovirus 1 was 87.94% and 77.85%, respectively. Phylogenetic analysis showed that FoMV2 belongs to the genus Unuamitovirus in the family Mitoviridae. To the best of our knowledge, this is the first report of an unuamitovirus isolated from F. oxysporum f. sp. ginseng causing ginseng root rot.

A novel core-shell up-conversion nanoparticles immunochromatographic assay for the detection of deoxynivalenol in cereals

Deoxynivalenol (DON) toxin is a type B group of trichothecene mycotoxins mainly originating from specific Fusarium fungi, seriously harming human and livestock health. Herein, a novel core-shell up-conversion nanoparticles immunochromatographic assay (CS-UCNPs-ICA) was developed for deoxynivalenol based on the competitive reaction principle. By exploiting the fluorescence intensity of the T and C lines of CS-UCNPs-ICA, the concentrations of DON were obtained sensitively and precisely under optimized conditions in 5 min with a detection limit of 0.1 ng/mL. The CS-UCNPs-ICA strips only specifically detect DON and its derivatives (3-Ac-DON and 15-Ac-DON), with no cross-reaction with other mycotoxins. The low CV values illustrated a modest intra- and inter-assay variation, confirming the superior precision of this method. In the spiked experiment, the mean recoveries of corn and wheat ranged from 94.74% to 100.90% and 96.21%–104.81%, respectively. Furthermore, the approach generated results that were in good agreement with data from HPLC and ELISA analyses of naturally contaminated feed and cereals, confirming that the significant advantages of proposed strips were their high practicality, rapidness, and simplicity. Therefore, the CS-UCNPs-ICA strips platform serves as a promising candidate for developing new approaches for rapid testing or high throughput screening from DON in food products.

A novel alternavirus with three dsRNA segments from Fusarium pseudograminearum, the pathogen of Fusarium crown rot in wheat.

Three dsRNA segments were detected in Fusarium pseudograminearum strain CF14029, a pathogen causing Fusarium crown rot in China. Characterization and sequence analysis confirmed that these dsRNA sequences originated from the same virus. The viral genome consists of three dsRNA segments: dsRNA1 (3,560 nt in length), encoding an RNA-dependent RNA polymerase (RdRp), dsRNA2 (2,544 nt in length), encoding a hypothetical protein, and dsRNA3 (2,478 nt in length), encoding a putative coat protein (CP). Phylogenetic analysis based on the RdRp and CP amino acid sequences revealed a high degree of similarity of this virus to members of the genus Alternavirus, family Alternaviridae, isolated from other Fusarium fungi. As a novel member of the genus Alternavirus, this virus was provisionally named "Fusarium pseudograminearum alternavirus 1" (FpgAV1). Like other alternaviruses found in Fusarium species, the positive-sense strand of each genomic dsRNA of FpgAV1 possesses a poly(A) tail and a distinctive 5'-terminal octamer sequence (5'-GCT GTG TG-3'). This is the first report of the genomic sequence of an alternavirus identified in F. pseudograminearum.

Variations in rhizosphere soil dominant and pathogenic flora improve boron-efficient Beta vulgaris L. yield under boron deficit

Boron (B)-efficient sugarbeet can potentially adapt better to the B deficient soil environments, however the characteristics of root yield or quality and rhizosphere soil microbial dynamics associated with B-efficient beet roots are extremely understudied. This study aimed to clarify the root yield characteristics and rhizosphere microbial response of B-efficient sugarbeet variety under B deficiency. Pertinently, the findings of this study will contribute to the reduction of B resource consumption and cleaner production in sugarbeet planting management. The study utilized two sugarbeet varieties with different B utilization propensities and subjected them to normal and B deficient field conditions. Results demonstrated a reduction in the yield quality of both varieties under B deficiency, but the B-efficient variety exhibited a smaller reduction. Boron deficiency reduced the species richness and diversity of the rhizospheric microbial community, decreasing the relative abundance of Actinobacteriota, Acidobacteria, while increasing that of Proteobacteria, Chloroflexi and the pathogenic fungus Fusarium. The proportion of dominant bacterial was severely reduced in B-inefficient varieties (0.86%) compared to B-efficient varieties (0.14%). The efficient variety displayed higher species richness of rhizospheric soil fungi and a higher abundance and proportion of dominant flora, i.e., Bacillus and Actinobacteria, albeit lower abundance of the pathogenic fungi Mortierellomycota and Rhizoctonia. These advantages allowed B-efficient sugarbeet variety to maintain higher yield levels under B deficit. Overall, under B-deficient conditions, B-efficient variety of sugarbeet was less limited than B-inefficient one, and its rhizosphere microbial communities were more conducive to sugarbeet yield in terms of composition and function. Succinctly, this study revealed the advantages of rhizosphere soil microorganisms associated with B-efficient beet under B-deficient environments and provided the theoretical basis for reducing boron fertilizer application to protect the ecosystem and realize green and clean agricultural production, particularly of sugar beet.

Biological activities and GC-MS analysis of crude extract of an endophytic fungus Fusarium sp. F1C1

Biological activities and GC-MS analysis of crude extract of an endophytic fungus Fusarium sp. F1C1

Profiling of deubiquitinases that control virulence in the pathogenic plant fungus Fusarium graminearum.

Eukaryotes have evolved sophisticated post-translational modifications to regulate protein function and numerous biological processes, including ubiquitination controlled by the coordinated action of ubiquitin-conjugating enzymes and deubiquitinating enzymes (Dubs). However, the function of deubiquitination in pathogenic fungi is largely unknown. Here, the distribution of Dubs in the fungal kingdom was surveyed and their functions were systematically characterized using the phytopathogen Fusarium graminearum as the model species, which causes devastating diseases of all cereal species world-wide. Our findings demonstrate that Dubs are critical for fungal development and virulence, especially the ubiquitin-specific protease 15 (Ubp15). Global ubiquitome analysis and subsequent experiments identified three important substrates of Ubp15, including the autophagy-related protein Atg8, the mitogen-activated protein kinase Gpmk1, and the mycotoxin deoxynivalenol (DON) biosynthetic protein Tri4. Ubp15 regulates the deubiquitination of the Atg8, thereby impacting its subcellular localization and the autophagy process. Moreover, Ubp15 also modulates the deubiquitination of Gpmk1 and Tri4. This modulation subsequently influences their protein stabilities and further affects the formation of penetration structures and the biosynthetic process of DON, respectively. Collectively, our findings reveal a previously unknown regulatory pathway of a deubiquitinating enzyme for fungal virulence and highlight the potential of Ubp15 as a target for combating fungal diseases.

Fusarium Species Causing Pepper Wilt in Russia: Molecular Identification and Pathogenicity.

Fusarium wilt pathogens represent an ongoing threat to pepper production worldwide. This is the first report providing data on the molecular identification of Fusarium fungi that cause wilt in pepper in the southern regions of Russia. Monitoring of the Fusarium infection on pepper was carried out in 2019-2022 in two economically important regions of this culture production: the Krasnodar Krai and Crimea. Based on a phylogenetic analysis of the translation elongation factor (EF1a) and the internal transcribed spacer (ITS), as well as the macro- and micromorphological characteristics of the fungi, the causative agents of Fusarium wilt have been identified. The causative agents identified as representatives of the Fusarium species composition included: F. clavus, F. solani, F. oxysporum, F. verticillioides, F. commune, F. torulosum, and F. sporotrichioides. Depending on the region, the specifics of biodiversity and the ratio of these species in pathocomplexes were noted. In Crimea, wilting could be attributed to all of the identified species; in the Krasnodar Krai, F. verticillioides and F. clavus were found to contribute to wilting. The pathogenicity test showed that the pathogens of pepper wilting in Russia, in addition to the already known F. oxysporum and F. solani, are the species F. clavus and F. verticillioides. This is the first report on the ability of these species to cause Fusarium wilt in pepper cultures. The obtained data will be of practical value for the development of biological control measures for fungi of the genus Fusarium, which cause pepper wilt in areas of industrial production and seed production. In addition, data on species composition and aggressive isolates will be used in a pepper breeding program for resistance to Fusarium wilt.

Anticancer activity of secondary metabolite isolated from the rhizospheric fungus Fusarium oxysporum isolate-ABRF1, 2-propenoic acid, pentadecyl ester

Abstract. Sahu MK, Suthakaran S, Ghosh SC, Singh D, Das A, Jha H. 2023. Anticancer activity of secondary metabolite isolated from the rhizospheric fungus Fusarium oxysporum isolate-ABRF1, 2-propenoic acid, pentadecyl ester. Asian J Nat Prod Biochem 21: 88-100. The rhizospheric fungus Fusarium oxysporum ABRF1 from the Achanakmar Biosphere Reserve, Chhattisgarh, India, was evaluated for its anticancer potency using various cellular and molecular assays. A differential cytotoxic profile of the different fractions of the ABRF1 isolate was observed against various cancer cell lines. DNA fragmentation analysis revealed the aqueous and toluene fractions were effective and correlated well with apoptotic gene expression in several breast cancer cells. The fractions showed markedly increased expression of pro-apoptotic protein markers – BAX and cleaved caspase 3 in the breast cancer cells. Structural and functional characterization of potential secondary metabolite from the fungal isolate ABRF1 was carried out using Gas Chromatography with Mass Spectroscopy and Nuclear Magnetic Resonance that characterized as 2-propenoic acid, pentadecyl ester. The underlying mechanisms responsible for the anticancer property were confirmed by molecular docking analysis of 2-propenoic acid, pentadecyl ester, and positive controls such as Doxorubicin and Noscapine. The results showed an efficient binding with molecular targets such as protein kinases (EphA2) and epithelial-to-mesenchymal transition markers (Vimentin) in breast cancer cells. The active metabolite 2-propenoic acid, pentadecyl ester, has a potential anticancer property that needs to be taken further for in vivo studies and drug development in the future.

Trichothecenes and Fumonisins: Key Players in Fusarium-Cereal Ecosystem Interactions.

Fusarium fungi produce a diverse array of mycotoxic metabolites during the pathogenesis of cereals. Some, such as the trichothecenes and fumonisins, are phytotoxic, acting as non-proteinaceous effectors that facilitate disease development in cereals. Over the last few decades, we have gained some depth of understanding as to how trichothecenes and fumonisins interact with plant cells and how plants deploy mycotoxin detoxification and resistance strategies to defend themselves against the producer fungi. The cereal-mycotoxin interaction is part of a co-evolutionary dance between Fusarium and cereals, as evidenced by a trichothecene-responsive, taxonomically restricted, cereal gene competing with a fungal effector protein and enhancing tolerance to the trichothecene and resistance to DON-producing F. graminearum. But the binary fungal-plant interaction is part of a bigger ecosystem wherein other microbes and insects have been shown to interact with fungal mycotoxins, directly or indirectly through host plants. We are only beginning to unravel the extent to which trichothecenes, fumonisins and other mycotoxins play a role in fungal-ecosystem interactions. We now have tools to determine how, when and where mycotoxins impact and are impacted by the microbiome and microfauna. As more mycotoxins are described, research into their individual and synergistic toxicity and their interactions with the crop ecosystem will give insights into how we can holistically breed for and cultivate healthy crops.

In Vitro and In Silico Analysis of the Antifungal Activity of Beta-cyclodextrin and Cinnamon Oil Inclusion Complexes against Fusarium oxysporum f. sp. cubense-TR4

The Panama Disease-TR4 is a fatal disease of banana plants caused by the fungus Fusarium oxysporum f. sp. cubense-TR4 (Foc-TR4). Cinnamon oil has known antifungal properties, while beta-cyclodextrin has been proven to protect essential oils from degradation through encapsulation. The study aims to determine the effectiveness of cinnamon oil, and its beta-cyclodextrin complex against Foc-TR4, through their characterization, in vitro antifungal screening, and in silico docking analysis. The characterization of the complex yielded an encapsulation efficiency of 61.18%, an average particle size of 98.27 μm, while its calorimetry confirmed complex formation. Cinnamon oil, beta-cyclodextrin, and the complex were tested against Foc-TR4 through spread plate method against Ivagard (dialkyl dimethyl ammonium chloride) in triplicate. Among the treatments, the complex exhibited significantly weaker antifungal activity, with only cinnamon oil comparable with Ivagard at α = 0.05. Cinnamaldehyde displayed favorable binding energies of -6.1 and -4.9 kcal/mol against the Foc-TR4 proteins, and -3.7 kcal/mol against beta-cyclodextrin. This implies that cinnamaldehyde can spontaneously form stable complexes with the Foc-TR4 proteins or beta-cyclodextrin. These findings suggest the potential of cinnamaldehyde, in cinnamon oil and even in the inclusion complexes, as a viable antifungal treatment against Foc-TR4.

Invasion of an Afrotemperate forest complex by the polyphagous shot hole borer beetle

AbstractThe polyphagous shot hole borer (PSHB), Euwallacea fornicatus Eichhoff (Coleoptera: Curculionidae, Scolytinae), is a significant tree‐killing pest recently introduced into South Africa. Many native trees in urban settings are susceptible to infestation, but the presence of PSHB in natural ecosystems is unstudied. The presence and drivers of PSHB colonization in 1682 trees of 68 species were evaluated in 51 plots across a native Afrotemperate forest complex in South Africa. Breeding colonies of PSHB were found in six native species (breeding hosts). An additional 11 species did not contain PSHB colonies but hosted its mutualistic fungus Fusarium euwallaceae Freeman et al. (Hypocreales: Nectriaceae). Invasibility increased when plots were closer to the urban infestation border, further away from surface water, and when containing a larger number of breeding hosts. Invasibility decreased with an increase in tree species richness. Polyphagous shot hole borers were found in climax forest distant to urban areas at sites frequented by tourists. The severity of infestation of trees increased with an increase in host diameter, breeding host abundance, and infested tree abundance. Probability of infestation increased with an increase in the number of infested trees. Infested trees were not spatially clumped. Instead, PSHB preferentially selected eight of the 17 native host species. And the data suggest that larger trees of these species may be more susceptible to PSHB. Eight species were infested at random and two were infested seemingly accidentally. Infestations increased more rapidly on larger trees and on those surrounded by a high abundance of breeding hosts. This study confirms that Afrotemperate forests are highly susceptible to invasion by PSHB. Direct anthropogenic impact had no discernible effect on infestations, but humans aided spread of PSHB to distant sites. Halting movement of contaminated wood is important. Management of PSHB should focus on highly infested areas and trees as these increase the likelihood of further and more severe infestations.

ANTAGONISTIC ACTIVITY OF ENDOPHYTIC FUNGI ISOLATED FROM ALOE VERA LEAVES AGAINST SOME PLANT PATHOGENIC FUNGI

The present study was aimed to test the antagonistic activity of endophytic fungi isolated from Aloe vera leaves against a number of plant-pathogenic fungi. The results showed that the highest antagonistic activity was exerted by Penicillium chermesinum against the pathogenic fungus Rhizoctonia solani, with an inhibition rate of 78.57%. Also, Talaromyces verruculosus and P. chermesinum showed their highest antagonistic activities against pathogenic fungus Fusarium 1 with inhibition rates of 61.79% and 61.53%, respectively, while T. verruculosus showed an inhibition rate of 62.91% against the pathogenic fungus Fusarium 2. Most of the endophytic fungi showed the least percentage of inhibition against Macrophomina phaseolina compared to the rest of the pathogenic fungi. The fungal filtrates showed a concentration-dependent inhibition rate against the plant pathogens, with a range of 0.00-48.13%. The highest inhibitory activity of Aspergillus niger was recorded at a concentration of 60% against Fusarium 2, R. solani, and Fusarium 1, with rates of 48.13, 37.39, and 36.66%, respectively. The results also showed the ineffectiveness of all fungal filtrates against the pathogenic fungus M. phaseolina. Chemical analysis of the filtrates of the endophytic fungi which showed antagonistic activity against pathogenic fungi was also conducted by using GC-MS. The results showed the presence of effective compounds with biological effects, such as Pentadecanoic acid, Oleic Acid, Limonene, cis-Vaccenic acid, Hexanedioic acid, bis(2-ethylhexyl) ester, Cycloheptasiloxane, and tetracamethyl-.

Transcriptomic and Metabolomic Analyses Reveal the Role of Phenylalanine Metabolism in the Maize Response to Stalk Rot Caused by Fusarium proliferatum.

Stalk rot is a prevalent disease of maize (Zea mays L.) that severely affects maize yield and quality worldwide. The ascomycete fungus Fusarium spp. is the most common pathogen of maize stalk rot. At present, the molecular mechanism of Fusarium proliferation during the maize stalk infection that causes maize stalk rot has rarely been reported. In this study, we investigated the response of maize to F. proliferatum infestation by analyzing the phenotypic, transcriptomic, and metabolomic data of inbred lines ZC17 (resistant) and CH72 (susceptible) with different levels of resistance to stalk rot. Physiological and phenotypic results showed that the infection CH72 was significantly more severe than ZC17 after inoculation. Transcriptome analysis showed that after inoculation, the number of differentially expressed genes (DEGs) was higher in CH72 than in ZC17. Nearly half of these DEGs showed the same expression trend in the two inbred lines. Functional annotation and enrichment analyses indicated that the major pathways enriched for DEGs and DEMs included the biosynthesis of plant secondary metabolites, phenylalanine metabolism, biosynthesis of plant hormones, and plant-pathogen interactions. The comprehensive analysis of transcriptome and metabolome data indicated that phenylalanine metabolism and the phenylalanine, tyrosine, and tryptophan biosynthesis pathways played a crucial role in maize resistance to F. proliferatum infection. In addition, a transcription factor (TF) analysis of the DEGs showed that several TF families, including MYB, bHLH, NAC, and WRKY, were significantly activated after inoculation, suggesting that these TFs play important roles in the molecular regulatory network of maize disease resistance. The findings of this study provide valuable insights into the molecular basis of the response of maize to Fusarium proliferatum infection and highlight the importance of combining multiple approaches, such as phenotyping, transcriptomics, and metabolomics, to gain a comprehensive understanding of plant-pathogen interactions.

Identification of haplotypes associated with resistance to Fusarium graminearum in spring oat (Avena sativa L.)

AbstractFusarium head blight (FHB) is the predominant disease in oat in Norway caused by the fungus Fusarium graminearum. It causes yield loss, reduced seed quality, reduced germination ability and accumulation of deoxynivalenol (DON). The FHB resistance is quantitative, and most genes have small effect. Markers with verified effect in the breeding program could further enhance the resistance breeding. This study aims to use a large and diverse population of 541 lines to identify quantitative trait loci (QTL) associated to FHB resistance in a genome‐wide association study (GWAS) and verify their effect in independent breeding material. The material has been tested in six environments over three years and two locations in spawn inoculated and mist irrigated disease trials. The traits tested were germination ability and DON accumulation. A total of 15 significant QTL‐regions were detected across 12 different linkage groups. Haplotypes for each region was constructed and the effect of the alleles in each environment was calculated, which identified the most likely resistant and susceptible alleles. Five QTL‐regions were validated showing consistent effect in the GWAS population and the breeding material. Stacking of the resistant alleles of these regions from zero to five showed significant decrease in DON values and increased germination ability. The haplotype information of a set of historical and modern Nordic varieties were analysed, and the results could be used to select parents for future crossings. The validated haplotypes from this study can be used either to do marker assisted selection (MAS) or improve genomic prediction models in breeding programs.

Using NGS Technology and Association Mapping to Identify Candidate Genes Associated with Fusarium Stalk Rot Resistance.

Stalk rot caused by Fusarium fungi is one of the most widespread and devastating diseases of maize, and the introduction of resistant genotypes is one of the most effective strategies for controlling the disease. Breeding genotypes with genetically determined resistance will also allow less use of crop protection products. The aim of the research was to identify molecular markers and associated candidate genes determining maize plant resistance to Fusarium stalk rot. The plant material for this study consisted of 122 maize hybrids. The experiment was conducted in two localities: Smolice and Kobierzyce. The Fusarium stalk rot values ranged from 1.65% (for genotype G01.10) to 31.18% (for genotype G03.07) in Kobierzyce and from 0.00% (for 58 genotypes) to 6.36% (G05.03) in Smolice. The analyzed genotypes were simultaneously subjected to next-generation sequencing using the Illumina platform. Illumina sequencing identified 60,436 SilicoDArT markers and 32,178 SNP markers (92,614 in total). For association mapping, 32,900 markers (26,234 SilicoDArT and 6666 SNP) meeting the criteria (MAF > 0.25 and the number of missing observations <10%) were used. The results of the observation of the degree of infection and sequencing were used for association mapping, which ultimately resulted in the selection of ten molecular markers important at both places. Among the identified markers, two SNP markers that are located inside candidate genes play an important role. Marker 4772836 is located inside the serine/threonine-protein kinase bsk3 gene, while marker 4765764 is located inside the histidine kinase 1 gene. Both genes can be associated with plant resistance to Fusarium stalk rot, and these genes can also be used in breeding programs to select resistant varieties.

Athogenic properties of pathogens and the damage of straw- berry varieties by mycoses of the root system

Fungal isolates isolated from garden strawberry plants Fusarium semitectum Berk. Et Ravenel and Verticillium albo-atrum Reinke et Berth proved to be pathogenic. Under field conditions, artificial inoculation with these isolates increased the development of verticillium disease to 24.0-57.0 % and the development of fusarium disease to 26.0-31.0 %, which significantly exceeded the growth of root rot in control at the level of 2.0-2.2 %. Inhibition of the above-ground system length in infected plants reached 6.5-30.5 % relative to the control. In a laboratory experiment, the presence of pathogenic properties in an isolate of the fungus Fusarium solani (Mart.) Sacc., also isolated from strawberry plants, was proved. Artificial inoculation caused a decrease in the length of the above-ground system by 33.2 %, the number of new leaves by 53.8%, a reduction in the size of the roots by 43.9 %, and increased rhizome necrosis by 3.2 times relative to the control. The general condition of strawberry plants in the control was satisfactory by 3.2 points. The negative effect of the phytopathogen in variants with inoculation was manifested in a decrease in the state of plants to a level of 1.3-1.4 points. According to the results of a 3-year observation, the varieties Alexandrina, Festivalnaya Romashka, and Solnechnaya Polyanka showed relative resistance to fusarium disease of strawberries (the development of the disease on average over three years ranged from 2.8 to 5.7 %, with 11.3 % in the standard variety Yunia Smaids). Varieties Feya, hybrid Lutova, Aleksandrina, Festivalnaya Romashka, Solnechnaya Polyanka, Festivalnaya, and Anastasia had relative resistance to verticillium disease (the development of the disease on average over three years ranged from 0 to 1.8 %, with 8.9 % for the standard).

Control of phytopathogen organisms using bioactive compounds contained in orange wax

AbstractOrange wax (OW) is a waxy waste generated in the essential oil purification process (winterization). It has no commercial value. It is discarded or burnt, polluting the environment. The present study demonstrates the possibility of applying it to control phytopathogens. The ethanol‐soluble bioactive compounds of OW were identified and quantified. The effect of orange wax extracts on the growth inhibition of phytopathogenic fungi (Fusarium oxysporum and Colletotrichum gloeosporioides) and Spodoptera frugiperda larvae was evaluated. High‐performance liquid chromatography–mass spectrometry (HPLC‐MS) and gas chromatography–mass spectrometry (GC–MS) quantified 22 bioactive compounds representing 23% (w/w) of OW. Terpineol, limonene, and eremophilene were the most abundant bioactive substances in this material. The distortion of the radial growth of the fungal hyphae was measured in a potato dextrose agar (PDA), and all tested concentrations (6.3, 12.5, 25, 50, and 100 mg/mL) inhibited the radial expansion of C. gloeosporioides. In contrast, only the OW extracts at 50 and 100 mg mL−1 inhibited F. oxysporum. Spray treatments were performed using a Potter spray tower on third‐instar Spodoptera frugiperda larvae. Spraying OW extract at 50 mg mL−1 for 10 s caused the highest larval mortality. However, third‐instar larvae were attracted to consume corn leaves moistened with extract at lower concentrations. Up to 93% of the first‐instar larvae died after eating corn leaves moistened with the extract at 50 mg mL−1. As far as the authors are aware, this is the first scientific report about the use of bioactive compounds of orange wax to control fungi. Spodoptera frugiperda could form the basis for the manufacture of new biopesticides.

The fatty acid 2-hydroxylase CsSCS7 is a key hyphal growth factor and potential control target in Colletotrichum siamense.

SCS7 is a fatty acid 2-hydroxylase required for the synthesis of inositol phosphorylceramide but is not essential for normal growth in Saccharomyces cerevisiae. Here, we demonstrate that the Colletotrichum siamense SCS7 homolog CsSCS7 plays a key role in hyphal growth. The CsSCS7 deletion mutant showed strong hyphal growth inhibition, small conidia, and marginally reduced sporulation and also resulted in a sharp reduction in the full virulence and increasing the fungicide sensitivity. The three protein domains (a cytochrome b5 domain, a transmembrane domain, and a hydroxylase domain) are important to CsSCS7 protein function in hyphal growth. The fatty acid assay results revealed that the CsSCS7 gene is important for balancing the contents of multiple mid-long- and short-chain fatty acids. Additionally, the retarded growth and virulence of C. siamense ΔCsSCS7 can be recovered partly by the reintroduction of homologous sequences from Magnaporthe oryzae and Fusarium graminearum but not SCS7 of S. cerevisiae. In addition, the spraying of C. siamense with naked CsSCS7-double-stranded RNA (dsRNAs), which leads to RNAi, increases the inhibition of hyphal growth and slightly decreases disease lesions. Then, we used nano material Mg-Al-layered double hydroxide as carriers to deliver dsRNA, which significantly enhanced the control effect of dsRNA, and the lesion area was obviously reduced. These data indicated that CsSCS7 is an important factor for hyphal growth and affects virulence and may be a potential control target in C. siamense and even in filamentous plant pathogenic fungi.IMPORTANCECsSCS7, which is homologous to yeast fatty acid 2-hydroxylase SCS7, was confirmed to play a key role in the hyphal growth of Colletotrichum siamense and affect its virulence. The CsSCS7 gene is involved in the synthesis and metabolism of fatty acids. Homologs from the filamentous fungi Magnaporthe oryzae and Fusarium graminearum can recover the retarded growth and virulence of C. siamense ΔCsSCS7. The spraying of double-stranded RNAs targeting CsSCS7 can inhibit hyphal growth and reduce the disease lesion area to some extent. After using nano material Mg-Al layered double hydroxide as carrier, the inhibition rates were significantly increased. We demonstrated that CsSCS7 is an important factor for hyphal growth and affects virulence and may be a potential control target in C. siamense and even in filamentous plant pathogenic fungi.

Chemical Composition, Antioxidant Activity, and Control Potential of Botanical Fermented Products on Phytopathogenic Fungi of Agricultural Interest

Purpose: This work aimed to evaluate the chemical composition and bioactivity of fermented extracts of the botanical species Platycladus orientalis, Cupressus sempervirens, Ricinus communis, Artemisia absinthium, and Picrasma crenata, assessed at 10 %, 20 %, and 40 % v/v on the mycelial development of phytopathogenic fungi Colletotrichum fructicola, Sclerotium rolfsii, and Fusarium oxysporum. Theoretical framework: The search for sustainable alternatives that are less harmful to the environment regarding synthetic agrochemicals has intensified in recent years. Among the different approaches to mitigate this problem, the use of molecules of biological origin and biotransformed botanical extracts is an important research topic in the area. However, the potential for using fermented botanical extracts is still little explored, and it is necessary to study these materials to evaluate their actual biological activity systematically and, consequently, the potential for practical use, especially in areas such as agriculture. Methods: The antioxidant activity before and after the fermentation process, as well as the levels of phenolic compounds, flavonoids, and individual phenolics, were determined by spectrophotometry and high-performance liquid chromatography. The mycelial growth of Colletotrichum fructicola was evaluated in vitro in a PDA medium containing the fermented ones at zero, 10 %, 20 %, and 40 % v/v. Results and conclusion: The main phenolic compound identified was gallic acid in fermented A. absinthium, followed by P. crenata and R. communis. These same species showed inhibitory activity between 44.0 % and 34.6 %, at a concentration of 40 % v/v, on the mycelial development of C. fructicola. As for the antioxidant activity of the analyzed fermented products and the evaluation of phenolic compounds before and after the fermentation of plant extracts, the results before varied between 58 – 79 %, and in the post-fermentation, the activity was maintained only for the fermented products of C. sempervirens and P. orientalis, a fact also verified in the same species relative to the levels of phenolic compounds. No inhibitory effect was observed on the fungi, showing that these fermentates are ineffective as antifungal agents. Research implications: This work showed that these botanical fermented products do not have any antifungal effect on these phytopathogens. So, further research is necessary to improve their antifungal effect. Originality/value: Few studies address the biological activity of fermented extracts and their potential for agricultural application. In this sense, the present study aims to verify the antifungal activity of different botanical fermentates to evaluate their potential use as an alternative to synthetic products.