Fungus Colletotrichum Research Articles

Broad-spectrum fungal resistance in sorghum is conferred through the complex regulation of an immune receptor gene embedded in a natural antisense transcript.

Sorghum (Sorghum bicolor), the fifth most widely grown cereal crop globally, provides food security for millions of people. Anthracnose caused by the fungus Colletotrichum sublineola is a major disease of sorghum worldwide. We discovered a major fungal resistance locus in sorghum composed of the nucleotide-binding leucine-rich repeat receptor gene ANTHRACNOSE RESISTANCE GENE1 (ARG1) that is completely nested in an intron of a cis-natural antisense transcript (NAT) gene designated CARRIER OF ARG1 (CARG). Susceptible genotypes express CARG and two alternatively spliced ARG1 transcripts encoding truncated proteins lacking the leucine-rich repeat domains. In resistant genotypes, elevated expression of an intact allele of ARG1, attributed to the loss of CARG transcription and the presence of miniature inverted-repeat transposable element sequences, resulted in broad-spectrum resistance to fungal pathogens with distinct virulence strategies. Increased ARG1 expression in resistant genotypes is also associated with higher histone H3K4 and H3K36 methylation. In susceptible genotypes, lower ARG1 expression is associated with reduced H3K4 and H3K36 methylation and increased expression of NATs of CARG. The repressive chromatin state associated with H3K9me2 is low in CARG-expressing genotypes within the CARG exon and higher in genotypes with low CARG expression. Thus, ARG1 is regulated by multiple mechanisms and confers broad-spectrum, strong resistance to fungal pathogens.

Preinvasive nonhost resistance of Arabidopsis against melanized appressorium-mediated entry of multiple nonadapted Colletotrichum fungi

ABSTRACT Nonhost plants effectively block a vast number of nonadapted fungal pathogens at the preinvasive stage. On the host plants, adapted fungal pathogens such as Colletotrichum species invade into plant epidermal cell by penetration peg developed from melanized appressorium, followed by invasive hyphal extension. I reported nonadapted Colletotrichum fungi that showed an increased rate of melanized appressorium-mediated entry (MAE) into the pen2 mutant of nonhost Arabidopsis thaliana (hereafter Arabidopsis). It was also found that other MAE-type nonadapted Colletotrichum fungi with no penetration into the pen2 mutant invaded Arabidopsis in the presence of additional mutations such as edr1, gsh1, eds5, cas, and chup1 in the pen2 background. Thus, many immune components contribute to the preinvasive nonhost resistance (NHR) of Arabidopsis against Colletotrichum MAE, and PEN2-related defense takes priority over other defense pathways. Here, I show that among the above nonadapted fungi, Colletotrichum nymphaeae PL1-1-b exhibited relatively lower incompatibility with the nonhost Arabidopsis with increased MAE in each single mutant of edr1, gsh1, eds5, and cas, although other nonadapted fungi almost never invaded these single mutants. Based on the relationships between Colletotrichum MAE and the Arabidopsis immune-related components, Colletotrichum-Arabidopsis incompatibility and multilayered immunity in the preinvasive NHR of Arabidopsis are discussed in this study.

Transcriptome Analysis Reveals the Inducing Effect of Bacillus siamensis on Disease Resistance in Postharvest Mango Fruit.

Postharvest anthracnose, caused by the fungus Colletotrichum gloeosporioides, is one of the most important postharvest diseases of mangoes worldwide. Bacillus siamensis (B. siamensis), as a biocontrol bacteria, has significant effects on inhibiting disease and improving the quality of fruits and vegetables. In this study, pre-storage application of B. siamensis significantly induced disease resistance and decreased disease index (DI) of stored mango fruit. To investigate the induction mechanisms of B. siamensis, comparative transcriptome analysis of mango fruit samples during the storage were established. In total, 234,808 unique transcripts were assembled and 56,704 differentially expressed genes (DEGs) were identified by comparative transcriptome analysis. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEGs showed that most of the DEGs involved in plant-pathogen interaction, plant hormone signal transduction, and biosynthesis of resistant substances were enriched. Fourteen DEGs related to disease-resistance were validated by qRT-PCR, which well corresponded to the FPKM value obtained from the transcriptome data. These results indicate that B. siamensis treatment may act to induce disease resistance of mango fruit by affecting multiple pathways. These findings not only reveal the transcriptional regulatory mechanisms that govern postharvest disease, but also develop a biological strategy to maintain quality of post-harvest mango fruit.

Augmented Growth of Cd-Stressed Rice Seedlings with the Application of Phytostimulating, Root-Colonizing, Cd-Tolerant, Leaf-Endophytic Fungi Colletotrichum Spp. Isolated from Eupatorium Triplinerve

Augmented Growth of Cd-Stressed Rice Seedlings with the Application of Phytostimulating, Root-Colonizing, Cd-Tolerant, Leaf-Endophytic Fungi Colletotrichum Spp. Isolated from Eupatorium Triplinerve

Classification of Microscopic Images of Fungi Using Deep Learning Models

The paper aims to identify the microscopic images of fungi Colletotrichum gloeosporioides and Cylindrocladium colhounii, which affect the leaves of Mango and Custard apple plant. The affected leaves are collected, cultivated and observed under high power 40X objective lens. The collected dataset is brand new of 78 images and feed to the two pre-trained deep learning models AlexNet and SqueezeNet. We propose an idea of identifying these fungi at microscopic level, where not much of work is done on fruit plants of Hyderabad and Karnataka (H8K) region of Karnataka, India. Using the CNN models, performance measures such as mean precision, mean recall, F1 score and accuracy are calculated and it is observed that AlexNet model gives a good recognition accuracy of 93.8% compared to the SqueezeNet model.

Effect of several types of endophytic fungi isolates Beauveria bassiana in suppressing seed-borne pathogens Colletotrichumspp

Anthracnose is one of the most important seed-borne diseases in chili plants because this disease can reduce the quantity and quality of chilies and cause substantial economic losses. The aim of this study was to obtain the best isolates from various types of endophytic fungi Beauveria bassiana in suppressing the growth of pathogens. chili seed borne disease caused by the fungus Colletotrichum spp. The design used in this study was a completely randomized design (CRD) consisting of 6 treatments. The treatments consisted of control and 5 types of B. bassiana isolates (PD114, TD312, WS, BbKo, KT2B23). Parameters observed in this study were chili seeds that were attacked by Colletotrichum spp., normal seed germination on paper-to-paper test, length of plumule and radicle. Results. The study showed that different types of B. bassiana isolates could reduce the attack rate of seed-borne pathogenic fungi Colletotrichum spp. KT2B23 isolate was the best isolate in suppressing chili seed-borne pathogens.

Genome-Wide Identification of Key Components of RNA Silencing in Two Phaseolus vulgaris Genotypes of Contrasting Origin and Their Expression Analyses in Response to Fungal Infection.

RNA silencing serves key roles in a multitude of cellular processes, including development, stress responses, metabolism, and maintenance of genome integrity. Dicer, Argonaute (AGO), double-stranded RNA binding (DRB) proteins, RNA-dependent RNA polymerase (RDR), and DNA-dependent RNA polymerases known as Pol IV and Pol V form core components to trigger RNA silencing. Common bean (Phaseolus vulgaris) is an important staple crop worldwide. In this study, we aimed to unravel the components of the RNA-guided silencing pathway in this non-model plant, taking advantage of the availability of two genome assemblies of Andean and Meso-American origin. We identified six PvDCLs, thirteen PvAGOs, 10 PvDRBs, 5 PvRDRs, in both genotypes, suggesting no recent gene amplification or deletion after the gene pool separation. In addition, we identified one PvNRPD1 and one PvNRPE1 encoding the largest subunits of Pol IV and Pol V, respectively. These genes were categorized into subgroups based on phylogenetic analyses. Comprehensive analyses of gene structure, genomic localization, and similarity among these genes were performed. Their expression patterns were investigated by means of expression models in different organs using online data and quantitative RT-PCR after pathogen infection. Several of the candidate genes were up-regulated after infection with the fungus Colletotrichum lindemuthianum.

Screening of common bean (Phaseolus vulgaris L.) germplasm against Colletotrichum lindemuthianum inciting bean anthracnose

Common bean is the most cultivated grain legume consumed globally. It is enriched in proteins, vitamins, minerals and fiber. Anthracnose disease incited by hemibiotrophic fungi Colletotrichum lindemuthianum is the most destructive disease of common beans. The present study was carried out to evaluate 87 common bean genotypes collected from different locations against C. lindemuthianum. Screening of genotypes for anthracnose resistance aids in the identification of 22 highly resistant genotypes namely PL 1, EC-400397, Hur 137, IC-199277, IC-258273, S 2, EC-400442, KB 4, Utkarsh, Hur 15, IC-260299, PDR 14, VL 125, Amber, Arun, EC-398591, EC-121013, S 6, BR 31, IC- 328372, KB 12 and KB 6. These genotypes can act as potential donors of the resistant genes in markerassisted selection (MAS) programmes for transferring the anthracnose resistance gene(s) into the susceptible genotypes.

New cytotoxic ergosterols from a plant-associated fungus Colletotrichum magnisporum

Three new ergosterols, colletosterols A-C (1–3), together with two known analogues 4 and 5, were isolated from the endophytic fungus Colletotrichum magnisporum associated with the leaves of Rauvolfia verticillata by a bioassay-guided fractionation method. The new structures were elucidated on the basis of extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. All the ergosterols were evaluated for their cytotoxic activities against A549 and HeLa cell lines. Compounds 1–3 exhibited notable cytotoxicity with the IC50 values of 3.76–11.18 μM.

Karakterisasi Isolat Bakteri Penghasil Kitinase Dan Glukanase Serta Uji Efektifitasnya Terhadap Jamur Colletotrichum sp

Shallots as a horticultural commodity is quite important in Indonesia. Fungi anthracnose disease caused by fungus Colletotrichum sp. is one of the pathogens causing rot o n shallot plants . Therefore , an alternative control that is environmentally friendly is a ne cessity . The aim of the study was to screen the best potential isolates produc ing chitinase and glucanase of shallot- rhizosphere from Brebes, and further used to inhibit fungal pathogens. The results showed that it was obtained 8 isolates have suppression activity against Colletotrichum sp. which varied in their inhibition . The highest inhibition was produced by isolate UBS 3 (30.56%), whilst one isolate (TK 3) did not have the ability to inhibit Colletotrichum sp.

Chitin Deacetylase as a Biocatalyst for the Selective N-Acylation of Chitosan Oligo- and Polymers

Chitosans, derived from the abundant natural resource chitin, are among the most versatile and promising functional biopolymers due to their unique physicochemical properties and biological activities. These can be further improved or modified by various functionalizations, targeting both the hydroxy and amino groups. However, the chemical routes used for functionalization typically use harsh chemicals, increasing the ecological footprint of the products, tend to yield low degrees of substitution, and often lack chemoselectivity. We here report on an alternative, biocatalytic route of chitosan N-acylation using a recombinant chitin deacetylase (CDA). These enzymes are known for their ability to chemo- and regioselectively N-acetylate glucosamine oligomers, and they were recently shown to also exhibit this reverse activity toward polyglucosamine, yielding partially acetylated chitosan polymers with a nonrandom pattern of acetylation. As chitin deacetylases can possess a certain cosubstrate promiscuity, we explored the ability of a CDA from the fungus Colletotrichum lindemuthianum (ClCDA) to N-acylate glucosamine tetramers and polyglucosamines using a range of small carboxylic acids as cosubstrates. The resulting tetramers were analyzed using ultra-high-performance hydrophilic liquid chromatography-tandem mass spectrometry (UHPLC-HILIC-MS), and the kinetic parameters of the acylation reactions thus determined gave deeper insight into the limitation of the cosubstrate scope of ClCDA. Using polyglucosamines as substrates, we obtained N-propiolated chitosan polymers with high fractions of substitution of 0.7. Copper-catalyzed azide–alkyne cycloaddition (CuAAC) then yielded a fluorescence-labeled polymer, providing proof-of-principle for click functionalization of chitosans using this chemoenzymatic approach. Given the known regioselectivity of chitin deacetylases, which is retained during reverse N-acetylation, this process might give access to a broad variety of functionalized chitosans with nonrandom substitution patterns.

BIOSYNTHESIS OF GOLD NANOPARTICLES FROM FUNGI

All selected five fungi Colletotrichum fulcatum, Trichoderma atroviride, Aspergillus paraciticus. Aspergillus carbonarius and Penicillium citrinum are used for the biosynthesis of gold nanoparticles fresh cell-free filtrate was used for the synthesis of gold nanoparticles. chloroauric acid was the reductant agent mixed with cell-free filtrate of fungi. During the visible analysis, Aspergillus paraciticus biomass was changed from pale yellow to purple color, in Aspergillus carbonarius biomass was changed from black color to Purple and Penicillium citrinum pale brown color to brown color and UV-Visible spectroscopic analysis. In UV-visible spectrum, no peak formation was observed in cell-free extract Colletotrichum fulcatum, Trichoderma atroviride, Aspergillus paraciticus, Aspergillus carbonarius, and Penicillium citrinum before immersion of HAuCl4 in series 3 and 4, while as strong surface plasmon resonance (SPR) peak of the cell-free extract with HAuCl4 was observed at 450 and 550 nm.

Chitosan Coating Enriched With Ruta graveolens L. Essential Oil Reduces Postharvest Anthracnose of Papaya (Carica papaya L.) and Modulates Defense-Related Gene Expression.

Anthracnose of papaya (Carica papaya L.) caused by the fungus Colletotrichum spp. is one of the most economically important postharvest diseases. Coating with chitosan (CS) and Ruta graveolens essential oil (REO) might represent a novel eco-friendly method to prevent postharvest anthracnose infection. These compounds show both antimicrobial and eliciting activities, although the molecular mechanisms in papaya have not been investigated to date. In this study, the effectiveness of CS and REO alone and combined (CS-REO) on postharvest anthracnose of papaya fruit during storage were investigated, along with the expression of selected genes involved in plant defense mechanisms. Anthracnose incidence was reduced with CS, REO, and CS-REO emulsions after 9 days storage at 25°C, by 8, 21, and 37%, respectively, with disease severity reduced by 22, 29, and 44%, respectively. Thus, McKinney’s decay index was reduced by 22, 30, and 44%, respectively. A protocol based on reverse transcription quantitative real-time PCR (RT-qPCR) was validated for 17 papaya target genes linked to signaling pathways that regulate plant defense, pathogenesis-related protein, cell wall-degrading enzymes, oxidative stress, abiotic stress, and the phenylpropanoid pathway. CS induced gene upregulation mainly at 6 h posttreatment (hpt) and 48 hpt, while REO induced the highest upregulation at 0.5 hpt, which then decreased over time. Furthermore, CS-REO treatment delayed gene upregulation by REO alone, from 0.5 to 6 hpt, and kept that longer over time. This study suggests that CS stabilizes the volatile and/or hydrophobic substances of highly reactive essential oils. The additive effects of CS and REO were able to reduce postharvest decay and affect gene expression in papaya fruit.

Elucidation of the biochemical and molecular basis of the differential disease expression in two cultivars of chili (Capsicum annuum) in response to Colletotrichum capsici infection.

Chili plants are affected by the hemibiotrophic ascomycota fungus Colletotrichum capsici causing Anthracnose. Infection results in yield and marketability loss due to a decrease in the quality of fruits. The study of morphological symptom development in two cultivars, Bullet, and Beldanga, showed very different disease expression pattern. To understand the reasons behind such differential response, we investigated, in a time-dependent manner, biochemical activities of important defense enzymes, PR proteins, like peroxidase, polyphenol-oxidase, phenylalanine ammonia lyase, β-glucanase, chitinase, catalase, as well as phenols, flavonoids, chlorophyll and the key signaling molecule nitric oxide in their leaves. We further performed real-time nitric oxide (NO) detection studies. The results showed striking differences in the activity profile of these defense molecules through the course of the study. We monitored the gene expression levels of 12 important defense-related genes under in vivo condition. The transcription levels were mostly increased in the tolerant cultivar till 7 days post-infection (DPI), while downregulation of some of the genes were observed in the susceptible one. These data indicated that disease manifestation is a simulated response of these defense molecules which can nullify the effect of the pathogen and its products, when resistance occurs. Alternatively, the pathogen suppresses the host defense when the disease develops.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11738-021-03334-x.

Evaluation of the antifungal activity of marine actinomycetes isolates against the phytopathogenic fungi Colletotrichum siamense KA: A preliminary study for new antifungal compound discovery

Marine actinomycetes are being explored to discover potential actinomycetes that produce antifungal compounds. In a previous study, marine actinomycetes isolates from the mangrove ecosystem were found to inhibit growth of the phytopathogenic fungi Colletotrichum siamense KA. In this study, the three of these isolates with the highest antagonistic activity—SM11, SM14, and SM15—were evaluated for their antifungal activity using antibiosis assay. The fermentation was performed in SCB:PDB medium (1:1) for 6, 9, and 12 days. The results showed that SM14 was the strongest potential isolate; it inhibited the growth of C. siamense KA on average up to 64.90% for 12 days on PDA filtrate medium. Molecular identification showed SM14 was closely related to Streptomyces sanyensis, but had differences in morphological and biochemical characteristics compared to SM11 or SM15. This indicated that the three isolates were different strains and may challenge further research on identifying and analyzing their antifungal compounds.

Diatraea saccharalis harbors microorganisms that can affect growth of sugarcane stalk-dwelling fungi.

Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae), the sugarcane borer, spends most of its life cycle inside the galleries it burrows into sugarcane stalk, where two rot-causing fungi Colletotrichum falcatum (Went, 1893) and Fusarium verticillioides (Nirenberg, 1976) are commonly found. Results have shown that microbiota harbored by D. saccharalis inhibits the growth of F. verticillioides and C. falcatum. D. saccharalis larvae were collected from chemical-free field plants, and yeast and bacteria from third and fourth-instar D. saccharalis regurgitate were isolated onto appropriate media. The percentage of F. verticillioides and C. falcatum mycelial growth inhibition was recorded. Out of 32 yeast isolates, 9 exerted 30 to 40% growth inhibition of C. falcatum or F. verticillioides. When 24 bacterial isolates were confronted with rot-causing fungi, six inhibited C. falcatum growth by 30 to 60%, and 24 isolates inhibited 30 to 60% of F. verticillioides growth. Bacteria and yeast isolates were identified through DNA sequencing of part of 16S rDNA and part of ITS1-5.8S-ITS2, respectively, revealing an abundance of isolates with sequence similarity to Klebsiella and Bacillus and Meyerozyma, which have been used as biological control agents and their ability to promote plant growth has been demonstrated. We have shown that microorganisms from borer regurgitate inhibit phytopathogen growth in vitro. Still, further investigation of the possible functions of D. saccharalis-associated microorganisms may help understand their ecological role in plant-insect-phytopathogen interaction.

Fungal effector SIB1 of Colletotrichum orbiculare has unique structural features and can suppress plant immunity in Nicotiana benthamiana

Fungal plant pathogens secrete virulence-related proteins, called effectors, to establish host infection; however, the details are not fully understood yet. Functional screening of effector candidates using Agrobacterium-mediated transient expression assay in Nicotiana benthamiana identified two virulence-related effectors, named SIB1 and SIB2 (Suppression of Immunity in N. benthamiana), of an anthracnose fungus Colletotrichum orbiculare, which infects both cucurbits and N. benthamiana. The Agrobacterium-mediated transient expression of SIB1 or SIB2 increased the susceptibility of N. benthamiana to C. orbiculare, which suggested these effectors can suppress immune responses in N. benthamiana. The presence of SIB1 and SIB2 homologs was found to be limited to the genus Colletotrichum. SIB1 suppressed both (i) the generation of reactive oxygen species triggered by two different pathogen-associated molecular patterns, chitin and flg22, and (ii) the cell death response triggered by the Phytophthora infestans INF1 elicitin in N. benthamiana. We determined the NMR-based structure of SIB1 to obtain its structural insights. The three-dimensional structure of SIB1 comprises five β-strands, each containing three disulfide bonds. The overall conformation was found to be a cylindrical shape, such as the well-known antiparallel β-barrel structure. However, the β-strands were found to display a unique topology, one pair of these β-strands formed a parallel β-sheet. These results suggest that the effector SIB1 present in Colletotrichum fungi has unique structural features and can suppress pathogen-associated molecular pattern–triggered immunity in N. benthamiana.

Bacillus velezensis 83 increases productivity and quality of tomato (Solanum lycopersicum L.): Pre and postharvest assessment.

Bacillus spp. are well known plant growth promoting bacteria (PGPB) and biological control agents (BCA) due to their capacity to synthesize a wide variety of phytostimulant and antimicrobial compounds. B. velezensis 83 is a strain marketed in Mexico as a foliar biofungicide (Fungifree AB™) which has been used for biological control of five different genera of phytopathogenic fungi (Colletotrichum, Erysiphe, Botrytis, Sphaerotheca, Leveillula) in crops of agricultural importance such as mango, avocado, papaya, citrus, tomato, strawberry, blueberry, blackberry and cucurbits, among others. In this work, the potential of plant growth promotion of B. velezensis 83 was evaluated on different phenological stages of tomato plants as well as the biocontrol efficacy of B. velezensis 83 formulations (cells and/or metabolites) against B. cinerea infection on leaves and postharvest fruits. Greenhouse grown tomato plants inoculated with a high concentration (1×108 CFU/plant) of B. velezensis 83 yielded 254 tons/Ha•year of which the 64% was first quality tomato (≥100 g/fruit), while the control plants produced less than 184 tons/Ha•year with only 55% of first quality tomato. Additionally, in vitro assays carried out with leaves and fruits, shown that the B. velezensis 83 cells formulation had an efficacy of control of B. cinerea infection of ∼31% on leaves and ∼89% on fruits, while the metabolites formulation had an efficacy of control of less than 10%. Therefore, it was concluded that spores (not the metabolites) are the main antagonism factor of Fungifree AB™. The high effectivity of B. cinerea control on fruits by B. velezensis 83, opens the possibility for a postharvest use of this biofungicide.

Secondary metabolites with diversified structures from an endophytic fungus Colletotrichum gloeosporioides associated with a toxic medicinal plant Tylophora ovata

Six new secondary metabolites, including two new nor-triterpenes (1 and 2), one new sesquiterpene (4), two new α-pyrone derivatives (6 and 7), and one new natural product (5) along with two known compounds (3 and 8) were isolated from an endophytic fungus Colletotrichum gloeosporioides obtained from a toxic medicinal plant Tylophora ovata. Their structures were elucidated by spectroscopic data analyses, while their absolute configurations were determined by CD and X-ray diffraction analyses. The in vitro anti-inflammatory activities of these compounds were evaluated.

Submerged culture fermentation of Colletotrichum lindemuthianum DSM 12250 as biotechnological strategy for fungal chitin biotransformation

Chitin and its derived products have great potential in various industries, such as biomedical, pharmaceutical, food, among others, due to its biodegradability, biocompatibility, null toxicity, and versatility. At present, these compounds are obtained by extraction with physical, chemical, or enzymatic processes. The fungus Colletotrichum lindemuthianum DSM 12250 which produces the enzyme chitin deacetylase (ClCDA), is proposed as an alternative for the biotransformation of fungal chitin. Chitin with a % N-Acetylation of 63.6% was obtained from the dry mycelium of Aspergillus niger that, based on analysis of Fourier transform infrared spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC), is structurally similar to commercial chitin. During fermentation in submerged culture, chitin presence was not found to generate inhibition in microbial growth or the activity of the ClCDA. The maximum enzymatic activity was 0.910 ± 0.002 U/mL and deacetylation of 20.9% were achieved. This was possible due to the enzymatic machinery of the fungus that includes CDA, endo-chitinases, and N-acetyl hexosaminidases. These compounds contribute to decreasing the substrate complexity, obtaining chitosan with a DDA of 57.3%. Submerged culture fermentation of Colletotrichum lindemuthianum DSM 12250 with fungal chitin as substrate represents a potential alternative for integrating different steps in the extraction of chitin-derived products while contributing to a cleaner and more efficient production.