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Colletotrichum
All about the anthracnose fungus, plant pathogen, fungus pathogen, plant microbe interactions, plant disease, evolution, genomics
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Focal Effector Accumulation in a Biotrophic Interface at the Primary Invasion Sites of Colletotrichum orbiculare in Multiple Susceptible Plants

Abstract
We identified virulence-related effectors of a hemibiotrophic fungal pathogen Colletotrichum orbiculare, and found that a novel interface was generated by a biotrophic interaction between C. orbiculare and the host cucumber, in which the effectors secreted from the pathogen accumulated preferentially. The interface was located around the biotrophic primary hyphal neck. Here, we showed that C. orbiculare also developed this interface in a biotrophic interaction with melon, which belongs to Cucurbitaceae. Furthermore, C. orbiculare developed interface in the interaction with a susceptible plant, Nicotiana benthamiana, which is distantly related to Cucurbitaceae, suggesting that the spatial regulation strategy for effectors in C. orbiculare is not specific to cucumber; rather, it is conserved among the various plants that are susceptible to this pathogen.
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Strawberry foliar anthracnose assessment by hyperspectral imaging

Strawberry foliar anthracnose assessment by hyperspectral imaging | Colletotrichum | Scoop.it
Highlights

Hyperspectral imaging has proven to be an effective non-destructive method for assessing strawberry foliar anthracnose.

The incubation stage, in which symptoms are not yet visible, can be distinguished.

Several hyperspectral imaging analysis methods were investigated using 3 duplicate sets of experiments.

Significant wavelengths for strawberry foliar anthracnose are 551, 706, 750 and 914 nm.
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QTLs for resistance to anthracnose identified in two Capsicum sources

Abstract
Two SNP maps were constructed from two chili populations including Capsicum annuum ‘Bangchang’ × C. chinense ‘PBC932’, and C. baccatum ‘PBC80’ × ‘CA1316’, aiming to identify QTLs for anthracnose resistance. The ‘PBC932’-derived map contained 12 linkage groups (LG) with 214 SNPs and 824 cM coverage. The ‘PBC80’-derived map contained 12 LGs with 403 SNPs and 1270 cM coverage. Based on the ‘PBC932’ map, two QTLs corresponding to the anthracnose resistances in mature green and ripe fruit stages were identified on the same location of LG2 between two SNPs within 14 cM. Based on the ‘PBC80’ map, total five QTLs (three major and two minor QTLs) were identified in the ripe fruit stage, which corresponded to different resistance traits that were assayed by different inoculation methods [microinjection (MI) and high-pressure spray (HP)] with two different pathotypes (PCa2 and PCa3). All the three major QTLs for the resistance traits assayed by PCa2/MI, PCa3/MI, and PCa3/HP were located on LG4 between two SNP markers within 17 cM, while the two minor QTLs for the traits assayed by PCa3/MI and PCa3/HP were on LG12 and LG9 between two SNP markers within 6 and 3 cM, respectively. All the SNP markers flanking the identified QTLs will be helpful for marker-assisted selection for the anthracnose resistance traits in the chili populations derived from ‘PBC932’ and ‘PBC80’
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Characterization of Colletotrichum lindemuthianum races infecting dry edible bean in North Dakota

Abstract
Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib., is an economically important and damaging disease of dry bean (Phaseolus vulgaris L.) that can cause large reductions in yield and seed quality. Yield losses can reach 100% when contaminated seed is used, large amounts of inoculum are present, and favorable weather conditions occur during the crop cycle. Although widespread losses to anthracnose have not been observed in North Dakota, the lack of host resistance and favorable environmental conditions could lead to substantial economic losses. Additionally, numerous races of this pathogen exist and the pathogen race structure has the ability to change over time. Of the several races detected in North Dakota from 2003 to 2009, race 73 was the most prevalent. The purpose of this study was to determine the pathogen race types of C. lindemuthianum collected from dry bean samples in North Dakota from 2012 to 2014. Based on the 33 isolates collected in 2012 and 53 isolates collected in 2014, race 73 continues to be the most common race of C. lindemuthianum in North Dakota. Additionally, races 9 and 72 were identified; however, these pose little additional threat due to virulence pattern similarities with race 73.
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Diversity assessment of Colletotrichum species associated with chilli anthracnose and their characterization via species specific primers

Diversity assessment of Colletotrichum species associated with chilli anthracnose and their characterization via species specific primers | Colletotrichum | Scoop.it
Diversity assessment of Colletotrichum species associated with chilli anthracnose and their characterization via species specific primers
Serenella A Sukno's insight:

abstract

 

Anthracnose disease caused by Colletotrichum spp. is a major constraint for chilli production and storage throughout the globe. In the present study, diversity analysis and characterization ofColletotrichum species associated with the disease was carried out. Anthracnose infected chilli samples were collected from major chilli growing areas of India and twenty five isolates were selected for species identification. Pathogenicity of all the isolates was confirmed on a susceptible variety K2. The morphological characters viz., colony colour, colony topography, conidial size and shape and size of setae revealed three morphotypes. In contrast to morphological grouping, RAPD based diversity analysis clustered all isolates into two main groups and seven sub-groups. Thereafter, five different species specific primers were employed to characterize different species of Colletotrichum, of which primers specific for C. capsici, C. gloeosporioides and C. acutatum yielded positive results. The phylogenetic analysis based on sequence information of specific region of representative isolates confirmed association of three species with chilli anthracnose. These results have important implications in deciphering species level relationship of Colletotrichum with anthracnose disease in chilli by combined application of species specific PCR assay and morphological character for their routine diagnosis.

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Structure-function characterization reveals new catalytic diversity in the galactose oxidase and glyoxal oxidase family

Structure-function characterization reveals new catalytic diversity in the galactose oxidase and glyoxal oxidase family | Colletotrichum | Scoop.it
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Antagonistic activity of fungi of Olea europaea L. against Colletotrichum acutatum

Abstract
Fungi naturally present in olive trees were identified and tested for their antagonistic potential against C. acutatum. A total of 14 isolates were identified, 12 belonged to genera Alternaria, Epicoccum, Fusarium, Aspergillus, Anthinium, Chaetomium, Diaporthe, Nigrospora, one to family Xylariaceae and one was unclassified. All fungal isolates showed some inhibitory action over the growth of C. acutatum during dual culture growth, however, when agar-diffusible tests were performed only five fungal isolates caused C. acutatum growth inhibition: Alternaria sp. isolate 2 (26.8%), the fungus from Xylariaceae family (14.3%), Alternaria sp. isolate 1 (10.7%); Diaporthe sp. (10.7%), Nigrospora oryzae (3.5%). Volatile substances produced by these isolates were identified through gas-chromatography techniques, as phenylethyl alcohol, 4-methylquinazoline, benzothiazole, benzyl alcohol, lilial, galaxolide, among others. These inhibitory volatiles could play a significant role in reduction of C. acutatum expansion in olive and their study as potential biocontrol agents should be further explored.
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A highly conserved metalloprotease effector enhances virulence in the maize anthracnose fungus Colletotrichum graminicola

A highly conserved metalloprotease effector enhances virulence in the maize anthracnose fungus Colletotrichum graminicola | Colletotrichum | Scoop.it

Keywords:
Host-pathogen interaction;Protease;Chitinase;Anthracnose;Colletotrichum graminicola;fungalysin
Abstract
Colletotrichum graminicola causes maize anthracnose, an agronomically important disease with a worldwide distribution. We have identified a fungalysin metalloprotease (Cgfl) with a role in virulence. Transcriptional profiling experiments and live-cell imaging show that Cgfl is specifically expressed during the biotrophic stage of infection. To determine if Cgfl has a role in virulence, we obtained null mutants lacking Cgfl and performed pathogenicity and live microscopy assays. The appressorium morphology of the null mutants was normal but they exhibited delayed development during the infection process on maize leaves and roots, showing that Cgfl has a role in virulence. In vitro chitinase activity assays of leaves infected with wild type and null mutant strains show that in the absence of Cgfl, maize leaves exhibit increased chitinase activity. Phylogenetic analyses show that Cgfl is highly conserved in fungi. Similarity searches, phylogenetic analysis and transcriptional profiling show that C. graminicola encodes two LysM domain containing homologs of Ecp6, suggesting that this fungus employs both Cgfl mediated and LysM-protein mediated strategies to control chitin signaling. 

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Immunoassay-based Techniques for Early and Specific Detection of Latent Postharvest Anthracnose in Mango

Abstract
The postharvest anthracnose pathogen Colletotrichum gloeosporioides inciting latent or quiescent infection of mango was detected in early stages using immunoassay methods. Twenty-five pathotypes isolated from different agroclimatic zones of Tamil Nadu, Karnataka and Pondicherry, India, revealed the variation in protein profile analysis (SDS-PAGE). The polyclonal antibodies (PCA) were raised against the unfractioned mycelial protein (UMP) and a 40-kDa polypeptide present in all pathotypes. Standardization of antigen and antiserum dilutions revealed that an antigen dilution of 1 : 200 (protein concentration of 20 μg/ml) and antiserum dilution of 1 : 100 (protein concentration of 40 μg/ml raised against UMP) and 1 : 200 (protein concentration of 20 μg/ml raised against 40 kDa polypeptide) was found to be optimum for the detection of anthracnose pathogen. Both antisera detected the C. gloeosporioides antigen in enzyme-linked immunosorbent assays (ELISAs), dot immunobinding assays (DIBAs) and Western blots. The specificity in reaction was compared by isolating other Colletotrichum spp. from various hosts viz., C. lindemuthianum (beans), C. falcatum (sugarcane), C. musae (banana), C. capsici (chillies) and Botryodiplodia theobromae (mango). The antisera generated against UMP revealed the cross-reaction with other host isolates and mango stem end rot pathogen (B. theobromae). The PCA raised against 40-kDa polypeptide exhibited the specific reaction with C. gloeosporioides isolates in all the immunoassay techniques. By utilizing both PCA, the presence of latent infection was observed in healthy-looking leaves, flowers and fruits in orchard conditions. The fruit tissues recorded high absorbance values followed by flowers and leaves in all the detection methods. The ELISA technique was also useful in assessing the pathogen inoculum at various biocontrol formulations sprayed mango trees under field conditions. The fluorescent pseudomonad strains mixture (KFP1 + FP7) amended with chitin sprayed at 30-day intervals revealed the significant reduction in pathogen load than other formulations and unsprayed control.
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Synthesis and Biological Evaluation of Novel Fluorine-Containing Stilbene Derivatives as Fungicidal Agents against Phytopathogenic Fungi -

Synthesis and Biological Evaluation of Novel Fluorine-Containing Stilbene Derivatives as Fungicidal Agents against Phytopathogenic Fungi - | Colletotrichum | Scoop.it
The rising development of resistance to conventional fungicides is driving the search for new alternative candidates to control plant diseases. In this study, a series of new fluorine-containing stilbene derivatives was synthesized on the basis of our previous quantitative structure–activity relationship analysis results. Bioassays in vivo revealed that the title compounds exhibited potent fungicidal activities against phytopathogenic fungi (Colletotrichum lagenarium and Pseudoperonospora cubensis) from cucumber plants. In comparison to the previous results, the introduction of a fluorine moiety showed improved activities of some compounds against those fungi. Notably, compound 9 exhibited a control efficacy against C. lagenarium (83.4 ± 1.3%) comparable to that of commercial fungicide (82.7 ± 1.7%). For further understanding the possible mode of action of the stilbene against C. lagenarium, the effects on hyphal morphology, electrolyte leakage, and respiration of mycelial cell suspension were studied. Microscopic observation showed considerably deformed mycelial morphology. The conductivity of mycelial suspension increased in the presence of compound 9, whereas no significantly inhibitory effect on respiration was observed. Taken together, the fungicidal mechanism of this stilbene is associated with its membrane disruption effect, resulting in increased membrane permeability. These results provide important clues for mechanistic study and derivatization of stilbenes as alternative sources of fungicidal agents for plant disease control.

Via Christophe Jacquet
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IGS Minisatellites Useful for Race Differentiation in Colletotrichum lentis and a Likely Site of Small RNA Synthesis Affecting Pathogenicity

IGS Minisatellites Useful for Race Differentiation in  Colletotrichum lentis  and a Likely Site of Small RNA Synthesis Affecting Pathogenicity | Colletotrichum | Scoop.it
Colletotrichum lentis is a fungal pathogen of lentil in Canada but rarely reported elsewhere. Two races, Ct0 and Ct1, have been identified using differential lines. Our objective was to develop a PCR-probe differentiating these races. Sequences of the translation elongation factor 1α (tef1α), RNA polymerase II subunit B2 (rpb2), ATP citrate lyase subunit A (acla), and internal transcribed spacer (ITS) regions were monomorphic, while the intergenic spacer (IGS) region showed length polymorphisms at two minisatellites of 23 and 39 nucleotides (nt). A PCR-probe (39F/R) amplifying the 39 nt minisatellite was developed which subsequently revealed 1–5 minisatellites with 1–12 repeats in C. lentis. The probe differentiated race Ct1 isolates having 7, 9 or 7+9 repeats from race Ct0 having primarily 2 or 4 repeats, occasionally 5, 6, or 8, but never 7 or 9 repeats. These isolates were collected between 1991 and 1999. In a 2012 survey isolates with 2 and 4 repeats increased from 34% to 67%, while isolated with 7 or 9 repeats decreased from 40 to 4%, likely because Ct1 resistant lentil varieties had been grown. The 39 nt repeat was identified in C. gloeosporioides, C. trifolii, Ascochyta lentis, Sclerotinia sclerotiorum and Botrytis cinerea. Thus, the 39F/R PCR probe is not species specific, but can differentiate isolates based on repeat number. The 23 nt minisatellite in C. lentis exists as three length variants with ten sequence variations differentiating race Ct0 having 14 or 19 repeats from race Ct1 having 17 repeats, except for one isolate. RNA-translation of 23 nt repeats forms hairpins and has the appropriate length to suggest that IGS could be a site of small RNA synthesis, a hypothesis that warrants further investigation. Small RNA from fungal plant pathogens able to silence genes either in the host or pathogen thereby aiding infection have been reported.

Via Christophe Jacquet
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Screening sugarcane somaclones and their parent varieties against red rot (Colletotrichum falcatum) and assessment of Variability by RAPD and SSR markers

Screening sugarcane somaclones and their parent varieties against red rot (Colletotrichum falcatum) and assessment of Variability by RAPD and SSR markers | Colletotrichum | Scoop.it
Abstract

The experiment was conducted to find out red rot disease causing pathogenic reactions of somaclones (R0) and their respective parents at BSRI farm in the cropping season 2011-2012. A total number of sugarcane genotypes 24 including 4 sugarcane varieties viz. Isd 37, Isd 38, Isd 39 and also Isd 40 were inoculated to screen red rot resistant levels (R = Resistant, MR = Moderately Resistant) to susceptible levels (S = Susceptible, MS = Moderately Susceptible, HS = Highly Susceptible) after 7 months of planting. As a result, Isd 37 variety (source/parent) and its somaclones CC–37–12 and CC–37–86 were found to be resistant while 7 somaclones showed moderately resistant reaction. Furthermore, somaclones of Isd 38 variety viz. CC–38–2 as moderately resistant, CC–38–10 as moderately susceptible and also CC–11(38)–8 as susceptible reaction were recorded while Isd 38 variety showed resistant reaction. On the other hand, Isd 39 and Isd 40 source varieties with their somaclones were found as resistant reaction against red rot pathogen. Some somaclones showed different reaction from their source varieties such as moderately resistant somaclones were obtained from resistant source variety Isd 37 while somaclones CC–38–2 as moderately resistant, CC–38–10 as moderately susceptible and somaclone CC–38–8 as susceptible were obtained from resistant source variety Isd 38 against red rot pathogens respectively. Besides, some somaclones showed similar reaction from their resistant source varieties Isd 37, Isd 39 and also Isd 40. It revealed that reaction against red rot pathogen, induced somaclones showed variation with their source varieties. Red rot resistance somaclones were isolated and assessed for the presence of variability through RAPD and SSR markers. Cluster and sub cluster formation verified the presence of variability in the red rot resistance somaclones with respect to the parent.
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Identification and characterization of virulence-related effectors in the cucumber anthracnose fungus Colletotrichum orbiculare

Abstract
The anthracnose fungus Colletotrichum orbiculare invades hosts and establishes biotrophy, later switching to necrotrophy, together with the secretion of an arsenal of effectors. In this review, we describe current progress in the study of pathogen effectors. We identified three virulence-related effectors in C. orbiculare, and revealed part of the strategy for effector-mediated infection, including suppression of immunity triggered by particular effectors. The virulence-related effectors accumulate in a unique interfacial region between C. orbiculare and cucumbers around the neck of primary biotrophic invasive hyphae. We found that the secretion of effectors toward the interface involves exocytosis and SEC22-dependent ER-Golgi traffic.
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Morphological and molecular diversity of endophytic Colletotrichum gloeosporioides from tea plant, Camellia sinensis (L.) O. Kuntze of Assam, India

Morphological and molecular diversity of endophytic Colletotrichum gloeosporioides from tea plant, Camellia sinensis (L.) O. Kuntze of Assam, India | Colletotrichum | Scoop.it
Abstract
Thirty isolates of endophytic fungi were isolated from healthy asymptomatic leaves of tea plant (Camellia sinensis) and identified morphologically based on colony morphology, spore shape and size, growth and sporulation rate. Internal transcribed spacer r-DNA sequence analysis supported for molecular identification of all the isolates. Based on morphological and molecular characteristics the isolates were identified as Colletotrichum gloeosporioides. Variations on colony morphology which included the production of conidial masses, led to divide the isolates into different groups. Variations on spore size, growth rate and sporulation rate were exhibited by all the isolates. With RAPD molecular markers, genetic variations among the thirty isolates were observed. Genetic variations and relatedness among the thirty isolates were analyzed with UPGMA phylogram using NTSYS program. Two major groups were obtained among the thirty isolates. Group I comprised of 16 isolates which included three sub groups (Ia, Ib and Ic) and Group II constituted fourteen isolates and it also had three sub groups (IIa, IIb and IIc). A partial co-relationship among the isolates was established on the basis of morphological and molecular based clustering.
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Efficacy of SDHI fungicides including benzovindiflupyr against Colletotrichum species

Keywords:
apple bitter rot;benzovindiflupyr;Colletotrichum acutatum;Colletotrichum gloeosporioides;cucumber anthracnose;fungicide resistance
Abstract
Background
Colletotrichum species cause anthracnose diseases on many plants and crops. A new generation of succinate dehydrogenase inhibitors (SDHIs) was developed recently. The inhibitory activity of the five SDHI fungicides against Colletotrichum species was determined in this study.

Results
Isolates of C. gloeosporioides, C. acutatum, C. cereale, and C. orbiculare were insensitive (naturally resistant) to boscalid, fluxapyroxad, and fluopyram on YBA agar medium. In contrast, these isolates were relatively sensitive to penthiopyrad except for C. orbiculare. Most interestingly, benzovindiflupyr showed highest inhibitory activity against all of these four species. Benzovindiflupyr was effective against C. gloeosporioides and C. acutatum on apple and peach fruit as well as on cucumber plants inoculated with C. orbiculare. The sdhB, sdhC and sdhD genes encoding the subunits of fungicide-targeted succinate dehydrogenase were sequenced but despite high polymorphisms, no apparent resistance mutations were found in Colletotrichum species.

Conclusions
This is the first report on the activity of benzovindiflupyr against Colletotrichum species. The broad-spectrum efficacy of benzoyindiflupyr within the Colletotrichum genus might be exploited when designing disease management strategies against various pathogens on a wide range of crops. Other mechanism(s) than fungicide target-site modification may be responsible for differential sensitivity of Colletotrichum species to SDHI fungicides.
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Lack of evidence for sexual reproduction in field populations of Colletotrichum lentis

Lack of evidence for sexual reproduction in field populations of Colletotrichum lentis | Colletotrichum | Scoop.it
Abstract
Species in the genus Colletotrichum have mating systems that deviate from those of other genera in the Ascomycota, and for many species only the anamorph is known. The teleomorph of Colletotrichum lentis is inducible in vitro, but has not been reported in nature. A molecular population study based on amplified fragment length polymorphisms was conducted on 179 field isolates from lentil fields in the Canadian province of Saskatchewan. More than 94% similarity was observed among isolates, and 130 of 131 isolates sampled from a single field shared the same haplotype. Genotypic diversity was equal to 0.47, and association indices IA and
were significantly different from zero. A linkage between mating incompatibility group (mIG) 1 and race 0 was observed among field isolates, but F1 isolates from a cross between an mIG-1/race 0 and an mIG-2/race 1 isolate revealed free recombination of both traits. Results indicate that this fungus does not, or very rarely, sexually reproduces under field conditions.
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Distribution and characteristics of Colletotrichum spp. associated with anthracnose of strawberry in Hubei, China.

Anthracnose caused by Colletotrichum species is a serious disease of strawberry. The etiology of anthracnose of strawberry is complex, and several Colletotrichum species have been regarded as causal agents. In the present study, multi-locus (actin, β-tubulin, calmodulin, glyceraldehyde-3-phosphate dehydrogenase and chitin synthase) phylogenetic analysis revealed that 100 isolates of Colletotrichum associated with anthracnose of strawberry in central China belong to five species. In total, 97 isolates were identified belonging to the C. gloeosporioides species complex, with C. murrayae, C. gloeosporioides, C. fructicola, and C. aenigma accounting for 81%, 8%, 4% and 4% of the total isolates, respectively. Three isolates belonging to the C. acutatum complex were identified as C. nymphaeae. On inoculated strawberry plants, isolates of C. fructicola and C. murrayae species showed strong pathogenicity to both leaves and petioles of strawberry, with plant mortality 30 days after inoculation of 77.8% and 55.6%, respectively. C. gloeosporioides, C. aenigma and C. nymphaeae showed strong pathogenicity to leaves, but weak pathogenicity to petioles, with plant mortality 30 days after inoculation of 5.6%, 16.7% and 11.1%, respectively. The five species were divided into four classes based on their maximum growth temperatures. Isolates of C. murrayae and C. gloeosporioides were more tolerant to high temperature (>34°C) than isolates of other species, followed by C. fructicola and C. aenigma. Isolates of C. nymphaeae, which are only distributed in areas of higher altitude (1100 m), were highly sensitive to higher temperature. These results indicate that pathogenicity and adaptation to temperature are important factors in the distribution of Colletotrichum species on strawberry plants. This research may increase our understanding of how Colletotrichum spp. emerge and spread to geographical regions with different latitudes or elevations.
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Carbon regulation of environmental pH by secreted small molecules that modulate pathogenicity in phytopathogenic fungi

Carbon regulation of environmental pH by secreted small molecules that modulate pathogenicity in phytopathogenic fungi | Colletotrichum | Scoop.it
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Anthracnose Control for Mango Farmers

This short film is for mango farmers. It shows how to identify and control Anthracnose. The film was shoot in the Brong Ahafo Region in Ghana in collaboratio...
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Antifungal Activity of a Synthetic Cationic Peptide against the Plant Pathogens Colletotrichum graminicola and Three Fusarium Species

Antifungal Activity of a Synthetic Cationic Peptide against the Plant Pathogens Colletotrichum graminicola and Three Fusarium Species | Colletotrichum | Scoop.it
Abstract
A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of 50 μg/ml, although one isolate of Fusarium oxysporum was inhibited at 5 μg/ml of JH8944. Most conidia of Fusarium graminearum were killed within 6 hours of treatment with 50 μg/ml of JH8944. Germinating F. graminearum conidia required 238 μg/ml of JH8944 for 90% growth inhibition. The peptide did not cause any damage to tissues surrounding maize leaf punctures when tested at a higher concentration of 250 μg/ml even after 3 days. Liposomes consisting of phosphatidylglycerol were susceptible to leakage after treatment with 25 and 50 μg/ml of JH8944. These experiments suggest this peptide destroys fungal membrane integrity and could be utilized for control of crop fungal pathogens.

Keywords: antifungal peptide, membrane-active mechanism, non-phytotoxic
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Cytogenomic characterisation of Colletotrichum kahawae, the causal agent of Coffee Berry Disease, reveals diversity in minichromosome profiles and genome size expansion

Cytogenomic characterisation of Colletotrichum kahawae, the causal agent of Coffee Berry Disease, reveals diversity in minichromosome profiles and genome size expansion | Colletotrichum | Scoop.it
Keywords:
Coffee Berry Disease; Colletotrichum kahawae ;Colletotrichum gloeosporioides species complex;Cytogenomics;genome size;minichromosomes
Abstract
Colletotrichum kahawae is an emerging fungal pathogen, which has recently undergone a speciation process from a generalistic “C. gloeosporioides species complex” background by acquiring the unique capacity to infect green coffee berries, thus causing Coffee Berry Disease. This is a severe and widespread disease in Africa and an eminent threat to Arabica coffee cultivation in Asia and America, if the pathogen enters those continents. Genetic diversity within C. kahawae is low although geographically structured, but notorious differences in pathogen aggressiveness are not explainable by phylogeography. In this work we have characterised two cytogenomic traits (genome size and minichromosome profiles) of a collection of C. kahawae isolates (representing the breadth of its genetic diversity and distinct aggressiveness classes) along with closely related taxa. The results obtained constitute the first flow cytometry-based genome size estimation in the genus Colletotrichum and evidence a ca. 8 Mbp genome size expansion between C. kahawae (79.5 Mbp in average) and its closest relatives (71.3 Mbp), corroborating evidence indicating that C. kahawae (i.e., the Coffee Berry Disease pathogens) should remain regarded as a distinct species. Results have also shown the presence of 2-5 minichromosomes in C. kahawae, suggesting a positive relationship between the number of minichromosomes and the level of aggressiveness of the different isolates analysed, while no correlation could be established between aggressiveness and whole genome size. Overall, these results may be the basis for the identification of pathogenicity/aggressiveness-related factors in such minichromosomes, and may provide clues to the characterisation of specific markers for aggressiveness classes.
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A fungal effector with host nuclear localization and DNA-binding properties is required for maize anthracnose development

A fungal effector with host nuclear localization and DNA-binding properties is required for maize anthracnose development | Colletotrichum | Scoop.it
Plant pathogens have the capacity to manipulate the host immune system through the secretion of effectors. We identified 27 putative effector proteins encoded in the genome of the maize anthracnose pathogen Colletotrichum graminicola that are likely to target the host’s nucleus as they simultaneously contain sequence signatures for secretion and nuclear localization. We functionally characterized one protein identified as CgEP1. This protein is synthesized during the early stages of disease development and is necessary for anthracnose development in maize leaves, stems and roots. Genetic, molecular and biochemical studies confirmed that this effector targets the host’s nucleus, and defines a novel class of dsDNA-binding protein. We show that CgEP1 arose from a gene duplication in an ancestor of a lineage of monocot-infecting Colletotrichum spp. and has undergone an intense evolution process with evidence for episodes of positive selection. We detected CgEP1 homologs in several species of a grass infecting lineage of Colletotrichum spp. suggesting that its function may be conserved across a large number of anthracnose pathogens. Our results demonstrate that effectors targeted to the host nucleus may be key elements for disease development, and aid in the understanding of the genetic basis of anthracnose development in maize plants.
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The complete mitochondrial genome sequence of the ascomycete plant pathogen Colletotrichum acutatum

The complete mitochondrial genome sequence of the ascomycete plant pathogen Colletotrichum acutatum | Colletotrichum | Scoop.it
Abstract
Collectotrichum acutatum is a fungal plant pathogen that causes pre- and post-harvest anthracnose on a wide range of plants worldwide. The complete mitochondrial genome of C. acutatum has been determined for the first time. This study revealed that the mitogenome of C. acutatum is a closed circular molecule of 30 892 bp in length, with a G + C content of 34.7%, which include 15 protein-coding genes, 22 tRNA genes, and two rRNA genes. All the protein-coding genes, accounting for 46.6% of the C. acutatum mitogenome, start with the standard ATG codon and end with the TAA termination codon except for nad6 gene using the TAG termination codon. The mitogenome information of C. acutatum can provide molecular basis for further studies on molecular systematics and evolutionary dynamics.
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