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Papaya fruit cv. Maradol showing typical symptoms of anthracnose were observed in a commercial orchard located in the municipality of Pinotepa Nacional at the coastal region of Oaxaca, Mexico in September 2020. The incidence rate of anthracnose reached 60%. The symptoms consisted of sunken, water-soaked lesions with salmon-coloured conidia masses on the surface of papaya fruit. The aim of this study was to identify the causal agent of papaya anthracnose based on the phylogenetic analysis of four concatenated datasets. The isolate exhibited sparse white to greyish aerial mycelium and clearly shaped concentric rings with exudate of orange conidia on potato dextrose agar. The fungus was identified as Colletotrichum brevisporum using sequence data of the internal transcribed spacer (ITS) region, and part of the actin (act), glyceraldehyde-3-phosphate dehydrogenase (gapdh), and chitin synthase (chs-1) genes. The fungus isolated from diseased fruit produced lesions on wounded fruit and unwounded fruit. The pathogen was re-isolated from lesions on inoculated fruit to fulfill Koch's postulates. To our knowledge, this is the first report of C. brevisporum causing anthracnose disease on papaya fruit in Mexico. [ABSTRACT FROM AUTHOR]

Bletilla striata is a traditional Chinese medicine plant. Guizhou Province is the largest producer of B. striata, with the biggest cultivation area and highest yield in China. Anthracnose is the main disease affecting the crop. In July 2021, an anthracnose outbreak occurred in Shibing County, Guizhou Province, seriously affecting the yield and quality of B. striata. Thirty samples of B. striata anthracnose were collected from Shuangjing, Niudachang, and Yangliutang towns in three main planting areas of Shibing County to clarify the causal agent of B. striata anthracnose. Fifty anthracnose strains were isolated by tissue isolation and single-conidium culture. Through morphological observation and multigene phylogenetic analysis of the internal transcribed spacer, actin, beta-tubulin, glyceraldehyde-3-phosphate dehydrogenase and chitin synthase genes, the isolated strains were identified as Colletotrichum spaethianum. The infection process of C. spaethianum on B. striata leaves was observed by cell tissue staining. The results showed that at 25°C, the conidia of C. spaethianum on B. striata leaves began to germinate after 3 h, and the peak period of conidia germination was 8 h. Appressoria formation peaked after 24 h. During 48–72 h, the hyphae randomly expanded horizontally and vertically on the host surface, gradually forming a reticular distribution. This study is the first report of C. spaethianum causing anthracnose in B. striata. Our study clarifies the infection and development process of C. spaethianum on B. striata leaves, thus providing a theoretical basis for further study on the monitoring of B. striata anthracnose. [ABSTRACT FROM AUTHOR]

Cynanchum paniculatum is a valuable medicinal herb used for the effective treatment of various human ailments. A severe anthracnose disease of C. paniculatum was recently observed in Tai'an, China, which caused considerable economic losses in this main herb-growing region of northern China. Infected plants had conspicuous symptoms consisting of circular brown lesions on the leaves and pods, as well as light brown cankers with dark spines on the stem surface. Fungi were isolated from diseased plant tissues, which exhibited radial colony morphology with dense white mycelial growth on potato dextrose agar. Through morphological observation and multigene sequencing analysis of the ITS region and actin, β-tubulin and histone genes, the isolated fungi were identified as Colletotrichum truncatum. Pathogenicity tests were conducted resulting in symptoms on C. paniculatum similar to those seen in the field. Considering the fungal species in the genus Colletotrichum are major phytopathogens that can cause serious anthracnose diseases on numerous crop species, the pathogenicity of an isolate of C. truncatum was assessed on multiple plant species. This is the first report of C. truncatum causing anthracnose of the Chinese medicinal herb C. paniculatum. [ABSTRACT FROM AUTHOR]

Colletotrichum lentis is an important pathogen of lentils in Canada causing the disease anthracnose. Fungicide applications are an important tool for the control of this disease and, historically, QoI fungicidegdels have been used intensively. Reduced field efficacy of QoI fungicides on C. lentis has been reported recently and could be linked to the presence of QoI resistant isolates. In this study, the cytochrome b gene of C. lentis was sequenced, and the mutation G143A was identified as the causal resistance mechanism. Furthermore, a sensitive and reliable molecular biological assay was developed for the quantitative detection of the G143A mutation by pyrosequencing in field samples. [ABSTRACT FROM AUTHOR]

Colletotrichum higginsianum is an economically important anthracnose pathogen of crucifers that causes losses worldwide. For comprehensive control of anthracnose disease, it is essential to understand the mechanisms of pathogenicity in C. higginsianum. The Ser/Thr kinase Sch9 belonging to the AGC (protein kinase A, G, and C) kinase family, commonly found in eukaryotes, plays a vital role in various cell signalling pathways and development. However, it has not been studied in Colletotrichum species. Three domains, Protein kinase C conserved region 2 (C2), Serine/Threonine protein kinase catalytic (S_TKc) and Extension to Ser/Thr-type protein kinases (S_TK_X), were identified in the C. higginsianum Sch9 (ChSch9) protein. Phylogenetic analysis indicated that ChSch9 is closely related to the AGC kinase family, which is conserved in fungi. Deletion of ChSch9 caused defects in hyphal morphology, growth and conidiation. In addition, deletion of ChSch9 was associated with reduced tolerance to hyperosmotic, cell wall and oxidative stresses in C. higginsianum, and ChSch9 deletion mutants were more tolerant to heat. Furthermore, we found that ChSch9 might be involved in the pyruvate–acetaldehyde fermentation pathway. Importantly, deletion of ChSch9 led to a reduction in appressoria and infective hyphae formation, resulting in defects in virulence. Collectively, the results of this study indicate that ChSch9 is required for infection-related morphogenesis and virulence in C. higginsianum. [ABSTRACT FROM AUTHOR]

The presence of well-defined and depressed circular leaf spots, dark in their core and surrounded by a light brown dim halo, was observed on Dendrobium nobile plants in the municipality of Ixtaczoquitlán, state of Veracruz, Mexico, in 2019. Colletotrichum isolates were consistently obtained from symptomatic plants of D. nobile. The morphological characteristics of these isolates resembled each other, and their pathogenicity could be confirmed based on the necrotic lesions caused by three of these isolates on D. nobile plants 10 days after inoculation. The causal agent of this disease was identified as Colletotrichum karstii, based on morphological characteristics and the partial sequences of the ITS1-5.8S-ITS2, calmodulin and β-tubulin genes of the DNA of three representative isolates(CKFG004, CKFG005 and CKFG006). To our knowledge, this is the first report which identifies C. karstii as the causal agent of anthracnose of D. nobile leaves in Mexico. [ABSTRACT FROM AUTHOR]

Anthracnose was observed on postharvest avocados (Persea americana) in a commercial market in Jinju, South Korea, in 2019. Symptoms included soft rot and sunken lesions leaking necrotic fluid. Orange conidial masses were observed on the outer surfaces of these unappealing avocados. Colletotrichum fungi producing grey to olive colonies with orange conidial masses were consistently recovered from the lesions on the avocados. The aim of this study was to isolate and identify the causative pathogen. Koch's postulates were completed by conducting pathogenicity tests on avocado fruit and wounded green Arabica coffee (Coffea arabica) berries. The symptoms induced artificially on avocado fruit were the same as those of the original infections, whereas negative control avocados were asymptomatic. The fungus associated with this anthracnose produced lesions on wounded coffee berries, but not on unwounded berries. Using morphological characterization, pathogenicity testing, and partial sequencing of the internal transcribed spacer (ITS) rDNA region and the glutamine synthetase (GS) gene, the fungus was identified as Colletotrichum kahawae subsp. ciggaro B. Weir & P.R. Johnst. The results of this study are expected to provide important information for avocado transportation and quarantine. [ABSTRACT FROM AUTHOR]

Among lentil diseases reported from around the world, anthracnose caused by the fungal ascomycete pathogen Colletotrichum lentis is either not mentioned, or listed as a minor disease. In Canada, it was originally found in Manitoba in 1987, where most lentil was grown at the time, and within 3 years was also detected in Saskatchewan as lentil production moved westwards. Since then, anthracnose has become the most important foliar disease on lentil in western Canada. Originally described as C. truncatum, isolates from lentil were designated their own species in the ‘destructivum’ clade in 2014. Two sexual incompatibility groups have been identified in the Canadian population, but both harbour MAT1-2 while lacking MAT1-1, so sexual mating does not follow the classical ascomycete system of heterothallic species. Field data indicate that the pathogen primarily reproduces asexually, but readily mates in the laboratory, so it may have facultative sexuality. The pathogen has a hemibiotrophic lifestyle with a brief biotrophic phase followed by necrotrophy. Two pathogenic races have been described and partial resistance to the less virulent race 1 was found in cultivated lentil species. High levels of resistance to the virulent race 0 have only been identified in the related species Lens ervoides, and was introgressed into cultivated lentil. Using an ascospore-derived population developed from a cross between race 1 and race 0 isolates, one QTL for virulence was identified on one of the 12 chromosomes of C. lentis. [ABSTRACT FROM AUTHOR]

Colletotrichum lentis causes anthracnose of lentil (Lens culinaris) in Canada that results in defoliation, stem girdling and severe yield losses, but the disease is rarely reported elsewhere. The pathogen survives as microsclerotia on lentil debris for up to 3 years when buried in the soil, but loses viability on the soil surface. Windborne debris spreads the pathogen to neighbouring fields, while seedborne infection is less important. Foliar fungicides were registered, and a fungicide decision support system was developed which assessed disease risk with 85% accuracy. Around 2300 L. culinaris accessions from 50 countries were screened for resistance. Congruently, two races - Ct1 and Ct0 - were identified on differential lentil lines. Resistant lines were generated by cycles of inoculation and selfing of single resistant plants which resulted in the following three accessions resistant to both races: VIR2633 (Georgia), VIR2058 and VIR2076 (Czech Republic), while six and 49 lines had resistance to Ct0 and Ct1, respectively. Ct1 resistance is controlled by recessive and dominant genes crt1 and CtR3 in variety ‘Indianhead’, ctr2 and CtR5 in accession PI345629 and CtR4 in PI320937. Molecular markers linked to Ct1 resistance were identified on linkage group six, close to Ascochyta lentis resistance, and were used to combine resistance to both pathogens in breeding lines. Two repeat rich regions in the intergenic spacer (IGS) of ribosomal DNA can be used to differentiate the two C. lentis races. Utilizing length polymorphisms in a 39 nucleotide repeat region showed the races were equally frequent among isolates collected between 1991 and 1999, while 95% belonged to race Ct0 in 2010, likely because lentil varieties are susceptible to race Ct0, but around one-third of the varieties had Ct1 resistance. [ABSTRACT FROM AUTHOR]

Passion fruit (Passiflora edulis Sims.) has become an important commercial fruit with large-scale cultivation in China. A disease affecting the stems, fruits, leaves and tendrils was observed on passion fruit vines in Sanming, Fujian Province, China, in August 2015. The typical symptoms included lesions of oval to irregular shapes, brown to brownish black in colour, with sunken cavities. Acervuli and dark setae were observed within the lesions. The disease incidence varied from 25 to 60% in different fields. The causative pathogen was identified as Colletotrichum brevisporum on the basis of morphological characteristics and sequence analysis of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-tubulin 2 (Tub2) and actin (ACT) genes. Pathogenicity was confirmed by fulfilling Koch’s postulates on plants and detached fruit. To our knowledge, this is the first report of anthracnose disease on passion fruit caused by C. brevisporum worldwide. [ABSTRACT FROM AUTHOR]

A severe disease was observed on pumpkin (Cucurbita moschata) in Beijing, China during 2009–2011. The causal agent was isolated from infected tissues, and its pathogenicity was confirmed. The pathogen was identified asColletotrichum capsici(Syd.) Butler based on morphological characters and molecular methods. This is the first report ofC. capsicicausing anthracnose of pumpkin in China. [ABSTRACT FROM AUTHOR]

The fungal pathogen Colletotrichum truncatum is a potential bioherbicide agent for management of the noxious weed scentless chamomile (Metricaria perforate) in western Canada. Isolates of the potential biocontrol agent from scentless chamomile cannot be separated morphologically from the pathogen that causes anthracnose on lentil and field pea, raising questions about crop safety for its use as a bioherbicide agent in the region. Internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) of C. truncatum from scentless chamomile and several crop species were examined for genetic differences. ITS-rDNA fragments of 63 isolates were amplified using the universal primers Its4 and Its5 and sequenced. The rDNA fragment was 571 bp in size for isolates from scentless chamomile, 566 bp from lentil, 558 or 559 bp from field pea isolates and 555 bp from soybean. Phylogenetic analysis using parsimony and neighbour-joining methods separated these putative C. truncatum isolates into four groups that coincided with host origin. All of the isolates of scentless chamomile fell within a single cluster regardless of their geographic origins, and were most closely related to C. truncatum isolates from lentil. Morphologically, the isolates from scentless chamomile, lentil and field pea were similar in conidial shape and dimension, whereas soybean isolates had substantially longer and more falcate conidia and slightly bigger appressoria. Based on the sequence information, strain-specific PCR primers were designed for isolates of C. truncatum from each host and used to amplify specific rDNA fragments (markers). This molecular technique was sensitive and strain-specific for detection and differentiation of Colletotrichum isolates from scentless chamomile, lentil, field pea and soybean, and may be used as a tracking and monitoring tool in environmental risk assessment for the bioherbicide agent. [ABSTRACT FROM AUTHOR]

The article discusses the study that investigates the host specificity of Colletotrichum truncatum (CT) from weed scentless chamomile in western Canada. The study was conducted by understanding the risk, potential infection strategy and biocontrol agents of chamomiles, and their cross infection was observed through inoculation. The study reveals the absence of infection structures from the lentil leaves which depict the absence of endophytic colonization and infection during incubation.

The article discusses a study on the host ranges of Colletotrichum trancatum isolates from lentil. The study assessed leguminous species through controlled conditions and field trials, and the seed of every plant variety was planted individually in plastic pots in a soil-less potting mixture. Accordingly, chosen plant species were evaluated for their response to C. truncatum races from lentil. Results show that there was no substantive distinction in the host ranges of two C. truncantum races.

The article presents abstracts of plant pathological research. They include "Crop-management effects on leaf spots of spring wheat in eastern Saskatchewan" "Differentiation and detection of Colletotrichum truncatum isolates by strain-specific PCR markers" and "Effect of crucifer phytoalexins on zoospore emergence and appressoria formation of germ tubes of Albugo candida."

The article describes the development of real-time polymerase chain reaction (PCR) assay quantification of biocontrol agent Colletotrichum coccodes DNA in soils from bioherbicide field-release assays with normalization for PCR inhibition. The analysis estimating the PCR efficiency on a sample per sample basis in 18 soil DNA extracts was realized through comparing the estimated quantities of the external control and the known quantities added to the extracts.

Examines how defined soil moisture and temperature, typical of strawberry nursery fields during the winter, affect the survival of Colletotrichum acutatum, the causal agent of strawberry anthrachose, in strawberry residue over time. Determination of the survival of the pathogen from the number of recovered conidia and the percent conidial germination; Conidial recovery from stolons; Indication that C. acutatum may survive the relatively short winter fallow season in strawberry nursery soil in California.

The article presents abstracts related to plant diseases including the "Role of ammonia secretion and pH modulation on pathogenicity of Colletotrichum coccodes on tomato fruit," by N. Alkan and colleagues, "A critique of studies evaluating glyphosate effects on diseases associated with Fusarium spp.," by J.R. Powell and C.J. Swanton, and "Suppression of bacterial canker of tomato by composts," by A. Yogev and colleagues.

Discusses the abstract of the paper "Submerged fermentation of Colletotrichum truncatum for biological control of scentless chamomile," by F.L. Dokken et al, presented during the joint regional meeting of the Alberta and Saskatchewan units of the Canadian Phytopathology Society in 2003.

Reports on the importance of an examination of disease progression by quantifying the amount of fungal biomass in infected host tissues in the study of fungal-plant interactions. Use of the green fluorescent protein (GFP) from the jellyfish, Aequorea victoria; Transformation of strains of Colletotrichum destructivum O'Gara and C. orbiculare with a modified GFP gene to develop a quantitative assay of fungal growth inside plant tissues.

Discusses the abstract of the paper "Identification of two races of Collectrichum truncatum in Saskatchewan," by K.L. Anderson et al, presented during the joint regional meeting of the Alberta and Saskatchewan units of the Canadian Phytopathology Society in 2003.

Discusses the abstract of the article "The role of nitric oxide in conidial germination and appressorial development in Colletotrichum coccodes," by J. Wang and V.J. Higgins, submitted to the 2003 Canadian Phytopathological Society Annual Meeting in Montreal, Quebec.

Discusses the abstract of the article "The significance of ethylene in the interaction between Nicotiana tabacum and Colletotrichum destructivum," by N. Chen, P.H. Goodwin and T. Hsiang, submitted to the 2003 Canadian Phytopathological Society Annual Meeting in Montreal, Quebec.