Molecular diversity of anthracnose pathogen populations associated with UK strawberry production suggests multiple introductions of three different Colletotrichum species.

Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production

Hosts of Colletotrichum

The taxonomy of Colletotrichum has undergone profound changes over the past decade, with ca. 340 species now recognised, and grouped into 20 species complexes (16 previously described and four proposed in this work). Over that period, the volatility of the taxonomic framework posed difficulties to the aetiology of anthracnose diseases along with uncertainty on cross-infection potential, quarantine rules, pesticide management and plant breeding strategies. Now that the Colletotrichum taxonomy is stabilising (still several new species being named, but no longer representing major pathogens), there is a point on reviewing the knowledge on the aetiology of anthracnose diseases in a global way, pointing out the relative importance of each Colletotrichum species for each host/crop and identifying areas/crops where information is missing (and there are several crops for which nothing is known regarding Colletotrichum species in modern terms). Based on 3400 host species-Colletotrichum species occurrence records (considering only records of Colletotrichum spp. identified in modern terms), we have listed over 760 host (plants) species and analysed the information available on the Colletotrichum species reported from them, the symptoms caused and the geographic distribution and pathological relevance. Whereas some of these hosts are wild plants, this work is mostly focused on cultivated plants and therefore on the aetiology of anthracnose diseases globally. In the context of Colletotrichum fungi, this compilation provides downstream users of Mycology, namely those in areas such as Plant Pathology, Plant Protection and Plant Breeding, with updated information on the main causal agents of anthracnose in each crop/plant species in each location, or alternatively with an alert on the lack of information on the identity of the species of Colletotrichum relevant for a given crop in a given location.info:eu-repo/semantics/publishedVersio

Morphological, Pathological, and Genetic Diversity of Colletotrichum Species Pathogens on Solanaceous Vegetable Crops in Bulgaria

Colletotrichum species are among the most devastating plant pathogens in a wide range of hosts. Their accurate identification requires a polyphasic approach, including geographical, ecological, morphological, and genetic data. Solanaceous crops are of significant economic importance for Bulgarian agriculture. Colletotrichum-associated diseases pose a serious threat to the yield and quality of production but are still largely unexplored. The aim of this study was to identify and characterize 26 pathogenic Colletotrichum isolates that threaten solanaceous crops based on morphological, pathogenic, and molecular data. DNA barcodes enabled the discrimination of three main taxonomic groups: C. acutatum, C. gloeosporioides, and C. coccodes. Three different species of acutatum complex (C. nymphaeae, C. godetiae, and C. salicis) and C. cigarro of the gloeosporioides complex were associated with fruit anthracnose in peppers and tomatoes. The C. coccodes group was divided in two clades: C. nigrum, isolated predominantly from fruits, and C. coccodes, isolated mainly from roots. Only C. salicis and C. cigarro produced sexual morphs. The species C. godetiae, C. salicis, and C. cigarro have not previously been reported in Bulgaria. Our results enrich the knowledge of the biodiversity and specific features of Colletotrichum species, which are pathogenic to solanaceous hosts, and may serve as a scientific platform for efficient disease control and resistance breeding

Weeds as potential inoculum reservoir for Colletotrichum nymphaeae causing strawberry anthracnose in Iran and Rep-PCR fingerprinting as useful marker to differentiate C. acutatum complex on strawberry

3openInternationalInternational coauthor/editorStrawberry anthracnose caused by Colletotrichum spp. is considered one of the most serious and destructive disease of strawberry worldwide. Weeds, as possible hosts of the pathogen, could have a role as potential inoculum reservoir. To prove this hypothesis, symptomless weeds were collected in strawberry fields showing anthracnose symptoms in Iran. Ten isolates with Colletotrichum-like colonies were recovered from symptomless Amaranthus viridis L., Convolvulus arvensis L., Fumaria officinalis L., Lactuca serriola L., and Sonchus oleraceus L. plants. The isolates were identified as C. nymphaeae, based on a combination of morphological and sequence data of TUB and GADPH genes. This identification was further validated using Rep-PCR fingerprinting analysis, which produces species-specific DNA fingerprints and unveils inter and intra variation of the species examined in this study. Moreover, rep-PCR marker was used to reveal accurate taxonomic position of Colletorichum spp. causing strawberry anthracnose belonging to the C. acutatum complex, including C. acutatum sensu stricto, C. fiorinae, C. godetiae, C. nymphaeae, C. salicis, and C. simmondsii. The C. nymphaeae isolates originating from symptomless weeds confirmed their pathogenicity on detached strawberry, proving that weeds in strawberry field may have a role as reservoir of inoculum. However, further studies are necessary to quantify their actual contribution to anthracnose epidemics in strawberry fields.openKarimi, Kaivan; Arzanlou, Mahdi; Pertot, IlariaKarimi, K.; Arzanlou, M.; Pertot, I

Colletotrichum species associated with anthracnose of Pyrus spp. in China

Colletotrichum species are plant pathogens, saprobes, and endophytes on a range of economically important hosts. However, the species occurring on pear remain largely unresolved. To determine the morphology, phylogeny and biology of Colletotrichum species associated with Pyrus plants, a total of 295 samples were collected from cultivated pear species (including P. pyrifolia, P. bretschneideri, and P. communis) from seven major pear-cultivation provinces in China. The pear leaves and fruits affected by anthracnose were sampled and subjected to fungus isolation, resulting in a total of 488 Colletotrichum isolates. Phylogenetic analyses based on six loci (ACT, TUB2, CAL, CHS-1, GAPDH, and ITS) coupled with morphology of 90 representative isolates revealed that they belong to 10 known Colletotrichum species, including C. aenigma, C. citricola, C. conoides, C. fioriniae, C. fructicola, C. gloeosporioides, C. karstii, C. plurivorum, C. siamense, C. wuxiense, and two novel species, described here as C. jinshuiense and C. pyrifoliae. Of these, C. fructicola was the most dominant, occurring on P. pyrifolia and P. bretschneideri in all surveyed provinces except in Shandong, where C. siamense was dominant. In contrast, only C. siamense and C. fioriniae were isolated from P. communis, with the former being dominant. In order to prove Koch's postulates, pathogenicity tests on pear leaves and fruits revealed a broad diversity in pathogenicity and aggressiveness among the species and isolates, of which C. citricola, C. jinshuiense, C. pyrifoliae, and C. conoides appeared to be organ-specific on either leaves or fruits. This study also represents the first reports of C. citricola, C. conoides, C. karstii, C. plurivorum, C. siamense, and C. wuxiense causing anthracnose on pear.Earmarked Fundhttps://www.ingentaconnect.com/content/nhn/pimjhj2020BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Weeds as Potential Inoculum Reservoir for Colletotrichum nymphaeae Causing Strawberry Anthracnose in Iran and Rep-PCR Fingerprinting as Useful Marker to Differentiate C. acutatum Complex on Strawberry

Strawberry anthracnose caused by Colletotrichum spp. is considered one of the most serious and destructive disease of strawberry worldwide. Weeds, as possible hosts of the pathogen, could have a role as potential inoculum reservoir. To prove this hypothesis, symptomless weeds were collected in strawberry fields showing anthracnose symptoms in Iran. Ten isolates with Colletotrichum-like colonies were recovered from symptomless Amaranthus viridis L., Convolvulus arvensis L., Fumaria officinalis L., Lactuca serriola L., and Sonchus oleraceus L. plants. The isolates were identified as C. nymphaeae, based on a combination of morphological and sequence data of TUB and GADPH genes. This identification was further validated using Rep-PCR fingerprinting analysis, which produces species-specific DNA fingerprints and unveils inter and intra variation of the species examined in this study. Moreover, rep-PCR marker was used to reveal accurate taxonomic position of Colletorichum spp. causing strawberry anthracnose belonging to the C. acutatum complex, including C. acutatum sensu stricto, C. fiorinae, C. godetiae, C. nymphaeae, C. salicis, and C. simmondsii. The C. nymphaeae isolates originating from symptomless weeds confirmed their pathogenicity on detached strawberry, proving that weeds in strawberry field may have a role as reservoir of inoculum. However, further studies are necessary to quantify their actual contribution to anthracnose epidemics in strawberry fields

Colletotrichum Species Associated with Apple Bitter Rot and Glomerella Leaf Spot: A Comprehensive Overview

Species of the genus Colletotrichum are among the most important plant pathogens globally, as they are capable of infecting many hosts—apple (Malus spp.) and other fruit and woody plant species—but also vegetable crops, cereals, legumes, and other annual and perennial herbaceous plants. The apple (Malus spp.) is attacked by various species from the genus Colletotrichum, whereby 27 different species from this genus have been described as the causative agents of apple bitter rot (ABR) and 15 as the cause of Glomerella leaf spot (GLS). These species generally belong to one of three species complexes: Colletotrichum acutatum, Colletotrichum gloeosporioides, and Colletotrichum boninense. The largest number of apple pathogens of the genus Colletotrichum belong to the species complex C. acutatum and C. gloeosporioides. However, further data on these species and the interactions between the species complexes of the genus Colletotrichum that cause these two apple diseases is needed for the development of effective control measures, thus ensuring successful and profitable apple cultivation. To contribute to this endeavor, a comprehensive review of the causative agents of ABR and GLS from the genus Colletotrichum is provided. In addition to presenting the species’ current names, distribution, economic significance, and the symptoms they cause in apple, their development cycle, epidemiology, and molecular detection strategies are described, with a particular emphasis on control measures

Morphological, Pathological and Genetic Diversity of the Colletotrichum Species, Pathogenic on Solanaceous Vegetable Crops in Bulgaria

Colletotrichum species are among the most devastating plant pathogens in a wide range of hosts. Their accurate identification requires a polyphasic approach, including geographical, ecological, morphological, and genetic data. Solanaceous crops are of significant economic importance for Bulgarian agriculture. Colletotrichum-associated diseases pose a serious threat to the yield and quality of production but are still largely unexplored. The aim of this study was to identify and characterize 26 pathogenic Colletotrichum isolates that threaten solanaceous crops based on morphological, pathogenic, and molecular data. DNA barcodes enabled the discrimination of three main taxonomic groups: C. acutatum, C. gloeosporioides, and C. coccodes. Three different species of acutatum complex (C. nymphaeae, C. godetiae, and C. salicis) and C. cigarro of the gloeosporioides complex were associated with fruit anthracnose in peppers and tomatoes. The C. coccodes group was divided in two clades: C. nigrum, isolated predominantly from fruits, and C. coccodes, isolated mainly from roots. Only C. salicis and C. cigarro produced sexual morphs. The species C. godetiae, C. salicis, and C. cigarro have not previously been reported in Bulgaria. Our results enrich the knowledge of the biodiversity and specific features of Colletotrichum species, which are pathogenic to solanaceous hosts, and may serve as a scientific platform for efficient disease control and resistance breeding

Colletotrichum acutatum sensu lato : from diversity study to genome analysis

Colletotrichum acutatum sensu lato includes a number of important pathogens that cause economically significant losses of various crops. The C. acutatum species complex has a wide host range in both domesticated and wild plant species, and its capability to infect different types of hosts such as insects has also been described. Members belonging to this complex are able to develop three different types of interaction with plant hosts including biotrophic, necrotrophic and hemibiotrophic infections and are also capable of surviving on weeds and non-hosts without causing visible symptoms. They are mainly asexual, but some have a teleomorphic state called Glomerella and can be either homothallic or heterothallic. The sexual behaviour in Glomerella is more complicated than in most ascomycetes, and strains within the same species do not show a typical MAT1-1/2 system. The overall aim of this study was to gain an improved understanding of the relationships between the genetic diversity of global populations, host association patterns, geographic distribution and biological and pathological attributes. A database (CaITSdb) containing more than 800 rRNA sequences deposited in GenBank was created along with key biogeographic information, and the data have been analysed in order to investigate genetic diversity and distribution of sub-populations and their evolutionary relationships. The combined evidence was used to assemble a core collection of 120 isolates that are representative of the diversity in host preference, geographic origin, mating behaviour and molecular genetic variation. A multi-locus sequencing approach (based on four neutral loci) has been used to evaluate phylogenetic relationships amongst the isolates in the core collection. A strong relationship was observed between various genetic groups distinguished and their mating behaviour, geographic distribution and host association patterns. Oceania has been identified as a likely geographic origin of this pathogen, as the highest level of variability and groups related to a hypothetical ancestral population are mainly distributed in these countries. All homothallic isolates capable of producing perithecia belonged to the same genetic group A7; whereas all self-sterile heterothallic isolates were classified as either A3 or A5. Isolates derived from the same host tend to cluster together into genetic groups or sub-populations. This evidence is generally in agreement with recent published work on taxonomic re-assessment of Colletotrichum acutatum sensu lato, which indicates at least fifteen new species. This study has provided the evidence for the occurrence of three distinct genetic groups on strawberry in the UK corresponding to three species reported in the literature namely, C. nymphaeae, C. fioriniae and C. godetiae. Isolates belonging to the genetic groups that correspond to C. nymphaeae and C. fioriniae appeared to be the most aggressive on strawberry, followed by C. godetiae, and C. simmondsii (not found in the UK). Representative isolates of other species were less aggressive. The first whole genome sequence an isolate (A9 = C. simmondsii) from the C. acutatum sensu species complex was assembled and analysed using a range of bioinformatics algorithms. An isolate of C. simmondsii was chosen based on its wide host range including strawberry and the phylogeographic position. Genome analyses enabled prediction and annotation of the whole gene set at 13549 including 6 % unique to this species. The data also suggested an interesting expansion of several gene families, such as those encoding carbohydrate-active enzymes, secondary metabolites pathways and effectors which could be associated with the wide host range. The new knowledge and resources developed with the genome analyses along with the results of the population level diversity studies provide a platform for future comparative and functional genomics investigations to advance this research