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

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

Management of Post-Harvest Anthracnose: Current Approaches and Future Perspectives

Anthracnose is a severe disease caused by Colletotrichum spp. on several crop species. Fungal infections can occur both in the field and at the post-harvest stage causing severe lesions on fruits and economic losses. Physical treatments and synthetic fungicides have traditionally been the preferred means to control anthracnose adverse effects; however, the urgent need to decrease the use of toxic chemicals led to the investigation of innovative and sustainable protection techniques. Evidence for the efficacy of biological agents and vegetal derivates has been reported; however, their introduction into actual crop protection strategies requires the solutions of several critical issues. Biotechnology-based approaches have also been explored, revealing the opportunity to develop innovative and safe methods for anthracnose management through genome editing and RNA interference technologies. Nevertheless, besides the number of advantages related to their use, e.g., the putative absence of adverse effects due to their high specificity, a number of aspects remain to be clarified to enable their introduction into Integrated Pest Management (IPM) protocols against Colletotrichum spp. disease

Insights on KP4 Killer Toxin-like Proteins of Fusarium Species in Interspecific Interactions

KP4 killer toxins are secreted proteins that inhibit cell growth and induce cell death in target organisms. In Fusarium graminearum, KP4-like (KP4L) proteins contribute to fungal virulence in wheat seedling rot and are expressed during Fusarium head blight development. However, fungal KP4L proteins are also hypothesized to support fungal antagonism by permeabilizing cell walls of competing fungi to enable penetration of toxic compounds. Here, we report the differential expression patterns of F. graminearum KP4L genes (Fgkp4l-1, -2, -3 and -4) in a competitive interaction, using Trichoderma gamsii as the antagonist. The results from dual cultures indicate that Fgkp4l-3 and Fgkp4l-4 could participate in the recognition at the distance of the antagonist, while all Fgkp4l genes were highly activated in the pathogen during the physical interaction of both fungi. Only Fgkp4l-4 was up-regulated during the interaction with T. gamsii in wheat spikes. This suggests the KP4L proteins could participate in supporting F. graminearum interspecific interactions, even in living plant tissues. The distribution of KP4L orthologous within the genus Fusarium revealed they are more represented in species with broad host-plant range than in host-specific species. Phylogeny inferred provides evidence that KP4L genes evolved through gene duplications, gene loss and sequence diversification in the genus Fusarium

Alternaria species causing pomegranate and citrus fruit rots in Albania

The fungal genus Alternaria is a relevant pathogen for several commodities including citrus and pomegranate fruits. On citrus, it mainly causes brown spots on fruits and leaves, whereas on pomegranate, it mostly causes a fruit heart rot. In the present study the presence of Alternaria rots on citrus and pomegranate fruits cultivated in Albania was assessed. Representative fruits were collected from different regions. Nineteen and thirteen Alternaria spp. isolates were obtained from pomegranate and citrus samples, respectively. The isolates were identified at species and morphotype level. Micro and macroscopic features separated isolates into four morphotypes. BLAST and phylogenetic analysis using the SCAR Marker OPA1-3 confirmed the isolate identity. All 32 isolates proved to be Alternaria alternata and belonged mainly to morphotype alternata, followed by limoniasperae and tenuissima. All Alternaria strains proved to possess the pksI gene of alternariol biosynthesis. Citrus isolates were tested for the presence of genes of the biosynthesis of the phytotoxins ACT and ACR, but none of them proved to possess them. Concluding, Alternaria spp. might represent a treat to pomegranate and citrus production in Albania, and thus effective control means are needed

Study of MDT calibration constants using H8 testbeam data of year 2004

In year 2004 Atlas performed a long campaign of test beam data taking at the H8 Cern beam. Two sectors of the barrel and endcap regions of the Muon Spectrometer were exposed to the beam and large amount of data were collected in well defined and controlled operating conditions. This allowed a careful study on MDT drift properties. A better understanding of the calibration constants, of their definition and determination and of the criteria for their acceptance has been obtained. Systematic effects and time stability of the constants have also been studied

Combined comparative genomics and gene expression analyses provide insights into the terpene synthases inventory in trichoderma

Trichoderma is a fungal genus comprising species used as biocontrol agents in crop plant protection and with high value for industry. The beneficial effects of these species are supported by the secondary metabolites they produce. Terpenoid compounds are key players in the interaction of Trichoderma spp. with the environment and with their fungal and plant hosts; however, most of the terpene synthase (TS) genes involved in their biosynthesis have yet not been characterized. Here, we combined comparative genomics of TSs of 21 strains belonging to 17 Trichoderma spp., and gene expression studies on TSs using T. gamsii T6085 as a model. An overview of the diversity within the TS-gene family and the regulation of TS genes is provided. We identified 15 groups of TSs, and the presence of clade-specific enzymes revealed a variety of terpenoid chemotypes evolved to cover different ecological demands. We propose that functional differentiation of gene family members is the driver for the high number of TS genes found in the genomes of Trichoderma. Expression studies provide a picture in which different TS genes are regulated in many ways, which is a strong indication of different biological functions

Identification and Comparison of Colletotrichum Secreted Effector Candidates Reveal Two Independent Lineages Pathogenic to Soybean

Colletotrichum is one of the most important plant pathogenic genus of fungi due to its scientific and economic impact. A wide range of hosts can be infected by Colletotrichum spp., which causes losses in crops of major importance worldwide, such as soybean. Soybean anthracnose is mainly caused by C. truncatum, but other species have been identified at an increasing rate during the last decade, becoming one of the most important limiting factors to soybean production in several regions. To gain a better understanding of the evolutionary origin of soybean anthracnose, we compared the repertoire of effector candidates of four Colletotrichum species pathogenic to soybean and eight species not pathogenic. Our results show that the four species infecting soybean belong to two lineages and do not share any effector candidates. These results strongly suggest that two Colletotrichum lineages have acquired the capability to infect soybean independently. This study also provides, for each lineage, a set of candidate effectors encoding genes that may have important roles in pathogenicity towards soybean offering a new resource useful for further research on soybean anthracnose management

Genome sequence of the biocontrol agent coniothyrium minitans conio (IMI 134523)

Coniothyrium minitans (synonym, Paraphaeosphaeria minitans) is a highly specific mycoparasite of the wide host range crop pathogen Sclerotinia sclerotiorum. The capability of C. minitans to destroy the sclerotia of S. sclerotiorum has been well recognized and it is available as a widely used biocontrol product Contans WG. We present the draft genome sequence of C. minitans Conio (IMI 134523), which has previously been used in extensive studies that formed part of a registration package of the commercial product. This work provides a distinctive resource for further research into the molecular basis of mycoparasitism to harness the biocontrol potential of C. minitans

Dynamics of SARS-CoV-2 exposure in Malawian infants between February 2020 and May 2021

Background: Very limited information is available on SARS-CoV-2 seroprevalence in infants in sub-Saharan countries. Objective: In this study, we aimed to determine the rate and the temporal evolution of SARS CoV-2 seropositivity in breastfed Malawian infants. Study design: Blood samples (n = 250) from 158 infants, born to HIV-negative women and women living with HIV, collected from February 2020 to May 2021, were first tested using an Anti-IgG/A/M SARS CoV 2 ELISA assay against trimeric spike protein, and then, if positive, confirmed using a second ELISA assay detecting IgG against Receptor Binding Domain. Results: The confirmed prevalence of anti-SARS CoV-2 antibodies was 31.0% (95% CI: 23.7%-38.3%) with no significant difference between HIV-exposed and HIV-unexposed infants (29.3% and 37.1% respectively, P = 0.410). The presence of anti-SARS-CoV-2 IgG was not associated with maternal socioeconomic or demographic indices. Conclusions: Our data underline the wide spread of the SARS-CoV-2 infection in the pediatric population in sub-Saharan Africa. Design of more specific serological tests for African samples and improvements in serosurveillance programs are needed for more rigorous monitoring of the dynamics of SARS-CoV-2 infection in Africa