Taxonomy and pathology of Togninia (Diaporthales) and its Phaeoacremonium anamorphs.

The genus Togninia (Diaporthales, Togniniaceae) is here monographed along with its Phaeoacremonium (Pm.) anamorphs. Ten species of Togninia and 22 species of Phaeoacremonium are treated. Several new species of Togninia (T.) are described, namely T. argentinensis (anamorph Pm. argentinense), T. austroafricana (anamorph Pm. austroafricanum), T. krajdenii, T. parasitica, T. rubrigena and T. viticola. New species of Phaeoacremonium include Pm. novae-zealandiae (teleomorph T. novae-zealandiae), Pm. iranianum, Pm. sphinctrophorum and Pm. theobromatis. Species can be identified based on their cultural and morphological characters, supported by DNA data derived from partial sequences of the actin and ß-tubulin genes. Phylogenies of the SSU and LSU rRNA genes were used to determine whether Togninia has more affinity with the Calosphaeriales or the Diaporthales. The results confirmed that Togninia had a higher affinity to the Diaporthales than the Calosphaeriales. Examination of type specimens revealed that T. cornicola, T. vasculosa, T. rhododendri, T. minima var. timidula and T. villosa, were not members of Togninia. The new combinations Calosphaeria cornicola, Calosphaeria rhododendri, Calosphaeria transversa, Calosphaeria tumidula, Calosphaeria vasculosa and Jattaea villosa are proposed. Species of Phaeoacremonium are known vascular plant pathogens causing wilting and dieback of woody plants. The most prominent diseases in which they are involved are Petri disease and esca, which occur on grapevines and are caused by a complex of fungi, often including multiple species of Phaeoacremonium. Various Phaeoacremonium species are opportunistic fungi on humans and cause phaeohyphomycosis. The correct and rapid identification of Phaeoacremonium species is important to facilitate the understanding of their involvement in plant as well as human disease. A rapid identification method was developed for the 22 species of Phaeacremonium. It involved the use of 23 species-specific primers, including 20 primers targeting the ß-tubulin gene and three targeting the actin gene. These primers can be used in 14 multiplex reactions. Additionally, a multiple-entry electronic key based on morphological, cultural and ß-tubulin sequence data was developed to facilitate phenotypic and sequence-based species identification of the different Phaeoacremonium species. Separate dichotomous keys are provided for the identification of the Togninia and Phaeoacremonium species. Keys for the identification of Phaeoacremonium-like fungi and the genera related to Togninia are also provided. The mating strategy of several Togninia species was investigated with ascospores obtained from fertile perithecia produced in vitro. Togninia argentinensis and T. novae-zealandiae have homothallic mating systems, whereas T. austroafricana, T. krajdenii, T. minima, T. parasitica, T. rubrigena and T. viticola were heterothallic.

Interactions between Three Fungi Associated with Esca of Grapevine, and Their Secondary Metabolites

The effect of the culture filtrates, crude organic extracts of culture filtrates, metabolites such as scytalone, pullulan and oligosaccharides produced by three fungi associated with esca, Phaeomoniella chlamydospora (Pch), Phaeoacremonium aleophilum (Pal) and Fomitiporia punctata (Fop), on the growth of the fungi themselves, was studied in vitro. At 1:1 dilution, the culture filtrates of Pal and Pch inhibited Fop completely, whereas at 1:2 dilution they only increased Fop growth latency. Fop was not inhibited by crude organic extracts of Pal or Pch. Growth of Pal was slightly stimulated at the lowest concentrations of Pch crude extracts, whereas it was inhibited at the highest concentration. Scytalone (at 1 mg ml-1), pullulan (at 0.2 mg ml-1) and oligosaccharides up to 2.5 kDa (2 mg ml-1) did not affect the radial growth of Fop

Two Naphthalenone Pentakides from Liquid Cultures of «Phaeoacremonium aleophilum», a Fungus Associated with Esca of Grapevine

Several phytotoxic metabolites were extracted from culture filtrates of Phaeoacremonium aleophilum, a fungus associated with the esca of grapevine and related diseases. Two of these metabolites were identified by chemical and spectroscopic methods as scytalone (23.9 mg l-1) and isosclerone (2.4 mg l-1), two naphthalenone pentaketides already known as fungal metabolites. Assayed on detached leaves of grapevine cv. Italia, scytalone at 0.05 mg ml-1 caused light green to chlorotic, rounded to irregular, interveinal or marginal spots, and isosclerone at 0.1 mg ml-1 caused large, coalescent chlorotic and necrotic spots followed by distortion of the lamina and withering. This is the first report on the production in vitro of scytalone and isosclerone by P. aleophilum, and on the phytotoxic activity of these compounds

Infection of Grapevines by Some Fungi Associated with Esca. I. «Fomitiporia punctata» as a Wood-Rot Inducer

Inoculation experiments with three strains of Fomitiporia punctata on grapevine cv. Sangiovese and on grafted ‘Italia’ rootstocks were carried out in southern Italy in 1992-1993. Inoculations were performed on fresh wounds made on the spurs, branches and trunks of vines showing no symptoms of esca. The fungus developed in the discoloured wood around the inoculation site, and caused white rot within two years. No symptoms were induced on foliage or fruit of the infected vines, nor was there any significant difference in virulence of the strains of F. punctata. After 2 years, re-isolation of F. punctata from the diseased woody tissues was successful, whereas no other species of fungi suspected to act as a “precursor” of wood decay were isolated. In 1999, further experiments were carried out with one strain of F. punctata on standing vines cv. Italia and Matilde free of any sign of wood deterioration. The development of internal symptoms was recorded monthly. The results indicated that the cv. Matilde was less susceptible than the cv. Italia. The first signs of spongy wood decay appeared 6 months after inoculation on both cultivars. F. punctata was re-isolated from the infected vines, whereas no species of Phaeoacremonium or other wood-decaying fungi were isolated from either inoculated or non-inoculated vines. These findings suggest that F. punctata behaves as a primary pathogen, being able to cause wood deterioration and spongy decay both on adult and young grapevines in a relatively short time, without the prior or concurrent action of other fungi

Interaction between Esca-Associated Fungi, Grapevine Calli and Micropropagated Shoot Cultures of Grapevine

Callus of the grapevine cv. Italia, micropropagated shoot cultures of the cv. Italia, Matilde and Sangiovese and callus of the tobacco cv. White Burley were cultivated on modified LS and MS-media. Phaeomoniella chlamydospora (Pch), Phaeoacremonium aleophilum (Pal) and Fomitiporia punctata (Fop) grew well in the presence of calli and vitroplants of all the grapevine cultivars which stimulated the growth of the fungi, but growth of the calli and vitroplants was reduced. All three fungi inhibited callus growth more strongly in grapevine than in tobacco. Fop had the greatest inhibitory effect on grapevine callus. Symptom severity also differed between cultivars. All three fungi invaded callus tissue after entirely overgrowing its surface. Hyphae were observed within the callus mass, where several cellular aggregates showed melanin-like deposits, particularly when invaded by Pal. On the foliar lamina of vitroplants symptoms were produced before and after the invasion of the plantlets by each fungus. Symptoms consisted in light green or chlorotic, rounded or irregular spots between the veins or along the leaf margin. The combination Pal vs. vitroplant gave the fastest host-pathogen response. The susceptibility or resistance of calli or vitroplants to escaassociated fungi could be a means to select grapevine for resistance to these fungi

Characterization of the wood mycobiome of Vitis vinifera in a vineyard affected by Esca. Spatial distribution of fungal communities and their putative relation with leaf symptoms

Original ResearchEsca is a disease complex belonging to the grapevine trunk diseases cluster. It comprises five syndromes, three main fungal pathogenic agents and several symptoms, both internal (i.e., affecting woody tissue) and external (e.g., affecting leaves and bunches). The etiology and epidemiology of this disease complex remain, in part, unclear. Some of the points that are still under discussion concern the sudden rise in disease incidence, the simultaneous presence of multiple wood pathogens in affected grapevines, the causal agents and the discontinuity in time of leaf symptoms manifestation. The standard approach to the study of esca has been mostly through culture-dependent studies, yet, leaving many questions unanswered. In this study, we used Illumina R next-generation amplicon sequencing to investigate the mycobiome of grapevines wood in a vineyard with history of esca. We characterized the wood mycobiome composition, investigated the spatial dynamics of the fungal communities in different areas of the stem and in canes, and assessed the putative link between mycobiome and leaf symptoms. An unprecedented diversity of fungi is presented (289 taxa), including five genera reported for the first time in association with grapevines wood (Debaryomyces, Trematosphaeria, Biatriospora, Lopadostoma, and Malassezia) and numerous hitherto unreported species. Esca-associated fungi Phaeomoniella chlamydospora and Fomitiporia sp. dominate the fungal community, and numerous other fungi associated with wood syndromes are also encountered (e.g., Eutypa spp., Inonotus hispidus). The spatial analysis revealed differences in diversity, evenness and taxa abundances, the unique presence of certain fungi in specific areas of the plants, and tissue specificity. Lastly, the mycobiome composition of the woody tissue in proximity to leaves manifesting ‘tiger stripes’ symptoms of esca, as well as in leaf-symptomatic canes, was highly similar to that of plants not exhibiting any leaf symptomatology. This observation supports the current understanding that leaf symptoms are not directly linked with the fungal communities in the wood. This work builds to the understanding of the microbial ecology of the grapevines wood, offering insights and a critical view on the current knowledge of the etiology of escainfo:eu-repo/semantics/publishedVersio

Fungicides and the grapevine wood mycobiome: a case study on Tracheomycotic Ascomycete Phaemoniella chlamydospora reveals potential for two novel control strategies

Original ResearchPhaeomoniella chlamydospora is a tracheomycotic fungus that colonizes the xylem of grapevines (Vitis vinifera L.), causing wood discoloration, brown wood streaking, gummosis, and wood necrosis, which negatively affect the overall health, productivity, and life span of vines. Current control strategies to prevent or cope with P. chlamydospora infections are frequently ineffective. Moreover, it is unclear how fungicides commonly applied in vineyards against downy and powdery mildew agents affect the wood mycobiome, including wood pathogens such as P. chlamydospora. In this study, we used next-generation sequencing to assess the effects of foliar spray of grapevines with inorganic (copper oxychloride and sulfur), synthetic (penconazole and fosetyl-aluminum), and natural (Blad) fungicides currently used against the downy and powdery mildews. The subjects of our investigation were (i) the resident wood mycobiome, (ii) the early colonization by a consortium of fungal wood endophytes (ACEA1), (iii) the wood colonization success of P. chlamydospora, and (iv) the in planta interaction between P. chlamydospora and ACEA1, under greenhouse conditions, in rooted grapevine cuttings of cv. Cabernet Sauvignon. The data obtained suggest that the resident mycobiome is affected by different fungicide treatments. In addition, the early colonization success of the endophytes composing ACEA1 varied in response to fungicides, with relative abundances of some taxa being overrepresented or underrepresented when compared with the control. The wood colonization by P. chlamydospora comported significant changes in the mycobiome composition, and in addition, it was greatly affected by the foliar spray with Blad, which decreased the relative abundance of this pathogen 12-fold (4.9%) when compared with the control (60.7%) and other treatments. The presence of the pathogen also decreased considerably when co-inoculated into the plant with ACEA1, reaching relative abundances between 13.9% and 2.0%, depending on the fungicide treatment applied. This study shows that fungicides sprayed to prevent infections of powdery and downy mildews have an control strategies to fight P. chlamydospora, namely, the foliar spray with Blad and the use of ACEA1. Further studies to confirm these results are requiredinfo:eu-repo/semantics/publishedVersio

Trend of sexually transmitted infections during the Covid-19 age. What was the impact of the pandemic and the social distancing measures?

Covid-19 pandemic has led to social distancing guidelines andresource allocation with subsequent impairment of sexual healthservices. The impact of such measures and the recommendationsregarding changes of sexual behaviour is a matter of debate

Phytotoxins Produced by Fungi Associated with Grapevine Trunk Diseases

Up to 60 species of fungi in the Botryosphaeriaceae family, genera Cadophora, Cryptovalsa, Cylindrocarpon, Diatrype, Diatrypella, Eutypa, Eutypella, Fomitiporella, Fomitiporia, Inocutis, Phaeoacremonium and Phaeomoniella have been isolated from decline-affected grapevines all around the World. The main grapevine trunk diseases of mature vines are Eutypa dieback, the esca complex and cankers caused by the Botryospheriaceae, while in young vines the main diseases are Petri and black foot diseases. To understand the mechanism of these decline-associated diseases and the symptoms associated with them, the toxins produced by the pathogens involved in these diseases were isolated and characterised chemically and biologically. So far the toxins of only a small number of these decline fungi have been studied. This paper presents an overview of the toxins produced by the most serious of these vine wood pathogens: Eutypa lata, Phaeomoniella chlamydospora, Phaeoacremonium aleophilum and some taxa in the Botryosphaeriaceae family, and examines how these toxins produce decline symptoms. The chemical structure of these metabolites and in some cases their vivotoxin nature are also discussed