Molecular Characterization of Ciborinia camelliae Kohn Shows Intraspecific Variability and Suggests Transcontinental Movement of the Pathogen

Ciborinia camelliae Kohn is the causal agent of camellia flower blight. The fungus infects only the flowers of camellias. C. camelliae isolates obtained from symptomatic samples, collected in 13 different localities worldwide, were characterized by Multi-Locus Sequence Typing (MLST) using the following: (i) a nuclear ribosomal DNA internal transcribed spacer; (ii) subunit 2 of β-tubulin (β-TUB II), (iii) elongation factor 1-α (EF1α); and (iv) glycerol-3-phosphate dehydrogenase (GPDH). The variability of the strains was assessed using a universally primed-polymerase chain reaction (UP-PCR) with six universal primers. Gene sequence comparison showed high similarity among all the European strains and highlighted the diversity of the New Zealand and Chinese representative strains. The profiles obtained by UP-PCR confirmed the significant diversity of extra-European strains and identified subgroups within the European population. The presence of shared genetic profiles obtained from strains isolated in different countries (New Zealand and France) suggests the movement of strains from one location to another, which is probably due to the exchange of infected plant material. Moreover, our study shows the overall high intraspecific variability of C. camelliae, which is likely due to the sexual reproduction of the fungus, suggesting the risk of emergence of new pathotypes adapting to novel camellia varieties.

Insect Biodiversity in a Prealpine Suburban Hilly Area in Italy

Human activities and habitat fragmentation are known to greatly influence biodiversity. The aim of this study was to update an entomological checklist of a prealpine area in Italy, and also to evaluate the influence of different habitats and the proximity to cities on the entomological fauna. This study included different areas of a local park in Northern Italy, covering about 4000 ha, and situated at altitudes between 190 and 960 m asl. The surveys were carried out between 2010 and 2013 using different monitoring techniques (pitfall traps, car mounted nets, light traps, direct catches on soil and vegetation, visual sampling, gall collection). Furthermore, to assess the effect of habitat and locality on the composition of epigeic beetles, pitfall traps were set and inspected from April to September. All captured specimens were classified to species level. A total of 409 species were recorded, belonging to 7 orders and 78 families. A total of 76.1% were represented by Coleoptera, 13% Lepidoptera, 9.4% Hymenoptera, followed by other orders. In particular, some species with peculiar characteristics, or whose presence in the area had not been previously reported, were detected, such as Atheta pseudoelongatula, Ocypus rhaeticus, Tasgius tricinctus, Euplagia quadripunctaria, Scotopteryx angularia, Elachista constitella, Parornix bifurca, Oegoconia huemeri, and Lasius (Lasius) alienus. It seems possible that the habitat affected the community more than the locality. The woods showed a reduced biodiversity, and a simplified community structure. The comparison of the same habitats in different localities did not show significant differences.

A Genome Resource for Ciborinia camelliae, the Causal Agent of Camellia Flower Blight

Ciborinia camelliae Kohn is a camellia pathogen belonging to family Sclerotiniaceae, infecting only flowers of camellias. To better understand the virulence mechanism in this species, the draft genome sequence of the Italian strain of C. camelliae was obtained with a hybrid approach, combining Illumina HiSeq paired reads and MinIon Nanopore long-read sequencing. This combination improved significantly the existing National Center for Biotechnology Information reference genome. The assembly contiguity was implemented decreasing the contig number from 2,604 to 49. The N₅₀ contig size increased from 31,803 to 2,726,972 bp and the completeness of assembly increased from 94.5 to 97.3% according to BUSCO analysis. This work is foundational to allow functional analysis of the infection process in this scarcely known floral pathogen. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Real-world costs and dynamics of surveillance in patients who underwent surgery for low-risk branch duct intraductal papillary mucinous neoplasms

Surveillance costs and appropriateness of surgery of "low-risk" BD-IPMNs are relevant issues. In this study we evaluated the rate of correct indication for pancreatectomy defined as high grade dysplasia (HGD) at histology in 961 patients who underwent surveillance for a median of 5.1 years. Undertreatment and overtreatment were defined as invasive cancer and low grade dysplasia (LGD) at histology, respectively. Of the 66 patients (6.9%) who were operated, only 16 (23.8%) had a HGD while 40 (59.7%) had a LGD and 10 (14.9%) an invasive cancer, without differences regarding timing of surgery. The mean surveillance cost was € 194.9 ± 107.6 per patient-year, with a median cost of € 277.1 ± 148.2 in the correct surgery group compared with € 222.7 ± 111.6 and € 197 ± 102.7 in the overtreatment and undertreatment groups. The surveillance mean cost from diagnosis to surgery was € 854.8. Rate of appropriate surgery in BD-IPMNs under surveillance is low.

Challenges in economic evaluation of public health interventions: the example of surveillance of high risk pancreatic tumour patients

Evaluation of public health interventions raises a number of potential challenges in applying and performing economic analyses. The impact of interventions may extend beyond the health sector, and even within the health sector, the value may be difficult to estimate and extended beyond the health improvement of individuals. Screening and surveillance cancer programmes give the possibility to detect patients in a curable and treatable stage. Increasing number of expert recommendations and guidelines of cancer screening and surveillance have been recorded in the last decades. This scenario has increased the uncertainty on the most valuable and affordable approach to adopt. A case study can be provided by the premalignant pancreatic primarily cystic tumours surveillance. American, European and International guidelines for surveillance of asymptomatic cysts are available with significant differences in patients stratification, surveillance intensity (frequency of visits-exams), and duration. Further, real-world data suggest a significant variability in the surveillance approach even within Europe. However, no comparative data on different programmes efficacy are available, neither reliable medium-long term data on cancer risk. The lack of evidence must be considered with methodological issue associated to the inclusion of method to estimate inequalities created by the different programs and the indirect effect of healthcare resources consumption (e.g. CT and MRI) to access and allocation of these resources to other subjects (cancer and no cancer patients). Economic evaluations of surveillance or screening cancer program raise significant challenges, as data availability and methodological approach to apply. This scenario highlight the need of specific recommendation on data quality and type required to assess the programmes value and on methodological approach required (e.g. type of decision analytical models) to provide useful information for public health decision makers.

Exploring Mitogenomes Diversity of Fusarium musae from Banana Fruits and Human Patients

Fusarium musae has recently been described as a cross-kingdom pathogen causing post-harvest disease in bananas and systemic and superficial infection in humans. The taxonomic identity of fungal cross-kingdom pathogens is essential for confirming the identification of the species on distant infected hosts. Understanding the level of variability within the species is essential to decipher the population homogeneity infecting human and plant hosts. In order to verify that F. musae strains isolated from fruits and patients are part of a common population and to estimate their overall diversity, we assembled, annotated and explored the diversity of the mitogenomes of 18 F. musae strains obtained from banana fruits and human patients. The mitogenomes showed a high level of similarity among strains with different hosts’ origins, with sizes ranging from 56,493 to 59,256 bp. All contained 27 tRNA genes and 14 protein-coding genes, rps3 protein, and small and large ribosomal subunits (rns and rnl). Variations in the number of endonucleases were detected. A comparison of mitochondrial endonucleases distribution with a diverse set of Fusarium mitogenomes allowed us to specifically discriminate F. musae from its sister species F. verticillioides and the other Fusarium species. Despite the diversity in F. musae mitochondria, strains from bananas and strains from human patients group together, indirectly confirming F. musae as a cross-kingdom pathogen.

The First Mitochondrial Genome of Ciborinia camelliae and Its Position in the Sclerotiniaceae Family

Ciborinia camelliae is the causal agent of camellia flower blight (CFB). It is a hemibiotrophic pathogen, inoperculate Discomycete of the family Sclerotiniaceae. It shows host and organ specificity infecting only flowers of species belonging to the genus Camellia, causing serious damage to the ornamental component of the plant. In this work, the first mitochondrial genome of Ciborinia camellia is reported. The mitogenome was obtained by combining Illumina short read and Nanopore long read technology. To resolve repetitive elements, specific primers were designed and used for Sanger sequencing. The manually curated mitochondrial DNA (mtDNA) of the Italian strain DSM 112729 is a circular sequence of 114,660 bp, with 29.6% of GC content. It contains two ribosomal RNA genes, 33 transfer RNAs, one RNase P gene, and 62 protein-coding genes. The latter include one gene coding for a ribosomal protein (rps3) and the 14 typical proteins involved in the oxidative metabolism. Moreover, a partial mtDNA assembled from a contig list was obtained from the deposited genome assembly of a New Zealand strain of C. camelliae. The present study contributes to understanding the mitogenome arrangement and the evolution of this phytopathogenic fungus in comparison to other Sclerotiniaceae species and confirms the usefulness of mitochondrial analysis to define phylogenetic positioning of this newly sequenced species.

Telomere to Telomere Genome Assembly of Fusarium musae F31, Causal Agent of Crown Rot Disease of Banana

Fusarium musae causes crown rot of banana and it is also associated to clinical fusariosis. A chromosome-level genome assembly of F. musae F31 obtained combining Nanopore long reads and Illumina paired-end reads resulted in 12 chromosomes plus one contig with overall N₅₀ of 4.36 Mb, and is presented together with its mitochondrial genome (58,072 bp). The F31 genome includes telomeric regions for 11 of the 12 chromosomes representing one of the most complete genomes available in the Fusarium fujikuroi species complex. The high-quality assembly of the F31 genome will be a valuable resource for studying the pathogenic interactions occurring between F. musae and banana. Moreover, it represents an important resource for understanding the genome evolution in the F. fujikuroi species complex.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Biological risk assessment in the History and Historical Documentation Library of the University of Milan

There are billions of books that in recent and in ancient times have been produced by the human race containing evidence of its intellectual and cultural efforts. Even when stored in libraries, not all these books survive over time undamaged, because in the biosphere their materials are potential nutrients. This is the unfortunate case of the History and Historical Documentation Library of the University of Milan, where biological agents have badly affected rare and valuable old books. An entomological monitoring was carried out using sticky traps and collecting insects during inspections. The beetle Gastrallus pubens Fairmaire, rarely identified in European libraries so far, was the main biological agent responsible for the book damage, since several tunnels due to larval activity and holes made by adults were observed. Using the Illumina MiSeq sequencing technology, Proteobacteria, Firmicutes and Actinobacteria were found to be the most abundant phyla. Ascomycota was the dominant phylum among three fungal phyla. As bacteria and fungi spread by the insects are primary indications of the insect presence in the library, in this paper a potential biomarker able to detect the G. pubens presence before visible infestation was searched for among the bacterial and fungal community peculiar in the insect frass and gut, but also found on books and the surfaces of shelves. Symbiotaphrina, an ascomycete fungus described as one of the symbiotic levuliform fungi, present in the anobiid beetles' gut, was the only one found in all samples analyzed and has therefore been proposed as a putative biomarker.

Fusarium musae from Diseased Bananas and Human Patients: Susceptibility to Fungicides Used in Clinical and Agricultural Settings

Fusarium musae belongs to the Fusarium fujikuroi species complex. It causes crown rot disease in banana but also keratitis and skin infections as well as systemic infections in immunocompromised patients. Antifungal treatments in clinical and agricultural settings rely mostly on molecules belonging to the azole class. Given the potential risk of pathogen spread from food to clinical settings, the goal of the work was to define the level of susceptibility to different azoles of a worldwide population of F. musae. Eight fungicides used in agriculture and five antifungals used in clinical settings (4 azoles and amphotericin B) were tested using the CLSI (Clinical and Laboratory Standards Institute) protocol methodology on 19 F. musae strains collected from both infected patients and bananas. The level of susceptibility to the different active molecules was not dependent on the source of isolation with the exception of fenbuconazole and difenoconazole which had a higher efficiency on banana-isolated strains. Minimal inhibitory concentrations (MICs) of the different molecules ranged from 0.12–0.25 mg/L for prochloraz to more than 16 mg/L for tetraconazole and fenbuconazole. Compared to the F. verticillioides, F. musae MICs were higher suggesting the importance of monitoring the potential future spread of this species also in clinical settings.

2020 position statement and recommendations of the European Liver and Intestine Transplantation Association (ELITA): management of hepatitis B virus-related infection before and after liver transplantation

BACKGROUND

Prophylaxis of HBV recurrence is critical after liver transplantation in HBV patients. Despite new prophylactic schemes, most European LT centres persist on a conservative approach combining hepatitis B immunoglobulin (HBIG) and nucleos(t)ides analogues (NA).

AIM

This setting prompted the European Liver Intestine Transplantation Association (ELITA) to look for a consensus on the prevention of HBV recurrence.

METHODS

Based on a 4-round Delphi process, ELITA investigated 16 research questions and established 50 recommendations.

RESULTS

Prophylaxis should be driven according to 3 simplified risk groups: Low and high virological risk patients, with undetectable and detectable HBV DNA pre-LT, respectively, and special populations (HDV, HCC, poorly adherent patients). In low-risk patients, short-term (4 weeks) combination of third-generation NA+ HBIG, or third generation NA monotherapy can be considered as prophylactic options. In high-risk patients, HBIG can be discontinued once HBV DNA undetectable. Combined therapy for 1 year is advised. HBV-HCC patients should be treated according to their virological risk. In HDV/HBV patients, indefinite dual prophylaxis remains the gold standard. Full withdrawal of HBV prophylaxis following or not HBV vaccination should only be attempted in the setting of clinical trials. Organs from HBsAg+ve donors may be considered after assessment of risks, benefits, and patient consent. They should not be used if HDV is present. In poorly adherent patients, dual long-term prophylaxis is recommended. Budget impact analysis should be taken into account to drive prophylactic regimen.

CONCLUSIONS

These ELITA recommendations should stimulate a more rational and homogeneous approach to HBV prophylaxis across LT programs.

Grapevine Powdery Mildew: Fungicides for Its Management and Advances in Molecular Detection of Markers Associated with Resistance

Grapevine powdery mildew is a principal fungal disease of grapevine worldwide. Even though it usually does not cause plant death directly, heavy infections can lead to extensive yield losses, and even low levels of the disease can negatively affect the quality of the wine. Therefore, intensive spraying programs are commonly applied to control the disease, which often leads to the emergence and spread of powdery mildew strains resistant to different fungicides. In this review, we describe major fungicide classes used for grapevine powdery mildew management and the most common single nucleotide mutations in target genes known to confer resistance to different classes of fungicides. We searched the current literature to review the development of novel molecular methods for quick detection and monitoring of resistance to commonly used single-site fungicides against Erysiphe necator. We analyze and compare the developed methods. From our investigation it became evident that this research topic has been strongly neglected and we hope that effective molecular methods will be developed also for resistance monitoring in biotroph pathogens.

Draft genome sequences of two Streptomyces albidoflavus strains DEF1AK and DEF147AK with plant growth-promoting and biocontrol potential

Purpose

Bacteria belonging to the Streptomyces genus can be exploited in environmentally friendly approaches to food safety. Genome information can help to characterize bioactive strains opening the possibility to decipher their mechanisms of action.

Methods

The biocontrol and plant growth-promoting activity of two Streptomyces spp. strains, DEF1AK and DEF147AK, were assessed in vitro and in planta. The genome sequences were determined using the Illumina NextSeq sequencing system and were assembled using EvoCAT (Evogene Clustering and Assembly Toolbox).

Result

Streptomyces spp. DEF1AK and DEF147AK were able to improve seed germination and early plant development of maize, wheat, and tomato and inhibited the mycelium growth of diverse fungal plant pathogens in vitro. The genome sequence analysis identified both strains as S. albidoflavus (99% sequence identity). Both genomes were of 7.1-Mb length with an average GC content of 73.45%. AntiSMASH and MIBiG analyses revealed strain-specific sets of secondary metabolite gene clusters in the two strains as well as differences in the number and type of duplicated genes.

Conclusion

The combination of the biological activity and genomic data is the basis for in-depth studies aimed at the identification of secondary metabolites involved in plant growth-promoting and biocontrol activity of Streptomyces spp. The comparison of unique genomic features of the two strains will help to explain their diverse biocontrol and plant growth-promoting activities and warrant targeted functional genomics approaches to verify their mechanisms of action.

Selection of an Endophytic Streptomyces sp. Strain DEF09 From Wheat Roots as a Biocontrol Agent Against Fusarium graminearum

Selection of biological control agents (BCA) profits from an integrated study of the tripartite interactions occurring among the BCA, the plant and the pathogen. The environment plays a crucial role in the efficacy of BCA, therefore, the selection process shall utmost mimic naturally occurring conditions. To identify effective biocontrol strains against Fusarium graminearum, the major cause of Fusarium head blight (FHB) in wheat and deoxynivalenol (DON) accumulation in grains, a workflow consisting of in vitro and in vivo assays was set up. Twenty-one Streptomyces strains, 16 of which were endophytes of different plants, were analyzed. In vitro and in vivo tests characterized their plant growth promoting (PGP) traits. Biocontrol activity against F. graminearum was firstly assessed with a dual culture assay. An in vivo germination blotter assay measured Fusarium foot rot and root rot symptoms (FFR-FRR) reduction as well as growth parameters of the plant treated with the Streptomyces strains. A selected subset of Streptomyces spp. strains was then assessed in a growth chamber measuring FFR symptoms and growth parameters of the wheat plant. The approach led to the identification of an effective Streptomyces sp. strain, DEF09, able to inhibit FHB on wheat in controlled conditions by blocking the spread of the pathogen at the infection site. The results were further confirmed in field conditions on both bread and durum wheat, where DEF09 decreased disease severity up to 60%. This work confirms that FRR and FFR pathosystems can be used to identify BCA effective against FHB.

Dual-active antifungal agents containing strobilurin and SDHI-based pharmacophores

Crop disease management often implies repeated application of fungicides. However, the increasing emergence of fungicide-resistant pathogens requires their rotation or combined use. Tank-mix combinations using fungicides with different modes of action are often hard to manage by farmers. An alternative and unexploited strategy are bifunctional fungicides, i.e. compounds resulting from conjugation of the pharmacophores of fungicides with different mechanisms of action. In this paper we describe a new approach to antifungal treatments based on the synthesis of dual agents, obtained by merging the strobilurin and succinate dehydrogenase inhibitor pharmacophores into a new entity. The compounds were tested against important fungal plant pathogens and showed good inhibition of Pyricularia oryzae and Sclerotinia sclerotiorum with activity comparable to commercial fungicides. The inhibition of the cytochrome bc1 and the succinate dehydrogenase enzyme activity confirmed that the new molecules are endowed with a dual mechanism of action. These results were further supported by molecular modelling which showed that selected compounds form stable complexes with both cytochrome b subunit and succinate dehydrogenase enzyme. This work can be considered an important first step towards the development of novel dual-action agents with optimized structure and improved interaction with the targets.

Evaluation of in-vitro methods to select effective streptomycetes against toxigenic fusaria

Biocontrol microorganisms are emerging as an effective alternative to pesticides. Ideally, biocontrol agents (BCAs) for the control of fungal plant pathogens should be selected by an in vitro method that is high-throughput and is predictive of in planta efficacy, possibly considering environmental factors, and the natural diversity of the pathogen. The purpose of our study was (1) to assess the effects of Fusarium strain diversity (N = 5) and culture media (N = 6) on the identification of biological control activity of Streptomyces strains (N = 20) against Fusarium pathogens of wheat in vitro and (2) to verify the ability of our in vitro screening methods to simulate the activity in planta. Our results indicate that culture media, Fusarium strain diversity, and their interactions affect the results of an in vitro selection by dual culture assay. The results obtained on the wheat-based culture media resulted in the highest correlation score (r = 0.5) with the in planta root rot (RR) inhibition, suggesting that this in vitro method was the best predictor of in planta performance of streptomycetes against Fusarium RR of wheat assessed as extension of the necrosis on the root. Contrarily, none of the in vitro plate assays using the media tested could appropriately predict the activity of the streptomycetes against Fusarium foot rot symptoms estimated as the necrosis at the crown level. Considering overall data of correlation, the activity in planta cannot be effectively predicted by dual culture plate studies, therefore improved in vitro methods are needed to better mimic the activity of biocontrol strains in natural conditions. This work contributes to setting up laboratory standards for preliminary screening assays of Streptomyces BCAs against fungal pathogens.

Fungal Biofilms: Targets for the Development of Novel Strategies in Plant Disease Management

The global food supply has been facing increasing challenges during the first decades of the 21st century. Disease in plants is an important constraint to worldwide crop production, accounting for 20-40% of its annual harvest loss. Although the use of resistant varieties, good water management and agronomic practices are valid management tools in counteracting plant diseases, there are still many pathosystems where fungicides are widely used for disease management. However, restrictive regulations and increasing concern regarding the risk to human health and the environment, along with the incidence of fungicide resistance, have discouraged their use and have prompted for a search for new efficient, ecologically friendly and sustainable disease management strategies. The recent evidence of biofilm formation by fungal phytopathogens provides the scientific framework for designing and adapting methods and concepts developed by biofilm research that could be integrated in IPM practices. In this perspective paper, we provide evidence to support the view that the biofilm lifestyle plays a critical role in the pathogenesis of plant diseases. We describe the main factors limiting the durability of single-site fungicides, and we assemble the current knowledge on pesticide resistance in the specific context of the biofilm lifestyle. Finally, we illustrate the potential of antibiofilm compounds at sub-lethal concentrations for the development of an innovative, eco-sustainable strategy to counteract phytopathogenic fungi. Such fungicide-free solutions will be instrumental in reducing disease severity, and will permit more prudent use of fungicides decreasing thus the selection of resistant forms and safeguarding the environment.

Feasibility, acceptability and construct validity of EQ-5D in systemic sclerosis

BACKGROUND

Systemic sclerosis is a chronic disabling disease that is often associated with severe physical and psychological impairment. Nonetheless, health-related quality of life (HRQoL) in patients with systemic sclerosis is often left behind in clinical practice and research. One of the reasons for this lack of evaluation is the current use of tools, such as the short form-36 (SF-36) questionnaire, that are complete but complicated to use in everyday routine. Other self-reported outcome measures such as the health assessment questionnaire (HAQ) are simple, but specifically designed for physical disability.

STUDY AIMS AND METHODS

Our aim was to evaluate the feasibility, acceptability and construct validity of EQ-5D, a simple and quick self-assessment tool, and to compare its performance with SF-36 and HAQ. We investigated 119 consecutive patients with systemic sclerosis (94% female; age: median 63 years, interquartile range 53-70 years) at three different rheumatology centres. Acceptability was evaluated from comments made by the patients and feasibility on the basis of the number of patients needing assistance or not answering questions (missing data). Construct validity was based on both convergent and divergent validity between conceptually similar and dissimilar domains, respectively, of the compared instruments.

RESULTS

EQ-5D was well accepted by patients. The percentage of patients missing data in at least one EQ-5D domain was 2.5%. Spearman's correlation coefficients between similar dimensions of EQ-5D vs SF-36 and vs HAQ were moderate (≥0.30) to strong (≥0.50); in contrast, correlation coefficients between less comparable dimensions were weak. As expected, the EQ-5D anxiety/depression domain did not correlate with any of the HAQ domains. The EQ-5D visual analogue scale (VAS) concordance with SF-36 general health domain and HAQ total score was strong (≥0.50 for both). Median value for the EQ-5D index (interquartile range) was 0.81 (0.75-0.86). The EQ-5D index had correlation coefficients >0.40 with all SF-36 domains and with all HAQ domains, HAQ total and HAQ VAS.

CONCLUSIONS

Our data demonstrate good acceptability, feasibility and construct validity of EQ-5D in patients with systemic sclerosis. We suggest the use of EQ-5D in systemic sclerosis patients as an HRQoL measure in clinical practice, in randomised clinical trials and/or in pharmacoeconomic evaluations.

Selection of Streptomyces against soil borne fungal pathogens by a standardized dual culture assay and evaluation of their effects on seed germination and plant growth

Background

In the search for new natural resources for crop protection, streptomycetes are gaining interest in agriculture as plant growth promoting bacteria and/or biological control agents. Because of their peculiar life cycle, in which the production of secondary metabolites is synchronized with the development of aerial hyphae and sporulation, the commonly used methods to screen for bacterial antagonists need to be adapted.

Results

The dual culture assay was standardized in terms of inoculation timing of Streptomyces antagonist and pathogen, and growth rate of different fungal pathogens. In case of fast-growing fungi, inoculation of the antagonist 2 or 3 days prior to the pathogen resulted in significantly stronger inhibition of mycelium growth. One hundred and thirty Streptomyces strains were evaluated against six destructive soil borne pathogens. The activity of strains varied from broad-spectrum to highly specific inhibition of individual pathogens. All strains inhibited at least one tested pathogen. Three strains, which combined the largest broad-spectrum with the highest inhibition activity, were selected for further characterization with four vegetable species. All of them were able to colonize seed surface of all tested vegetable crops. They mostly improved radicle and hypocotyl growth in vitro, although no statistically significant enhancement of biomass weight was observed in vivo. Occasionally, transient negative effects on germination and plant growth were observed.

Conclusions

The adapted dual culture assay allowed us to compare the inhibition of individual Streptomyces strains against six fungal soil borne pathogens. The best selected strains were able to colonize the four vegetable crops and have a potential to be developed into biocontrol products. Although they occasionally negatively influenced plant growth, these effects did not persist during the further development. Additional in vivo studies are needed to confirm their potential as biological control or plant growth promoting agents.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-016-0886-1) contains supplementary material, which is available to authorized users.

New formulation and delivery method of Cryphonectria parasitica for biological control of chestnut blight

AIMS

This study aimed to develop a new formulation of Cryphonectria parasitica hypovirulent mycelium suitable for inoculations of tall trees from the ground. Cryphonectria parasitica hypovirulent strains are widely used for biological control of chestnut blight. However, it is often inconsistent and ineffective not only for biological reasons but also because the current manual application of hypovirulent strains on adult plants is difficult, time-consuming and expensive. Here, we propose an improved formulation and more effective mode of application of hypovirulent strains, which could boost chestnut blight biocontrol.

METHODS AND RESULTS

The Cp 4.2H hypovirulent strain was formulated as mycelium discs with polyethylene glycol and hydroxypropyl methylcellulose, loaded into lead-free pellets that are used as carriers to inoculate cankers on chestnut stems by shooting. The formulation of mycelium did not hamper its viability which was stable, with an estimated shelf life of 72 days at 6 ± 1°C. The inoculum effectiveness was confirmed ex planta and in planta in a small-scale pilot study in field, where formulated mycelium discs of hypovirulent strain Cp 4.2H were inoculated by airgun shot method into the chestnut bark. In planta, Cp 4.2H was recovered in 37% of bark samples taken around the inoculated points 1 year after the treatment.

CONCLUSIONS

We demonstrated that the proposed airgun shooting inoculation method of C. parasitica hypovirulent strain formulated as mycelium discs is suitable for treatment of adult chestnut trees.

SIGNIFICANCE AND IMPACT OF THE STUDY

The proposed method could be a valid alternative to the traditional manual technique of chestnut biocontrol. The main advantages are the cost-effectiveness and the ease to treat high-positioned, otherwise unreachable cankers both in orchards and forests.

Biological Control of Lettuce Drop and Host Plant Colonization by Rhizospheric and Endophytic Streptomycetes

Lettuce drop, caused by the soil borne pathogen Sclerotinia sclerotiorum, is one of the most common and serious diseases of lettuce worldwide. Increased concerns about the side effects of chemical pesticides have resulted in greater interest in developing biocontrol strategies against S. sclerotiorum. However, relatively little is known about the mechanisms of Streptomyces spp. as biological control agents against S. sclerotiorum on lettuce. Two Streptomyces isolates, S. exfoliatus FT05W and S. cyaneus ZEA17I, inhibit mycelial growth of Sclerotinia sclerotiorum by more than 75% in vitro. We evaluated their biocontrol activity against S. sclerotiorum in vivo, and compared them to Streptomyces lydicus WYEC 108, isolated from Actinovate®. When Streptomyces spp. (10(6) CFU/mL) were applied to S. sclerotiorum inoculated substrate in a growth chamber 1 week prior lettuce sowing, they significantly reduced the risk of lettuce drop disease, compared to the inoculated control. Interestingly, under field conditions, S. exfoliatus FT05W and S. cyaneus ZEA17I protected lettuce from drop by 40 and 10% respectively, whereas S. lydicus WYEC 108 did not show any protection. We further labeled S. exfoliatus FT05W and S. cyaneus ZEA17I with the enhanced GFP (EGFP) marker to investigate their rhizosphere competence and ability to colonize lettuce roots using confocal laser scanning microscopy (CLSM). The abundant colonization of young lettuce seedlings by both strains demonstrated Streptomyces' capability to interact with the host from early stages of seed germination and root development. Moreover, the two strains were detected also on 2-week-old roots, indicating their potential of long-term interactions with lettuce. Additionally, scanning electron microscopy (SEM) observations showed EGFP-S. exfoliatus FT05W endophytic colonization of lettuce root cortex tissues. Finally, we determined its viability and persistence in the rhizosphere and endorhiza up to 3 weeks by quantifying its concentration in these compartments. Based on these results we conclude that S. exfoliatus FT05W has high potential to be exploited in agriculture for managing soil borne diseases barely controlled by available plant protection products.

Metrafenone resistance in a population of Erysiphe necator in northern Italy

BACKGROUND

Metrafenone has been used in Europe in integrated pest management programmes since 2006 to control powdery mildews, including Erysiphe necator. Its exact mode of action is not known, but it is unique among fungicide classes used in powdery mildew management. Recently, resistance to metrafenone was reported in Blumeria graminis f. sp. tritici. In this study we investigated metrafenone resistance in Erysiphe necator in northern Italy.

RESULTS

Metrafenone efficacy to control grapevine powdery mildew was monitored in three consecutive years in the field, and its reduced activity was observed in 2013. Out of 13 monoconidial isolates, two sensitive strains were identified, which did not grow at the fungicide concentration recommended for field application. The remaining strains showed variable response to metrafenone, and five of them grew and sporulated similarly to the control, even at 1250 mg L(-1) of metrafenone. Moreover, the resistant strains showed cross-resistance to pyriofenone, which belongs to the same FRAC group as metrafenone.

CONCLUSION

The results indicate the emergence of metrafenone resistance in an Italian population of Erysiphe necator. Further studies are needed to gain insight into the metrafenone's mode of action and to understand the impact of resistance on changes in the pathogen population structure, fitness and spread of resistant strains, which will be indicative for designing appropriate antiresistance measures.

Colonization of lettuce rhizosphere and roots by tagged Streptomyces

Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots, and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic.

Sensitivity of Nonexposed and Exposed Populations of Magnaporthe oryzae from Rice to Tricyclazole and Azoxystrobin

Magnaporthe oryzae is the major pathogen of cultivated rice worldwide, which can cause substantial losses to rice production. Rice blast management is based predominantly on the application of fungicides; however, only a little is known about responses of pathogen populations to the most widely used fungicides. In this work, the baseline sensitivity of the Italian M. oryzae population to tricyclazole and azoxystrobin in terms of mycelium growth was determined, and the possible adaptation of the pathogen population after several years of repeated exposure to fungicide treatments was evaluated. All the analyzed strains demonstrated higher sensitivity and variability to azoxystrobin (concentration of fungicide causing 50% growth inhibition [ED₅₀] = 0.063 mg liter^-1) than to tricyclazole (99.289 mg liter^-1). After comparing two additional populations collected from fields repeatedly treated with fungicides to the baseline, no decrease in sensitivity toward these fungicides was observed and no resistant strains were detected. The shift of the pathogen sensitivity toward these fungicides has not occurred, although we observed slightly increased variance associated with ED₅₀ of azoxystrobin. Therefore, both azoxystrobin and tricyclazole can be used to manage rice blast in Italy but it will be important to continue monitoring M. oryzae population to early detect possible azoxystrobin resistance.

Impact of tricyclazole and azoxystrobin on growth, sporulation and secondary infection of the rice blast fungus, Magnaporthe oryzae

BACKGROUND

Rice blast, caused by Magnaporthe oryzae B. Couch sp. nov., is one of the most destructive rice diseases worldwide, causing substantial yield losses every year. In Italy, its management is based mainly on the use of two fungicides, azoxystrobin and tricyclazole, that restrain the disease progress. The aim of this study was to investigate and compare the inhibitory effects of the two fungicides on the growth, sporulation and secondary infection of M. oryzae.

RESULTS

Magnaporthe oryzae mycelium growth was inhibited at low concentrations of azoxystrobin and relatively high concentrations of tricyclazole, while sporulation was more sensitive to both fungicides and was affected at similarly low doses. Furthermore, infection efficiency of conidia obtained from mycelia exposed to tricyclazole was affected to a higher extent than for conidia produced on azoxystrobin-amended media, even though germination of such conidia was reduced after azoxystrobin treatment.

CONCLUSIONS

This study presents for the first time detailed azoxystrobin and tricyclazole growth-response curves for M. oryzae mycelium growth and sporulation. Furthermore, high efficacy of tricyclazole towards inhibition of sporulation and secondary infection indicates an additional possible mode of action of this fungicide that is different from inhibition of melanin biosynthesis.

Anti-inhibitor coagulant complex prophylaxis in hemophilia with inhibitors

BACKGROUND

Patients with severe hemophilia A and factor VIII inhibitors are at increased risk for serious bleeding complications and progression to end-stage joint disease. Effective strategies to prevent bleeding in such patients have not yet been established.

METHODS

We enrolled patients with hemophilia A who were older than 2 years of age, had high-titer inhibitors, and used concentrates known as bypassing agents for bleeding in a prospective, randomized, crossover study comparing 6 months of anti-inhibitor coagulant complex (AICC), infused prophylactically at a target dose of 85 U per kilogram of body weight (±15%) on 3 nonconsecutive days per week, with 6 months of on-demand therapy (AICC at a target dose of 85 U per kilogram [±15%] used for bleeding episodes). The two treatment periods were separated by a 3-month washout period, during which patients received on-demand therapy for bleeding. The primary outcome was the number of bleeding episodes during each 6-month treatment period.

RESULTS

Thirty-four patients underwent randomization; 26 patients completed both treatment periods and could be evaluated per protocol for the efficacy analysis. As compared with on-demand therapy, prophylaxis was associated with a 62% reduction in all bleeding episodes (P<0.001), a 61% reduction in hemarthroses (P<0.001), and a 72% reduction in target-joint bleeding (≥3 hemarthroses in a single joint during a 6-month treatment period) (P<0.001). Thirty-three randomly assigned patients received at least one infusion of the study drug and were evaluated for safety. One patient had an allergic reaction to the study drug.

CONCLUSIONS

AICC prophylaxis at the dosage evaluated significantly and safely decreased the frequency of joint and other bleeding events in patients with severe hemophilia A and factor VIII inhibitors. (Funded by Baxter BioScience; Pro-FEIBA ClinicalTrials.gov number, NCT00221195.).

[Health related quality of life assessment in patients with systemic sclerosis]

OBJECTIVE

Health-related quality of life (HRQoL) in patients with systemic sclerosis (SSc), a chronic disabling disease associated to physical and psychological impairment, is often left behind in clinical practice and research. This is due to the use of tools that are not complete or mainly designed for the physical condition only. We tested EQ-5D, a valid, simple and brief questionnaire for HRQoL that has never been validated in SSc.

METHODS

Thirty-three consecutive SSc patients referring to our Rheumatology Department and undergoing treatment have been asked to fulfill EQ-5D together with HAQ.

RESULTS

EQ-5D demonstrated good acceptability, feasibility and validity in patients affected by SSc. Conceptually equivalent domains of EQ-5D demonstrated a good correlation with HAQ correspondent domains.

CONCLUSIONS

We suggest the use of EQ-5D in SSc patients as a HRQoL measure in clinical practice, as well as an out come parameter in randomized clinical trials and/or in pharmaco-economic evaluations.

Clonal population structure of the chestnut blight fungus in expanding ranges in southeastern Europe

Expanding populations are often less genetically diverse at their margins than at the centre of a species' range. Established, older populations of the chestnut blight fungus, Cryphonectria parasitica, are more variable for vegetative compatibility (vc) types than in expanding populations in southeastern Europe where C. parasitica has colonized relatively recently. To test whether vc types represent clones, we genotyped 373 isolates of C. parasitica from southern Italy, Romania, Bulgaria, Macedonia, Greece and Turkey using 11 sequence-characterized amplified region (SCAR) markers. Ten SCAR loci and six vegetative incompatibility (vic) loci were polymorphic in these samples. These populations are clonal by all criteria tested: (i) among 373 isolates, we found only eight multilocus haplotypes, and the same haplotypes were found in multiple countries, sometimes separated in time by as much as 12 years; (ii) the number of haplotypes observed was significantly less than expected under random mating; (iii) populations are in linkage disequilibrium; (iv) the two sets of independent markers, SCARs and vc types, are highly correlated; and (v) sexual structures of C. parasitica were found only in Bulgaria and Romania. One mating type (MAT-1) was found in 98% of the isolates sampled. In contrast, a population in northern Italy, in the central part of the range in Europe, had 12 multilocus haplotypes among 19 isolates. The spread of a few clones could be the result either of founder effect and restricted migration, or these clones have greater fitness than others and spread because they are better adapted to conditions in southeastern Europe.

Chloramphenicol influence on antioxidant enzymes with preliminary approach on microsomal CYP1A immunopositive-protein in Chamelea gallina

Chloramphenicol (CA) is a largely used antibiotic and it is an inhibitor of protein synthesis that also induces ROS production. In this work there were investigated activities and expressions in the Adriatic bivalve Chamelea gallina of some antioxidant and detoxification proteins like superoxide dismutase (Mn-SOD, Cu/Zn-SOD), catalase (CAT) and Cytochrome P450 (CYP1A). Clams exposed to 5mgl(-1) of chloramphenicol were sampled 2, 4 and 8 days after treatment (CA2, CA4 and CA8). SODs, CAT, and CYP1A activity and/or expression were detected in pooled digestive glands by Western blotting and by spectrophotometrical analysis. Enzymes activities increase during the entire antibiotic exposure. With respect to the control Cu/Zn-SOD expression increases, while Mn-SOD expression decreases significantly after 4 days. Two CYP1A immunopositive-proteins (57.7 and 59.8kDa) were detected. The lower band significantly decreases in CA8, the upper one also in CA4 condition. High levels of Mn-SOD, CAT activity and Cu/Zn-SOD expression, indicate intense ROS production while Mn-SOD expression inhibition might be ascribable to mitochondrial alterations due to CA and indirectly to ROS. CYP1A1 action determines H2O2 production that would contribute to a CYP1A1 gene promoter down regulation, a response to oxidative stress with the antioxidant enzymes activation as a final result. This study highlights the close association, in C. gallina, in presence of chloramphenicol, between SOD/CAT and CYP system, and it appear particularly interesting to the lack of similar researches on mollusc species.

Optimisation of therapeutic strategies for ST-segment elevation acute myocardial infarction: the impact of a territorial network on reperfusion therapy and mortality

OBJECTIVE

To assess the clinical impact of a regional network for the treatment of ST-segment elevation myocardial infarction (STEMI).

METHODS

All patients with STEMI (n = 1823) admitted to any of the hospitals of an area with one million inhabitants during the year 2002 (n = 858)-that is, before the network was implemented, and in 2004 (n = 965), the year of full implementation of the network, were enrolled in this study. The primary evaluation was in-hospital mortality. Secondary outcomes included the incidence of major adverse cardiac and cerebrovascular events (MACCE), defined as death, myocardial infarction, stroke and coronary revascularisation procedures over 1-year follow-up.

RESULTS

Between 2002 and 2004, there was a major change in reperfusion strategy: primary angioplasty increased from 20.2% to 65.6% (p<0.001), fibrinolytic therapy decreased from 38.2% to 10.7% (p<0.001) and the rate of patients not undergoing reperfusion was reduced from 41.6% to 23.7% (p<0.001). In-hospital mortality decreased from 17.0% to 12.3% (p = 0.005), and this reduction was sustained at 1-year follow-up (23.9% in 2002 and 18.8% in 2004, p = 0.009). Similarly, the 1-year incidence of all MACCE was reduced from 39.5% in 2002 to 34.3% in 2004 (p = 0.01).

CONCLUSIONS

Organisation of a territorial network for STEMI is associated with increased rates of reperfusion therapy and reduction of in-hospital and 1-year mortality.

Persistence and spatial autocorrelation of clones of Erysiphe necator overwintering as mycelium in dormant buds in an isolated vineyard in northern Italy

The population structure of the grape powdery mildew fungus, Erysiphe necator (formerly Uncinula necator), has been hypothesized to vary from being clonal to highly diverse and recombining. We report here on the structure of an E. necator population sampled during a 4-year period from an isolated vineyard in northern Italy (Voghera, Pavia Province). We obtained 54 isolates of E. necator that overwintered asexually as mycelium in grapevine buds and caused severe symptoms on the emerging shoots, known as flag shoots. All isolates were genotyped for mating type, four multilocus polymerase chain reaction (PCR)-based markers (a total of 64 loci were scored), and two single-copy loci designed to identify genetic subgroups in E. necator. All isolates had the same mating type and single-locus alleles that correlate to isolates from flag shoots in other areas. Only 2 of the 64 loci scored from multilocus markers were polymorphic; 46 of the 54 isolates had the same multilocus haplotype. Seven isolates had a second haplotype that was recovered over 3 years, and only a single isolate was found with a third haplotype. Both variant haplotypes differed from the main clonal haplotype by single loci. Spatial autocorrelation analyses showed that vines with flag shoots were not aggregated within years, but they were aggregated between consecutive years. These results demonstrate that this subpopulation of E. necator on flag shoots is composed of a single clonal lineage that has persisted for at least 4 years. We speculate that the lack of diversity in the flag shoot subpopulation in this vineyard is the result of restricted immigration from surrounding areas and genetic drift operating through founder effects and periodic bottlenecks. We propose a model that integrates epidemiology and population genetics to explain the variation observed in genetic structure of E. necator flag shoot subpopulations from different vineyards or viticultural regions.

Genetic similarity of flag shoot and ascospore subpopulations of Erysiphe necator in Italy

The overwintering mode of the grape powdery mildew fungus, Erysiphe necator (syn. Uncinula necator), as mycelium in dormant buds (resulting in symptoms known as flag shoots) or as ascospores in cleistothecia, affects the temporal dynamics of epidemics early in the growing season. We tested whether distinct genetic groups (I and III) identified previously in E. necator correlate to overwintering modes in two vineyards in Tuscany, Italy, to determine whether diagnostic genetic markers could be used to predict overwintering. Samples from one vineyard were collected from flag shoots; the other vineyard, 60 km away, had no flag shoots, and mildew colonies were assumed to be derived from ascospores. Genetic markers putatively diagnostic for groups I and III showed that both types were common in the flag shoot subpopulation. Both genetic types were found in the ascospore population, although group III was dominant. We did not find strong genetic differentiation between the two subpopulations based on inter-simple sequence repeat markers. Although there was significant (P < 0.001) genetic differentiation between these subpopulations in 1997 and when 1997 and 1998 subpopulations were pooled (theta = 0.214 and 0.150, respectively), no differentiation was evident between vineyards in 1998 (theta = 0.138, P = 0.872). Moreover, we did not observe distinct lineages corresponding to overwintering modes, as observed in previous studies. We could not determine if differentiation resulted from biological differences or restricted gene flow between the two vineyards. Our samples were taken from both subpopulations early in the epidemic, while previous studies confounded overwintering mode and sampling time. These results do not support a strong correlation between overwintering and genetic groups, highlighting the need to base population biology studies on sound biological and epidemiological knowledge.

Mixed mating in natural populations of the chestnut blight fungus, Cryphonectria parasitica

As in plants, fungi exhibit wide variation in reproductive strategies and mating systems. Although most sexually reproducing fungi are either predominantly outcrossing or predominantly selfing, there are some notable exceptions. The haploid, ascomycete chestnut blight pathogen, Cryphonectria parasitica, has previously been shown to have a mixed mating system in one population in USA. In this report, we show that both selfing and outcrossing occur in 10 additional populations of C. parasitica sampled from Japan, Italy, Switzerland and USA. Progeny arrays from each population were assayed for segregation at vegetative incompatibility (vic) and DNA fingerprinting loci. Outcrossing rates (t(m)) were estimated as the proportion of progeny arrays showing segregation at one or more loci, corrected by the probability of nondetection of outcrossing (alpha). Estimates of t(m) varied from 0.74 to 0.97, with the lowest rates consistently detected in USA populations (0.74-0.78). Five populations (four in USA and one in Italy) had t(m) significantly less than 1, supporting the conclusion that these populations exhibit mixed mating. The underlying causes of variation in outcrossing rates among populations of C. parasitica are not known, but we speculate that--as in plants--outcrossing is a function of ecological, demographic and genetic factors.

Spatial and Genetic Analysis of a Flag Shoot Subpopulation of Erysiphe necator in Italy

ABSTRACT Erysiphe necator overwinters as ascospores in cleistothecia and mycelium in dormant buds of grapevines. Shoots developing from infected buds early in the growing season are covered with dense mycelium and are known as "flag shoots". Combining epidemiological and genetic analyses, the objective of this study was to analyze the spatial and genetic structure of a flag shoot subpopulation of E. necator as a way to assess the contribution of flag shoots as primary inoculum, and to determine if flag shoot subpopulations are clonal with only one mating type. One vineyard in Tuscany, Italy was surveyed intensively for flag shoots for 8 years; isolations of E. necator were made from flag shoots for 5 years. We observed distinct disease foci developing around flag shoots early in epidemics, demonstrating a steep dispersal gradient of conidia and the importance of flag shoots as primary inoculum sources. Flag shoots were spatially aggregated within and between years, most likely as a result of short-distance dispersal of conidia from flags early in the season when dormant buds for the next year's shoots are formed and are susceptible to infection. The two mating types were found in 1:1 ratios in this flag shoot subpopulation. Genotypic diversity, based on inter-simple sequence repeat markers, was high in all years with only two haplotypes occurring twice, and subpopulations were genetically differentiated between years. Similarities between haplotypes were not spatially autocorrelated. One multilocus analysis of population structure is consistent with the hypothesis of random mating but another is not. These results are not consistent with expectations for a strictly clonal or strictly randomly mating flag shoot subpopulation. Instead, the hypothesis that the flag shoot subpopulation of E. necator may reproduce clonally and sexually needs further testing.

Biological control of chestnut blight with hypovirulence: a critical analysis

Most hypovirulence in the chestnut blight fungus, Cryphonectria parasitica, is associated with infection by fungal viruses in the family Hypoviridae. Hypovirulence has controlled chestnut blight well in some locations in Europe and in Michigan in the United States. In contrast, with few exceptions, biological control has failed almost completely in eastern North America. Therapeutic treatment of individual cankers is successful in most cases, but the success of hypovirulence at the population level depends on the natural spread of viruses. Characteristics of three interacting trophic levels (virus, fungus, and tree), plus the environment, determine the success or failure of hypovirulence. Vegetative incompatibility restricts virus transmission, but this factor alone is a poor predictor of biological control. Any factor reducing the rate of chestnut blight epidemics enhances hypovirus invasion. Overall, however, not enough is understood about the epidemiological dynamics of this system to determine the crucial factors regulating the establishment of hypovirulence in chestnut forests.

Programmed cell death correlates with virus transmission in a filamentous fungus

Programmed cell death (PCD) is an essential part of the defence response in plants and animals against pathogens. Here, we report that PCD is also involved in defence against pathogens of fungi. Vegetative incompatibility is a self/non-self recognition system in fungi that results in PCD when cells of incompatible strains fuse. We quantified the frequency of cell death associated with six vegetative incompatibility (vic) genes in the filamentous ascomycete fungus Cryphonectria parasitica. Cell death frequencies were compared with the effects of vic genes on transmission of viruses between the same strains. We found a significant negative correlation between cell death and virus transmission. We also show that asymmetry in cell death correlates with asymmetry in virus transmission; greater transmission occurs into vic genotypes that exhibit delayed or infrequent PCD after fusion with an incompatible strain. Furthermore, we found that virus infection can have a significant, strain-specific, positive or negative effect on PCD. Specific interactions between vic gene function and viruses, along with correlations between cell death and transmission, strongly implicate PCD as a host-mediated pathogen defence strategy in fungi.

Genetic control of horizontal virus transmission in the chestnut blight fungus, Cryphonectria parasitica

Vegetative incompatibility in fungi has long been known to reduce the transmission of viruses between individuals, but the barrier to transmission is incomplete. In replicated laboratory assays, we showed conclusively that the transmission of viruses between individuals of the chestnut blight fungus Cryphonectria parasitica is controlled primarily by vegetative incompatibility (vic) genes. By replicating vic genotypes in independent fungal isolates, we quantified the effect of heteroallelism at each of six vic loci on virus transmission. Transmission occurs with 100% frequency when donor and recipient isolates have the same vic genotypes, but heteroallelism at one or more vic loci generally reduces virus transmission. Transmission was variable among single heteroallelic loci. At the extremes, heteroallelism at vic4 had no effect on virus transmission, but transmission occurred in only 21% of pairings that were heteroallelic at vic2. Intermediate frequencies of transmission were observed when vic3 and vic6 were heteroallelic (76 and 32%, respectively). When vic1, vic2, and vic7 were heteroallelic, the frequency of transmission depended on which alleles were present in the donor and the recipient. The effect of heteroallelism at two vic loci was mostly additive, although small but statistically significant interactions (epistasis) were observed in four pairs of vic loci. A logistic regression model was developed to predict the probability of virus transmission between vic genotypes. Heteroallelism at vic loci, asymmetry, and epistasis were the dominant factors controlling transmission, but host genetic background also was statistically significant, indicating that vic genes alone cannot explain all the variation in virus transmission. Predictions from the logistic regression model were highly correlated to independent transmission tests with field isolates. Our model can be used to estimate horizontal transmission rates as a function of host genetics in natural populations of C. parasitica.

Variation in tolerance and virulence in the chestnut blight fungus-hypovirus interaction

Chestnut blight, caused by the fungus Cryphonectria parasitica, has been effectively controlled with double-stranded RNA hypoviruses in Europe for over 40 years. The marked reduction in the virulence of C. parasitica by hypoviruses is a phenomenon known as hypovirulence. This virus-fungus pathosystem has become a model system for the study of biological control of fungi with viruses. We studied variation in tolerance to hypoviruses in fungal hosts and variation in virulence among virus isolates from a local population in Italy. Tolerance is defined as the relative fitness of a fungal individual when infected with hypoviruses (compared to being uninfected); virulence is defined for each hypovirus as the reduction in fitness of fungal hosts relative to virus-free hosts. Six hypovirus-infected isolates of C. parasitica were sampled from the population, and each hypovirus was transferred into six hypovirus-free recipient isolates. The resulting 36 hypovirus-fungus combinations were used to estimate genetic variation in tolerance to hypoviruses, in hypovirus virulence, and in virus-fungus interactions. Four phenotypes were evaluated for each virus-fungus combination to estimate relative fitness: (i) sporulation, i.e., the number of asexual spores (conidia) produced; (ii) canker area on field-inoculated chestnut trees, (iii) vertical transmission of hypoviruses into conidia, and (iv) conidial germination. Two-way analysis of variance (ANOVA) revealed significant interactions (P < 0.001) between viruses and fungal isolates for sporulation and canker area but not for conidial germination or transmission. One-way ANOVA among hypoviruses (within each fungal isolate) and among fungal isolates (within each hypovirus) revealed significant genetic variation (P < 0.01) in hypovirus virulence and fungal tolerance within several fungal isolates, and hypoviruses, respectively. These interactions and the significant genetic variation in several fitness characters indicate the potential for future evolution of these characters. However, biological control is unlikely to break down due to evolution of tolerance to hypoviruses in the fungus because the magnitudes of tolerance and interactions were relatively small.

Identification and Spread of Fomitiporia punctata Associated with Wood Decay of Grapevine Showing Symptoms of Esca

ABSTRACT A full understanding of the pathology of esca, a chronic disease of grapevines, has been problematic, in part because the identity of the pathogen (or pathogens) has been difficult to determine. The wood decay symptoms of esca have been most often associated with Phellinus igniarius or Fomitiporia punctata. However, Koch's postulates have not been completely fulfilled because symptoms take many years to develop. The goal of this study was to determine the identity and mode of spread of basidiomycetes associated with wood decay in vines showing esca symptoms in Italian vineyards. Vineyards were intensively studied for the presence of basidiocarps, and mycelium was isolated from symptomatic vines. Fruiting bodies were identified by morphology, while mycelial isolates were identified by restriction fragment length polymorphism analysis of the internal transcribed spacer region of the nuclear ribosomal RNA gene cluster. Fomitiporia punctata fruiting bodies and mycelium were associated with approximately 50% of the vines showing esca symptoms in two vineyards; P. igniarius was not found in any samples. Fruiting bodies of F. punctata were found in five of six vineyards examined, but at low frequencies except in one vineyard. The diversity of somatic incompatibility types was very high; isolates from almost every vine had different somatic incompatibility types. With few exceptions, symptomatic and dead vines were not spatially aggregated within 12 vineyards. The combination of diverse somatic incompatibility types and lack of spatial aggregations are not consistent with the hypothesis that the disease is spread clonally through roots or by pruning tools. The correct identity of basidiomycetes associated with wood decay of vines with esca symptoms is important for understanding the epidemiology of this disease because F. punctata is found commonly on many woody hosts in Europe, which may represent a potential inoculum source for this disease.

Relationship Between Biological Control, Incidence of Hypovirulence, and Diversity of Vegetative Compatibility Types of Cryphonectria parasitica in France

ABSTRACT In France, chestnut blight, caused by Cryphonectria parasitica, has been controlled since 1974 in orchards, but never in coppice forests, by releasing hypovirulent strains infected with CHV1 hypovirus. We tested the hypothesis that this biological control (BC) has lead to a decrease in blight severity, spread of hypovirulence, and change in C. parasitica populations. The low severity of chestnut blight was confirmed in the six regions studied (subdivided into zones). The remission of cankers was associated with the presence of white isolates presumed to be hypovirulent. These two parameters were also correlated, at the zonal level, to the frequency of sites where BC was used. However, the estimates of the natural background level of hypovirulence, independent of BC, ranged from 4% in forests in Dordogne to 60% in orchards in Lozère. Differences in the rate of hypovirulent isolates among regions were consistent with the diversity of vegetative compatibility (VC) types in populations of C. parasitica. The highest VC-type diversity and mean allelic diversity for known vegetative incompatibility (vic) genes were observed in Dordogne. We showed that the current diversity of VC types in populations of C. parasitica was lower than in 1981. We found 30 VC types among 1,113 isolates of C. parasitica. Ten VC types were incompatible with known EU testers, suggesting that one additional vic gene or allele at one of the six vic loci known should be present in Europe.

Analysis of population structure of the chestnut blight fungus based on vegetative incompatibility genotypes

Vegetative incompatibility is a self/nonself-recognition system in fungi that has often been used for describing phenotypic diversity in fungal populations. A common hypothesis is that vegetative incompatibility polymorphisms are maintained by balancing selection. However, understanding the evolutionary significance of vegetative incompatibility and the factors that maintain these polymorphisms has been limited by a lack of knowledge of the underlying genetics of vegetative compatibility (vc) types. Genotypes of 64 vc types, controlled by six unlinked vegetative incompatibility (vic) loci, have been identified in the chestnut blight fungus, Cryphonectria parasitica. By interpreting vc type survey data in terms of vic genotypes, we estimated vic-allele frequencies and analyzed the multilocus genetic structure of 13 populations in Europe and 3 populations in the U.S. European populations have less vc type diversity than the US populations because of a combination of lower vic-allele diversity and limited recombination. Genotypic diversity of 10 populations in Italy correlated to the abundance of sexual structures; however, significant deviations from random mating suggest that either sexual reproduction may not contribute many offspring in these populations or that vic genes (or vic genotypes) are under selection. Most vic-allele frequencies deviated from 0.5, the equilibrium frequency predicted under frequency-dependent selection, providing no evidence for selection acting on these loci.

Behavioural responses and biochemical correlates in Solea solea to gradual hypoxic exposure

The common sole, Solea solea, a benthic flatfish, is frequently exposed to environmental hypoxic conditions. A succession of behavioural responses to oxygen depletion can be observed. Under moderate hypoxia (80-20% air saturation) the fish reduce spontaneous activity and the scope for activity is lowered. At the onset of anaerobic metabolism (at 20% air saturation) the fish lie still on the bottom, but with increasing severity of hypoxia they start bending the body so as to lift the mouth above the bottom and to reach water layers with higher oxygen concentrations. Between 20 and 6% air saturation, the sole applies two different metabolic strategies: (i) it activates anaerobic metabolism and (ii) it depresses its metabolism below standard metabolic rate. At 5% air saturation or lower the fish swim up with burst- and panic-like movements and lose balance and swim in an uncoordinated manner (below 3%), finally remaining paralysed at the bottom. The correlation of behavioural and metabolic responses clearly shows that under unfavourable oxygen conditions, escape behaviour and burst activity are induced as a last response when other energy-saving alternatives (anaerobic metabolism and metabolic depression) seem to become insufficient.

Cleistothecia of Uncinula necator-An Additional Source of Inoculum in Italian Vineyards

Density and viability of populations of cleistothecia of Uncinula necator from bark, leaves, and soil were determined in three vineyards in the Florence and Siena provinces of Tuscany for 3 years. A higher density of cleistothecia was found on fallen leaves than on bark. However, the percentage of viable cleistothecia was higher on bark. No viable cleistothecia were recovered from soil. U. necator overwintered as mycelium in dormant infected buds, which gave rise to flag shoots, only in Santa Cristina, where 20 and 92 flag shoots per hectare were detected before bloom in 1994 and 1995, respectively. Disease incidence and severity increased similarly at Corti, Fornace, and at Santa Cristina, although powdery mildew epidemics started from ascospores only in Corti and Fornace, whereas flag shoots were present at Santa Cristina. Cleistothecia were formed in autumn in both 1994 and 1995, and their dispersal started in late September to mid-October, with the maximum number of cleistothecia trapped in funnels during the second half of October. Cleistothecia appear to function as the sole source of primary inoculum for grape powdery mildew in some Italian vineyards and serve as additional sources of inoculum where the pathogen also overwinters in infected buds. In Australia but not in New York, the pathogen also overwinters as cleistothecia on fallen leaves.

A multicenter randomized trial of comprehensive geriatric assessment and management: experimental design, baseline data, and six-month preliminary results

Between October 1992 and July 1993, 11 Northern Italian geriatric departments systematically screened 1386 inpatients hospitalized for at least 10 days. Of those screened, 74% (N = 1019) were excluded by one or more of 7 exclusion criteria; 32% (N = 118) of the 367 remaining subjects failed to meet more than 1 of 8 inclusion criteria. The 11 Geriatric Evaluation Units (GEUs) examined the remaining eligible 249 inpatients with a uniform comprehensive geriatric assessment (CGA) plan, which included a number of validated assessment scales. Of those evaluated, 39% (N = 97) were ineligible for the study because of being unwilling, noncompliant, too sick or "not truly frail", and the remaining 152 (11% of all patients screened) were randomly enrolled in two groups; 79 were assigned to the GEU (experimental group), and 73 to standard care in the National Health Care System (control group). At entry there was no statistically significant difference between the two groups. At 6 months, preliminary results are encouraging; GEU patients had a lower mortality than controls (2 vs 8, 2.5% vs 10.9%; p < 0.05). Slight differences were seen in both clinical-cognitive-affective-functional status and the use of health and social care resources. Only 3 subjects dropped out, 8 refused further follow-up, and 3 went to a nursing-home. We conclude that a standardized selection plan can recognize frail elderly inpatients and that GEU care seems to achieve good results.