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Climate change is driving the emergence of novel tree diseases at the global scale, requiring new approaches for the formal confirmation of the pathogenicity of novel pathogens on novel hosts. At the same time, predictive models need to account for the possible effect of environmental changes and of abiotic stressors on disease severity for all diseases. By wound-inoculating Botryosphaeria dothidea on potted California coast live oaks and Cryptostroma corticale on potted silver maples, simultaneously in well-watered and in water-deprived conditions, I show that drought conditions increase the severity of disease symptoms. I also show that, by including a water-stressed treatment, I can formally prove pathogenicity and fulfill Koch's postulates for putative pathogens that could not be confirmed in the absence of the stressor. Additionally, I show that the inclusion of data obtained in water stress conditions increases the differentiation between symptoms caused by fungal infection vs. symptoms caused by wound trauma, thus reducing the possible effect of outliers, a significant problem affecting many trials for fulfilling Koch's postulates conducted with a limited number of replicates. The availability of comparable datasets in the presence and the absence of an abiotic stressor allows for the calculation of an Environmental Disease Component Index. Positive values of the index indicate a significant role of environmental change in disease progression and identify those pathogens that must be modeled factoring in climatic stressors. I suggest that this index may be extremely valuable for identifying pathogens likely to become emergent as climate changes. [ABSTRACT FROM AUTHOR]

During the 2022 growing season, commercial crops of onion (Allium cepa cv. Medusa) were found to be affected by an extensive leaf blight in south western Slovakia. The pathogen present on diseased leaves was isolated and identified as Stemphylium vesicarium through morphological and molecular analyses, utilizing three DNA markers (ITS, tef1-α, and β-tubulin). A detailed description and illustration of the fungus are provided. Although this pathogen is already present in Slovakia, this is the first record of S. vesicarium causing leaf blight on A. cepa in the country. Pathogenicity tests with a fungal isolate were performed on three local cultivars of onion plants in the laboratory, indicating varying susceptibility of the cultivars to S. vesicarium. [ABSTRACT FROM AUTHOR]

In 2023 in Aichi Prefecture, shiso plant growth in a deep flow technique (DFT) hydroponic system was delayed from mid-March to late April with roots showing evidence of rotting. An oomycete species was isolated from the roots and identified as Phytopythium helicoides based on morphological characteristics and DNA sequence homology. Identical symptoms appeared on shiso plants after inoculating seedlings with zoospores from the strain, and the same oomycete species was reisolated from the diseased plants. This study is the first report in the world of root rot caused by P. helicoides in shiso in a DFT hydroponic system. [ABSTRACT FROM AUTHOR]

Fungi inflict a great deal of damage to crops in fields and in storage facilities, causing issues such as leaf spot, wilt, rust, dieback and rot, as well as releasing mycotoxins that taint vegetation. In the current study, 25 de novo fungal isolates were taken from infected plant tissue (leaf, root and fruit), at pre- and post-harvest stages. Isolates were identified using molecular markers; 8 genera and 15 species were determined. The most common species was Penicillium spp. (40%), Aspergillus spp. (20%), Fusarium spp. (16%) and Alternaria alternata species (8%). The remaining 16% was comprised of various types of fungi, including Geotrichum candidum, Neofusicoccum parvum, Rhizopus stolonifera and Mucor fragilis. Many of these genera are known to cause significant crop damage and are notorious mycotoxin producers. An evaluation of the optimal growth temperature revealed the ideal temperatures were 30 °C for 56% of isolates, 25 °C for 28% of isolates and 20 °C for 16% of isolates. An assessment of water activity showed that 60% of isolates belonged to Penicillium and Aspergillus spp. and were mesophilic and xerophilic. Another 28% of isolates were Fusarium spp., Geotrichum candidum, Neofusicoccum parvum and Mucor fragilis, and hydrophilic. The remaining 12%, representing Alternaria alternata and Rhizopus stolonifera, were mesophilic. The current study provides accurate eco-physiological response data and molecular information for each isolate. The findings can assist the development of novel approaches to control the expansion of invasive fungal infections and minimise their deleterious consequences. [ABSTRACT FROM AUTHOR]

This study represents the molecular characterization of Basidiobolus sp., isolated from gastrointestinal basidiobolomycosis in rainbow trout, Oncorhynchus mykiss in India. Basidiobolus spp. is a zoonotic fungal pathogen that can cause gastrointestinal, cutaneous or subcutaneous, visceral and colonic basidiobolomycosis in immunocompetent individuals of all genders and ages. The strain was recovered from ascitic fluid of moribund rainbow trout, which upon necropsy exhibited liquefaction and swelling of internal organs, as well as red-yellow drainable and foul-smelling ascites (150.5 ± 15.9 mL). The ascitic fluid was subjected to microscopic analysis, which revealed the presence of irregular, spore-forming fungal hyphae characterized by large size and sparse septation, with a diameter of 25.6 ± 4.9 µm and thin walls. Additionally, thick-walled zygospores measuring 35.9 ± 7.9 µm in diameter, exhibiting a single outer beak-like projection on the spore surface, were also detected. Furthermore, examination of the 72-h-old fungal culture displayed a furrowed, waxy colony with a raised center and flat edges, indicative of its unique morphology. The isolate demonstrated β-hemolysis and the capability to degrade protein, nucleic acid, gelatin, urea, and lipid. The amplification of RNA internal transcribed spacer (ITS) for amplicon size of 680 bp, phylogenetic analysis, calculation of genetic distance similarity (%), and haplotype networking confirmed that the isolate was Basidiobolus sp. Ind SN1 (MW 928426). Basidiobolus sp. Ind SN1 shared 97.82%, 96.59%, and 92.32% sequence similarity with Basidiobolus meristosporus (MH857419), B. meristosporus (FJ786040), and B. heterosporus (EF392521), respectively. The disease caused by Basidiobolus sp. Ind SN1 was successfully reproduced in rainbow trout through experimental infection, satisfying Koch's postulate. Histopathological examination of the liver, kidney, and gill of the infected rainbow trout revealed hydropic degeneration of hepatocytes, necrotic kidney tubules, and lamellar hyperplasia, respectively. This study also identifies rainbow trout as a novel host for Basidiobolus sp., highlighting the emergence of a fungal pathogen that could potentially lead to fatal infections in fish farming systems. Thus, it is recommended that fish culturists, aquaculture entrepreneurs, and fish handlers should maintain proper sanitation and good animal husbandry practices to minimize the risk of basidiobolomycosis in aquaculture. [ABSTRACT FROM AUTHOR]

In February 2023 in Japan, seedlings of wax gourd [Benincasa hispida (Thunb.) Cogn.] in seedling boxes developed water-soaked rot on hypocotyls typical of damping off and eventually died. A Pythium sp. was isolated from the hypocotyls and was identified as Pythium aphanidermatum based on morphological characteristics and DNA sequence data. The same symptoms developed after seedlings were inoculated with the isolated fungus, and the same fungus was reisolated from the seedlings. This is the first report of damping off in wax gourd seedlings caused by P. aphanidermatum in seedling boxes in Japan. [ABSTRACT FROM AUTHOR]

Sorghum is the fifth most important cereal crop in the world. There is a high potential for sorghum production in Indonesia because of its drought tolerance and wide adaptability. Sorghum cultivation is constrained in Indonesia by pests and diseases. One such disease is tar-spot caused by the Phyllachora sp., an obligate fungal pathogen. Tar spot disease of sorghum has not been widely reported. This study reports the finding of Phyllachora species based on the morphology and molecular identification of tar spot on leaves of sorghum plants of Latu Monca and Latu Kaca local varieties.The pathogen was identified as Phyllachora species. This is the first report of tar spots of sorghum caused by Phyllachora in West Lombok Regency, West Nusa Tenggara Province, Indonesia. [ABSTRACT FROM AUTHOR]

Soybean is one of the most important crops grown worldwide and accounting for significant global trade including transgenic soybean. The crop is attacked by several seed-borne fungal pathogens and some of them are of quarantine concern for India. Keeping in view of the risks associated with movement of soybean seeds, sensitive and reliable molecular diagnostics have been developed for precise and simultaneous detection of three pathogens of quarantine concern for India namely, Diaporthe phaseolorum (stem blight), D. longicolla (seed decay), Peronospora manshurica (downy mildew), along with Macrophomina phaseolina causing dry root rot. The targeted pathogens after isolation from imported transgenic and non-transgenic soybean seeds were identified. Quadruplex and qPCR assays were developed targeting the sequences of different genes such as Histone-3 for detection of D. longicolla and M. phaseolina. The markers DlHisF2&R2 and MpHisF1&R1 produced 265 and 309 bp amplicons for D. longicolla and M. phaseolina, respectively. Actin gene based marker DpActF1&R2 was developed for D. phaseolorum which provided 113 bp amplicon whereas, COX2 based marker PmCoxF2&R2 was developed for P. manshurica with amplified product of 152 bp. During qPCR analysis, these markers proved highly specific and sensitive for detection of these pathogens up to 0.1 pg of template DNA. Quadruplex PCR protocol was also developed by combining these specific markers which could distinguish all the targeted pathogens simultaneously in a single reaction. The developed diagnostic protocols are extremely valuable for quarantine clearance and to ensure the safe transboundary exchange and healthy conservation of germplasm in the National Genebank. [ABSTRACT FROM AUTHOR]

Pomegranate is an important horticultural crop grown in arid and semi-arid regions worldwide. Moreover, due to its widespread nutraceutical and pharmaceutical properties, expansion in its cultivated area has taken place extensively in India which has now become a global leader in its production and export. However, due to changing climatic conditions a plethora of diseases affect its quality and yield. Recently, we observed a typical collar rot occurring on pomegranate plants with 10–25% incidence. The current study was undertaken to identify the causative organism and prove its pathogenicity on pomegranate plants. Therefore, isolation of fungi was carried out using symptomatic tissues. Among the isolated fungi, one of the fungi was recovered up to 80% and, therefore, it was evaluated further. The colony morphology and other microscopic features suggested that it belonged to the genus Calonectria. Homology search using reliable barcode regions, both coding and non-coding, revealed close genetic similarities between the isolate and C. hawksworthii. Pathogenicity tests were performed on pomegranate seedlings, groundnut seedlings (a susceptible host to Calonectria sp.) and 6-month-old pomegranate plants. Artificially inoculated seedlings/plants developed typical symptoms while control plants did not, proving that the isolate was pathogenic. Hence, based on morphological and molecular data we identified the pomegranate collar-rot causal organism as C. hawksworthii, which is a novel record and highlights the expansion in geographical distribution and host range of the fungus. [ABSTRACT FROM AUTHOR]

One of the most harmful diseases that infect maize plants is Fusarium wilt caused by Fusarium oxysporum. The novelty of this study was to investigate the antifungal and plant growth-promoting properties of some rhizobacteria (PGPR). PGPR enhances plant growth and manages plant diseases. In this study, some bacterial isolates were isolated from the rhizosphere of rice plants and selected based on their ability to produce β-1,3 glucanase. The two bacterial isolates that produced higher concentrations of β-1,3 glucanase were selected to complete the study and identified by 16S rDNA sequences as Pseudomonas pseudoalcaligenes with accession number EU921258 and Bacillus pumilus with accession number EU921259. Different biochemical properties of the two bacterial isolates were investigated. Additionally, the effectiveness of P. pseudoalcaligene and B. pumilus against Fusarium oxysporum, which causes maize wilt disease was assessed. The results showed that P. pseudoalcaligenes and B. pumilus, either alone or in combination caused a significant reduction in the percentage of disease severity and an increment in the percentage of protection. In addition, infection with Fusarium caused a significant decrease in the morphological parameters, photosynthetic pigments, and cell membrane stability as compared to healthy control plants. However, lipid peroxidation, osmoprotectant compounds (soluble sugars, glycine betaine, and proline), secondary metabolites (phenol, flavonoid, and lignin content), and the enzymatic antioxidants increased significantly in infected plants as compared to healthy control plants. Furthermore, inoculation with P. pseudoalcaligenes and B. pumilus alone or in a combination caused significantly increased in the morphological parameters, photosynthetic pigment, and cell membrane stability in infected plants. Induction of β-1,3 glucanase gene in maize was not recorded in non-inoculated plants, but detected in inoculated plants with P. pseudoalcaligenes and B. pumilus alone or in combination as 2.4 kb bands on agarose gel electrophoresis. In conclusion, PGPR is regarded as an environmentally friendly method of protecting plants from pathogen infection and increasing plant growth without the use of pesticides, which cause a variety of environmental pollutions. [ABSTRACT FROM AUTHOR]

European canker is one of the most devastating fungal diseases of apple in most temperate regions. The causal agent, Neonectria ditissima, infects trees through wounds in the bark forming cankers that girdle the stem and eventually cause tree death. Timely protection of the trees is challenged by stagnation of symptom expression after infections for a long period of time. The objective of this research is to use a novel TaqMan PCR assay to detect and quantify N. ditissima during the asymptomatic colonization of apple wood. Pruning wounds on branches of the cultivars Elstar and Gala were inoculated with N. ditissima and wood discs were sampled at 2–6, 10–14, and 30–34 mm distance from the inoculation site after 3 hours, 2 weeks, 4 weeks and 8 weeks for the detection and quantification of the pathogen. The TaqMan PCR assay detected N. ditissima in 51% of the inoculated apple tree samples. This was more sensitive than the culturing method detecting N. ditissima in 11% of the samples. An accumulation of N. ditissima DNA up to 34 mm distance from the inoculation site was observed without development of visible symptoms. To our knowledge this is the first time colonization of N. ditissima was detected and quantified in the absence of symptoms of European canker. The implications of this research are discussed. [ABSTRACT FROM AUTHOR]

Numerous complex chemicals are being routinely used to prevent pathogens in various commercially important agri-horticultural crops that have some biosafety issues associated with human health and environment. Therefore, the present study was aimed to develop resistance in tomato against soil-borne fungal pathogen Fusarium oxysporum f. sp. lycopersici, through in vitro cell line selection approach. BLASTn analysis of sequenced 16S rRNA region of the fungus isolated from the wilt infected tomato plant was confirmed by ITS gene technology. Highest callus induction (79.63 ± 0.70%) along with shoot regeneration (78.68 ± 0.64%) was recorded on MS medium fortified containing 4.54 µM TDZ + 2.90 µM IAA and 2.27 µM TDZ + 1.0 µM 2,4-D using leaf explants, respectively. To carry out in vitro selection, developed calli using leaf explants were further subjected on selective medium followed by discontinuous selection cycles supplemented with 30% culture filtrate (CF) of targeted pathogen, where 21.32 ± 0.99 per cent average callus survival and 45.98 ± 0.55% average shoot induction (devoid of CF) were recorded. 12 moderately resistant lines were obtained from the total 48 cell lines during in vivo bioassay under glass house conditions. Two somaclones were confirmed at molecular level among the total 12 moderately developed resistant cell lines. The multilocation field trials are being done to check stable inheritance with generation wise advancements. It was inferred from the present study that these findings could be a cutting edge to develop resistance against various stresses in commercially important horticultural crops like tomato without posing any threat to environment. Key message: Two tolerant tomato somaclones developed against Fusarium oxysporum f. sp. lycopersici causing Fusarium wilt disease using an ecofriendly research methodology of in vitro cell line selection approach. [ABSTRACT FROM AUTHOR]

The article presents experimental data on the species composition of fungal and viral pathogens in the secondary range of Lupinus polyphyllus Lindl. Tobacco mosaic virus, bean yellow mosaic virus, bean common mosaic virus, and pea enation mosaic virus were diagnosed for the first time on L. polyphyllus. Issues related to the peculiarities of the adaptability of viruses to invasive plant species are discussed. The preventive role of virus vectors (Aphididae) in the expansion of viruses and the expansion of the spectrum of host plants (susceptible species) is emphasized. Interaction with vectors, including the nonspecific species, is one of the mechanisms for the adaptability of viruses, their expansion into new regions, and the formation of new pathosystems with invasive plant species. It was concluded that it is possible to predict the search for the most effective variants of harmful organisms on the basis of the analysis of the trophic relationships of vectors for the biocontrol of L. polyphyllus. [ABSTRACT FROM AUTHOR]

Dieback disease, caused by the fungal pathogen Botryosphaeria dothidea, has been identified as affecting apricot trees in Korea for the first time. The disease was observed in several orchards in Wanju Province, with symptoms including sunken lesions on branches and wilting of infected trees. The causal agent was identified through fungal isolations and molecular identifications, confirming the presence of B. dothidea. Pathogenicity tests further demonstrated that the fungal isolates were indeed responsible for the disease. This report highlights the need for accurate identification of the causal agent to implement effective disease management strategies in the apricot industry. [Extracted from the article]

Fungal pathogens constantly sense and respond to the environment they inhabit, and this interaction is vital for their survival inside hosts and exhibiting pathogenic traits. Since such responses often entail specific patterns of gene expression, regulators of chromatin structure contribute to the fitness and virulence of the pathogens by modulating DNA accessibility to the transcriptional machinery. Recent studies in several human and plant fungal pathogens have uncovered the SWI/SNF group of chromatin remodelers as an important determinant of pathogenic traits and provided insights into their mechanism of function. Here, we review these studies and highlight the differential functions of these remodeling complexes and their subunits in regulating fungal fitness and pathogenicity. As an extension of our previous study, we also show that loss of specific RSC subunits can predispose the human fungal pathogen Candida albicans cells to filamentous growth in a context-dependent manner. Finally, we consider the potential of targeting the fungal SWI/SNF remodeling complexes for antifungal interventions. [ABSTRACT FROM AUTHOR]

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum (Lib.) De Bary, is one of the most devastating diseases of tomato. The control of the pathogen is challenging because of its high genetic variability, broad host range and lack of information on natural resistance in tomato germplasm. Through the availability of the genome sequence of S. sclerotiorum, progress has been made in the identification of genes associated with the early stages of pathogenesis. However, less than 60 genes have been functionally validated. Very little information is available on the function of genes associated with the later stage of pathogenesis and signalling pathways. Researches related to SSR management have addressed agricultural practices and the application of fungicides. Agricultural practices like field sanitisation, soil sterilisation, biofumigation and organic amendments have shown improvement in disease control, while smart crop monitoring using unmanned aerial systems and optical sensors can further aid in early detection. Application of biological fungicides has demonstrated potential in SSR control in tomato, while the application of ultraviolet radiation can further aid in sustainable disease control. Transgenic approaches via the expression of some genes targeting degradation of the important molecule of pathogenesis or overexpression of the tomato defence-related genes have shown promises to enhance resistance. However, the generation of disease-resistant varieties in tomato is still in infancy. This review focuses on the current advancement of S. sclerotiorum-tomato pathosystem research and identifies some gaps in knowledge while providing recommendations for future research towards sustainable control of SSR in tomato. [ABSTRACT FROM AUTHOR]

In September 2019, small black spots were observed on mature calyces of Cape gooseberry (Physalis pruinosa L.) in a commercial greenhouse in Japan, which markedly decreased their commercial value. A fungus was isolated from a mature calyx and identified as Cladosporium tenuissimum based on morphological examination and molecular analysis using internal transcribed spacers (ITSs). Inoculation of mature calyces with the isolated fungus resulted in the same symptoms, and the fungus was reisolated from the diseased calyx. This is the first report on sooty spot on mature calyces of Cape gooseberry. [ABSTRACT FROM AUTHOR]

Non-native plants may meet little resistance in the novel range if they leave their biological enemies at home. As a result, species invasion can be rapid and appear unlimited. However, with time, organisms may acquire novel enemies in the novel range, or home-range enemies also may colonize the novel range. For plants, several authors have suggested that enemy release may give way to enemy acquisition in which pathogens accumulate and suppresses non-native plants. The 'naturalization' that occurs with acquired enemies may take decades to develop, yet most species invasion research lasts less than 4 years, and data tracking plant invasion before and after the appearance of pathogens are rare. Microstegium vimineum is an Asian grass that has invaded deciduous forest habitats in the southern Midwestern and Southeastern USA and is currently expanding in the Northeastern USA. We recorded widespread expansions in M. populations in North Carolina and Georgia (USA) between 2009 and 2011 but noticed that a fungal pathogen (indicated by leaf lesions; Bipolaris sp.) appeared on several of the populations in 2011. In 2019, we re-sampled these populations to determine whether the appearance of the fungal pathogen corresponded with a suppression of M. vimineum expansion. We found the once-expanding M. vimineum populations in retreat in 2019, and the plant population contractions were greater (and seed production lesser) where the fungal leaf spot disease was most extensive. These results suggest that enemy acquisition suppressed an active non-native plant invasion. We also found that where M. vimineum populations declined (or disappeared) native plants appeared to fill in the gap. Hence, whereby exotic species may gain advantage in novel habitat with the loss of their native-range pathogens, with longer time spans, enemy release may give way to enemy acquisition and native populations may recover if they are immune to the pathogens. [ABSTRACT FROM AUTHOR]

The mutant allele of rice calmodulin-binding transcription activator OsCBT, oscbt-1, exhibits broad-spectrum resistance against rice pathogens. Previously, we reported that the strong resistance of the oscbt-1 mutant to pathogens was conferred by a constitutive upregulation of defense-related genes even under pathogen-free conditions. We also found strong induction of the hypersensitive response as a reaction to pathogen invasion. The results suggest that OsCBT acts as a negative regulator of basal resistance to pathogen attack. To identify the transcriptional network regulated by OsCBT, we compared global gene expression profiles between wild-type (WT) and oscbt-1 rice plants grown under pathogen-free conditions. The results of a 3′ tiling microarray revealed that in oscbt-1 plants, 81 genes are upregulated and 200 genes are downregulated when compared with the WT. A gene ontology analysis showed that differentially regulated genes in oscbt-1 were very closely associated with "death" GO term in a biological process category, and "catalytic activity" and "binding" GO terms in a molecular function category. A MapMan analysis indicated that the functions of these genes were associated with plant responses to biotic stress. Moreover, the results from quantitative real-time PCR in the oscbt-1 mutant showed a significant effect on the gene expression patterns of the fungal pathogen response. Our results suggested that the OsCBT regulates a rice defense response by modulating the expressions of various defense-related genes. [ABSTRACT FROM AUTHOR]

In November 2015, leaf blight on Schima mertensiana was found in Chichijima, Bonin Islands, Tokyo, Japan. The causal fungus was isolated from the leaf symptoms and identified as Colletotrichum sp. based on morphological examination and molecular analysis using ITS, ACT, CHS-1, CAL, and TUB2 sequences. Leaf blight similar to the natural symptoms developed after leaves were inoculated with the isolate. This is the first report of leaf blight on S. mertensiana caused by Colletotrichum species in Japan, and anthracnose, "tanso-byo" in Japanese, is proposed as the disease name. [ABSTRACT FROM AUTHOR]

Emerging infectious diseases are a severe conservation threat for a variety of plants and animals. In North America, several bat species are threatened by white-nose disease, which has caused an unprecedented mass mortality of > 6 million bats since 2006. The fungus Pseudogymnoascus (Geomyces) destructans is the causative agent of the disease. Though asexual reproduction is the norm, sexual reproduction is possible as two mating types exist. Sexual reproduction has been implicated in the emergence of virulent strains of fungi but to date no rapid means of mating type characterisation was available for P. destructans. In this study, three mating type-specific primer sets were designed and tested on 80 isolates. The primers were multiplexed with microsatellite loci allowing for rapid and concurrent genotyping and mating type assignment. These markers will have great utility in better understanding and predicting the population dynamics and evolutionary potential of this fungus, including the emergence of virulent strains. [ABSTRACT FROM AUTHOR]

Cladode brown spot (CBS) is an important disease of Nopalea cochenillifera in the semiarid region of Northeastern Brazil. It has been reported in several countries, but its etiology is controversial, attributed to a complex of pathogens. Fifty fungal isolates were obtained and identified based on morphology and phylogeny, through analysis of the ribosomal DNA internal transcribed spacers (ITS), translation elongation factor 1-alpha (TEF1-alpha), β-tubulin (TUB-2), second largest subunit of RNA polymerase (RPB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the mating type locus MAT1–2 (ApMAT) partial gene sequences. Seven fungal general and twenty species were identified – Alternaria sp., A. longipes and A. tenuissima; Colletotrichum fructicola and C. siamense; Fusarium lunatum, F. incarnatum, and F. verticillioides; Lasiodiplodia euphorbicola, L. iraniensis, L. pseutheobromae, L. theobromae and Lasiodiplodia sp.; Neofusicoccum batangarum; Neopestalotiopsis australis, N. protearum and Neopestalotiopsis sp.; and Nigrospora sphaerica, N. hainanensis and Nigrospora sp. Four of these species had already been reported on Cactaceae of the genus Opuntia, but only N. batangarum, C. fructicola and C. siamense have been reported to date on the genus Nopalea. All isolates were pathogenic to detached cladodes of N. cochenillifera 'Miúda'. Differences in aggressiveness were observed among the species, with L. iraniensis and F. lunatum characterized as the most aggressive species, whilst F. verticillioides as the least aggressive. This study provide important information on the fungi associated with cladode brown spot and improve the strategies for the management of disease on N. cochenillifera. [ABSTRACT FROM AUTHOR]

Gravid female mushroom sciarid flies, Lycoriella ingenua (Dufour:1839) (Diptera:Sciaridae), were confirmed in laboratory experiments as vectors for the fungal pathogen Trichoderma aggressivum f. aggressivum (Samuels and Gams), causal agent of mushroom green mold disease in mushroom farming. The gravid females acquired the fungal spores when exposed to T. aggressivum cultures, which was confirmed by scanning electron microscopy, the flies vectored T. aggressivum onto clean agar petri dishes, confirmed by new fungal colonies growing on the media and molecular analysis (PCR). Significantly, more T. aggressivum colonies formed on the dishes when flies were left to vector the pathogen for 30 h, as opposed to 18 h. One gravid female fly was able to initiate up to 32 T. aggressivum colonies in a 0.03 m3 area. Frass deposits of mushroom sciarid fly larva reared on T. aggressivum contained viable spores, detected through fungal subcultures and molecular analysis (PCR), confirming that larvae can also vector the fungus. This study supports the heretofore anecdotal evidence that mushroom sciarid flies are part of green mold disease epidemiology on mushroom farms. [ABSTRACT FROM AUTHOR]

Main conclusion: Colletotrichum acutatum M11 produces a diffusible compound that suppresses the biochemical, physiological, molecular and anatomical events associated with the defence response induced by the plant defence elicitor AsES. The fungal pathogen Colletotrichum acutatum, the causal agent of anthracnose disease, causes important economical losses in strawberry crop worldwide and synthetic agrochemicals are used to control it. In this context, the control of the disease using bioproducts is gaining reputation as an alternative of those toxic and pollutant agrochemicals. However, the success of the strategies using bioproducts can be seriously jeopardized in the presence of biological agents exerting a defence suppression effect. In this report, we show that the response defence induced in plant by the elicitor AsES from the fungus Acremonium strictum can be suppressed by a diffusible compound produced by isolate M11 of C. acutatum. Results revealed that strawberry plants treated with conidia of the isolated M11 or the culture supernatant of the isolate M11 suppress: ROS accumulation (e.g., H2O2, O2·− and NO), cell wall reinforcement (e.g., lignin and callose), and the up-regulation of defence-related genes (e.g., FaPR1, FaCHI23, FaPDF1.2, FaCAT, FaCDPK, FaCML39) induced by the elicitor AsES. Additionally, we show that the defence suppressing effect causes a systemic sensitization of plants. Results presented here highlights the necessity to make an integral study of the microbiome present in soils and plant biosphere before applying defence activation bioproducts to control crop diseases. [ABSTRACT FROM AUTHOR]

Fruit rot is one of the most important diseases of cantaloupe. In June 2016, fruit rot was found in cantaloupe fruit (Cucumis melo var. cantalupo) in Phayao Province, Thailand. The causal fungus was isolated from lesions and identified as Fusarium equiseti based on both morphological characteristics and phylogenetic analysis of combined sequences of the internal transcribed spacer of ribosomal DNA, translation elongation factor 1-alpha and β-tubulin genes. Cantaloupe fruit inoculated with the isolated fungus developed symptoms similar to natural ones in the field. This is the first report of cantaloupe fruit rot caused by F. equiseti in Thailand. [ABSTRACT FROM AUTHOR]

In 1997, Monilinia fructicola and Monilinia laxa, fungi causing brown rot disease in stone fruit (Prunus species), were identified from Western Australia for the first time. Up until then, Monilinia were quarantine species, and importation of stone fruits to W.A. was prohibited. After Monilinia was identified in W.A., importation of stone fruit from sources outside W.A. was progressively permitted. Today, Monilinia is present in all stone fruit production regions in W.A. The aim of this study was to determine if the genotypes responsible for the first incursion subsequently spread, or if new genotypes have since become established. ISSR markers were used to identify the genotype of isolates collected during the initial incursion event in 1997, and compare them with isolates collected subsequently. Eight M. fructicola genotypes were identified, including a monotypic one on a fresh peach imported from the USA. M. fructicola isolates collected during the initial incursion in 1997 and an isolate from cherry collected in South Australia in the same year were all of the same genotype, suggesting fruit or germplasm from S.A. as the source of the W.A. incursion. However, this incursion genotype appears not have persisted, with different genotypes subsequently becoming widely or locally established. Four genotypes of M. laxa were identified. In contrast to M. fructicola, the 1997 incursion genotype of M. laxa has become widely established in W.A., infecting both stone fruits and pome fruits. [ABSTRACT FROM AUTHOR]

This study provides empirical evidence for antagonistic density dependence mechanisms driving sexual reproduction in the wheat fungal pathogen Zymoseptoria tritici. Biparental crosses with 12 increasing inoculum concentrations, in controlled conditions, showed that sexual reproduction in Z. tritici was impacted by an Allee effect due to mate limitation and a competition with asexual multiplication for resource allocation. The highest number of ascospores discharged was reached at intermediate inoculum concentrations (from 5 × 104 conidia mL−1 to 106 conidia mL−1). Consistent with these results for controlled co-inoculation, we found that the intensity of sexual reproduction varied with both cropping period and the vertical position of the host tissues in the field, with a maximum between 25 and 35 cm above the ground. An optimal lesion density (disease severity of 30 to 45%) maximizing offspring (ascospores) number was established, and its eco-evolutionary consequences are considered here. Two ecological mechanisms may be involved: competition for resources between the two modes of reproduction (decrease in the host resources available for sexual reproduction due to their prior use in asexual multiplication), and competitive disequilibrium between the two parental isolates, due to differential interaction dynamics with the host, for example, leading to an imbalance between mating types. A conceptual model based on these results suggests that sexual reproduction plays a key role in the evolution of pathogenicity traits, including virulence and aggressiveness. Ecological knowledge about the determinants of sexual reproduction in Z. tritici may, therefore, open up new perspectives for the management of other fungal foliar pathogens with dual modes of reproduction. [ABSTRACT FROM AUTHOR]

Outbreaks of Pythium porphyrae, a fungus that causes red rot disease can devastate nori production, but studies have focused on the occurrence of P. porphyrae from cultivated hosts compared with the wild ones. An unexpected encounter of P. porphyrae infecting the wild nori seaweed, Pyropia acanthophora, collected from the Philippines prompted the present study. The definitive morphological diagnoses of P. porphyrae infection based from the previous reports were similar to those obtained here. Phylogenetic and haplotype analyses of nuclear rRNA internal transcribed spacer sequences confirmed that the pathogen infecting the Philippine Py. acanthophora can be assigned to P. porphyrae. [ABSTRACT FROM AUTHOR]

This article, published in the Journal of Plant Pathology, reports on the first case of Rhizopus microsporus causing soft rot in apple fruit in Pakistan. The study describes the symptoms observed on the infected apple fruits, the isolation and identification of the fungus, and the confirmation of its pathogenicity through Koch's postulates. The researchers also note that R. microsporus has previously been reported to cause soft rot on sweet potatoes in Korea. This information provides valuable insights for researchers and practitioners in the field of plant pathology in Pakistan and beyond. [Extracted from the article]

The fungal pathogen Rhizoctonia solani AG8 causes substantial losses to cereal and legume production in Australia and the Pacific Northwest of the United States of America. Mutant analyses have revealed a critical role for ethylene mediated defence signalling for resistance to R. solani AG8 in the model legume Medicago truncatula which is, at least in part, mediated by ethylene dependent accumulation of isoflavonoids. In this study we investigate the potential for members of the ethylene response transcription factor (ERF) family in mediating the isoflavonoid and defence response. A strong and early Rhizoctonia-responsive expression pattern was observed for many of the class IX ERFs in the moderately resistant wild type line A17, while the ethylene insensitive and highly susceptible mutant sickle (skl) showed a very limited regulation of this class. Conversely, the skl mutant demonstrated up-regulation of class II ERFs known to act as transcriptional repressors. Analysis of the presence of the GCC box promoter element, thought to be responsible for ERF binding and transcriptional activity, in genes differentially regulated in A17 suggests indirect or alternative mechanisms of ERF mediated gene regulation may be contributing to the large scale transcriptional adaptation of A17 following R. solani AG8 infection. Comparison of the expression profile with that following infection of A17 and skl with the symbiotic bacterium Sinorhizobium medicae suggests that legumes have adapted the ERF family to perform diverse roles to balance defence against pathogens and symbiosis with beneficial microorganisms in the same root tissue. [ABSTRACT FROM AUTHOR]

Physiological constraints restrict specialist pathogens from infecting new hosts. From an applied perspective, a narrow host range makes specialist pathogens interesting for targeting specific pest insects since they have minimal direct effects on non-target species. Entomopathogenic fungi of the genus Entomophthora are dipteran-specific but have not been investigated for their ability to infect the spotted wing drosophila (SWD; Drosophila suzukii) a fruit-damaging pest invasive to Europe and America. Our main goal was to study whether SWD is in the physiological host range of the entomophthoralean species E. muscae. We investigated pathogenicity and virulence of E. muscae towards its main natural host, the housefly Musca domestica, and towards SWD. We found that E. muscae readily infected and significantly reduced survival of SWD by 27.3% with the majority of flies dying 4-8 days post-exposure. In comparison with SWD, infection of the natural host M. domestica resulted in an even higher mortality of 62.9% and larger conidial spores of E. muscae, reflecting the physiological constraints of the pathogen in the atypical host. We demonstrated that pathogens of the E. muscae species complex that typically have a narrow natural host range of one or few dipteran species are able to infect SWD, and we described a new method for in vivo transmission and infection of an entomophthoralean fungus to SWD. [ABSTRACT FROM AUTHOR]

The presence of honey bees in our landscapes has long invoked images of vitality, diligence, and cooperation. Unfortunately, the current state of bee health paints a rather different picture. The survival of honey bees, as well as the livelihoods of those who benefit from their labor, is under threat from several detractors to bee health. Exposure to pesticides, poor forage, mite parasites, and pathogens has resulted in high annual death of colonies in the USA, Europe, and other parts of the world. Among the suspects thought to contribute to bee decline, the fungal pathogen, Nosema ceranae, is found at high prevalence in both healthy and declining colonies. Since N. ceranae is thought to be a recent parasite of Apis mellifera, much remains unknown about its pathology at the individual and colony levels, as well as how infection may interact and synergize with other stressors. A review of research conducted on N. ceranae infection is provided. Attention is given to observations on detection of infection, cytopathology, viability and infectivity of spores, and caste-specific effects to survival, development, physiology, and behavior. Research findings showing effects from interactions with pesticides and viruses are also provided. Comparisons are drawn between N. ceranae and what is known about a similar, long-recognized pathogen of A. mellifera, Nosema apis. When possible, suggestions for future research that could broaden understanding of N. ceranae and ultimately improve honey bee health are offered to link observations on individual bee pathology with pathology observed at the colony level. [ABSTRACT FROM AUTHOR]

Patients with cystic fibrosis (CF) suffer from chronic lung infections, caused by bacterial, viral or fungal pathogens, which determine morbidity and mortality. The contribution of individual pathogens to chronic disease and acute lung exacerbations is often difficult to determine due to the complex composition of the lung microbiome in CF. In particular, the relevance of fungal pathogens in CF airways remains poorly understood due to limitations of current diagnostics to identify the presence of fungal pathogens and to resolve the individual host-pathogen interaction status. T-lymphocytes play an essential role in host defense against pathogens, but also in inappropriate immune reactions such as allergies. They have the capacity to specifically recognize and discriminate the different pathogens and orchestrate a diverse array of effector functions. Thus, the analysis of the fungus-specific T cell status of an individual can in principle provide detailed information about the identity of the fungal pathogen(s) encountered and the actual fungus-host interaction status. This may allow to classify patients, according to appropriate (protective) or inappropriate (pathology-associated) immune reactions against individual fungal pathogens. However, T cell-based diagnostics are currently not part of the clinical routine. The identification and characterization of fungus-specific T cells in health and disease for diagnostic purposes are associated with significant challenges. Recent technological developments in the field of fungus-specific T helper cell detection provide new insights in the host T cell-fungus interaction. In this review, we will discuss basic principles and the potential of T cell-based diagnostics, as well as the perspectives and further needs for use of T cells for improved clinical diagnostics of fungal diseases. [ABSTRACT FROM AUTHOR]

The devastating bat fungal disease, white-nose syndrome (WNS), does not appear to affect all species equally. To experimentally determine susceptibility differences between species, we exposed hibernating naïve little brown myotis ( Myotis lucifugus) and big brown bats ( Eptesicus fuscus) to the fungus that causes WNS, Pseudogymnoascus destructans ( Pd). After hibernating under identical conditions, Pd lesions were significantly more prevalent and more severe in little brown myotis. This species difference in pathology correlates with susceptibility to WNS in the wild and suggests that survival is related to different host physiological responses. We observed another fungal infection, associated with neutrophilic inflammation, that was equally present in all bats. This suggests that both species are capable of generating a response to cold tolerant fungi and that Pd may have evolved mechanisms for evading host responses that are effective in at least some bat species. These host-pathogen interactions are likely mediated not just by host physiological responses, but also by host behavior. Pd-exposed big brown bats, the less affected species, spent more time in torpor than did control animals, while little brown myotis did not exhibit this change. This differential thermoregulatory response to Pd infection by big brown bat hosts may allow for a more effective (or less pathological) immune response to tissue invasion. [ABSTRACT FROM AUTHOR]

Chytridiomycosis, an amphibian disease caused by the fungal pathogen Batrachochytrium dendrobatidis ( Bd), is an ideal system for studying the influence of temperature on host-pathogen relationships because both host and pathogen are ectothermic. Studies of Bd in culture suggest that optimal growth occurs between 17 and 23°C, and death of the fungus occurs above 29 or below 0°C. Amphibian immune systems, however, are also temperature dependent and often more effective at higher temperatures. We therefore hypothesized that pathogen load, probability of infection and mortality in Bd-exposed frogs would peak at a lower temperature than that at which Bd grows best in vitro. To test this, we conducted a study where Bd- and sham-exposed Northern cricket frogs ( Acris crepitans) were incubated at six temperatures between 11 and 26°C. While probability of infection did not differ across temperatures, pathogen load and mortality were inversely related to temperature. Survival of infected hosts was greatest between 20 and 26°C, temperatures where Bd grows well in culture. These results demonstrate that the conditions under which a pathogen grows best in culture do not necessarily reflect patterns of pathogenicity, an important consideration for predicting the threat of this and other wildlife pathogens. [ABSTRACT FROM AUTHOR]

Eucalyptus has become a preferred species for the production of industrial products and also for the protection of natural forests in South China. Many diseases affect these trees, both on plantations and in nurseries. One such disease in Eucalyptus nurseries is grey mould caused by a species of Botrytis. Symptoms of grey mould were recently observed on stems and leaves of Eucalyptus urophylla × Eucalyptus grandis seedlings in nurseries in ZhanJiang, GuangDong Province, South China. Diseased stems and leaves were covered with mycelium, conidiophores, and conidia of the causal pathogen. The fungus was identified on the basis of DNA sequence comparisons and morphological features, and its pathogenicity was tested on three Eucalyptus clones. Based on sequence comparisons of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA and partial DNA sequences of five nuclear gene regions, glyceraldehyde-3-phosphate dehydrogenase ( G3PDH), heat-shock protein 60 ( HSP60), DNA-dependent RNA polymerase subunit II ( RPB2), necrosis and ethylene-inducing proteins ( NEP1 and NEP2), combined with morphological characteristics and culture growth rate, the fungus represents a previously undescribed species of Botrytis. This undescribed species is phylogenetically and morphologically closely to Botrytis cinerea and B. pelargonii, but can be distinguished from them by DNA sequences of HSP60, RPB2, NEP1, and NEP2 gene regions, conidial characteristics, and culture growth rate. Here, a description of the fungus, designated as Botrytis eucalypti sp. nov., is provided. The results of in vitro leaf inoculation tests demonstrate that B. eucalypti is virulent on all three tested E. urophylla × E. grandis clones. [ABSTRACT FROM AUTHOR]

Phenolic coumarins are secondary metabolites playing an important role in plant-environment interaction. Previously, we have shown that wild tobacco Nicotiana attenuata accumulates high amounts of the jasmonate (JA)-dependent phenolic coumarin, scopoletin, as a phytoalexin to defend itself against a necrotic fungal pathogen, Alternaria alternata (tobacco pathotype). Scopolin, a β-glycoside form of scopoletin, was strongly elicited and to a level even higher than that of scopoletin in host plants after A. alternata infection. However, it was not known whether scopolin functioned as a phytoalexin playing a role in the resistance or simply as a storage form of scopoletin. When supplied in PDA medium, scopolin exhibited a moderate but slightly weaker anti-fungal activity against A. alternata than that of scopoletin. In addition, A. alternata-elicited scopolin level was dramatically decreased in JA deficient plants. Thus, all the data suggest that scopolin is also a JAdependent phytoalexin likely involved in the resistance of N. attenuata against A. alternata. [ABSTRACT FROM AUTHOR]

Main conclusion: Cotton S-adenosylmethionine decarboxylase-, rather than spermine synthase-, mediated spermine biosynthesis is required for salicylic acid- and leucine-correlated signaling in the defense response to Verticillium dahliae. Spermine (Spm) signaling is correlated with plant resistance to the fungal pathogen Verticillium dahliae. We identified genes for key rate-limiting enzymes in the biosynthesis of Spm, namely S- adenosylmethionine decarboxylase ( GhSAMDC) and Spm synthase ( GhSPMS). These were found by screening suppression subtractive hybridization and cDNA libraries of cotton ( Gossypium) species tolerant to Verticillium wilt. Both were induced early and strongly by inoculation with V. dahliae and application of plant hormones. Silencing of GhSPMS or GhSAMDC in cotton leaves led to a significant accumulation of upstream substrates and, ultimately, enhanced plant susceptibility to Verticillium infection. Exogenous supplementation of Spm to the silenced cotton plants improved resistance. When compared with the wild type (WT), constitutive expression of GhSAMDC in Arabidopsis thaliana was associated with greater Verticillium wilt resistance and higher accumulations of Spm, salicylic acid, and leucine during the infection period. By contrast, transgenic Arabidopsis plants that over-expressed GhSPMS were unexpectedly more susceptible than the WT to V. dahliae and they also had impaired levels of putrescine (Put) and salicylic acid (SA). The susceptibility exhibited in GhSPMS-overexpressing Arabidopsis plants was partially reversed by the exogenous supply of Put or SA. In addition, the responsiveness of those two transgenic Arabidopsis lines to V. dahliae was associated with an alteration in transcripts of genes involved in plant resistance to epidermal penetrations and amino acid signaling. Together, these results suggest that GhSAMDC-, rather than GhSPMS-, mediated spermine biosynthesis contributes to plant resistance against V. dahliae through SA- and leucine-correlated signaling. [ABSTRACT FROM AUTHOR]

Cotton yield and quality have been severely compromised by soil sickness throughout the primary cotton-growing regions of China. The aim of this study was to gain insight into the role of rhizosphere microbial community in governing soil sickness of cotton. Plant growth, disease resistance, root exudates, and the composition of the rhizosphere microbial community of cotton were analyzed in two different (4- and 15-year) monocropped soils and in a fallow agricultural soil (control). The monocropped soils significantly influenced cotton growth and root exudates and reduced soil suppressiveness to Fusarium wilt in bioassay experiments. Additionally, pyrosequencing of the whole internal transcribed spacers (ITS1 and ITS2) and 16S rRNA gene amplicons demonstrated clear variations in the microbial composition of cotton rhizosphere between monocropped rhizosphere soils and control soil. Specifically, monocropped soils were characterized by an increase in the abundance of fungal pathogens, including Fusarium oxysporum f. sp. vasinfectum and Verticillium dahliae, relative to the rhizosphere of control soil. Some plant-beneficial and disease-suppressive bacterial taxa, including Xanthomonadaceae, Comamonadaceae, Oxalobacteraceae, and Opitutaceae, were associated with healthy cotton. A significant correlation existed between the presence of certain amino acids (e.g., glutamic acid and alanine) and the above identified taxa, indicating that some constituents in root exudates influenced the microbial compositions of the cotton rhizosphere to manage the disease status of plant in monocropped soils. Collectively, these results suggest that pathogenic fungal build-up and a reduction in the abundance of beneficial rhizobacteria in the rhizosphere contribute to changes in soil suppressiveness to soil-borne pathogens in monocropped soils, resulting in an aggravated level of soil sickness. [ABSTRACT FROM AUTHOR]

The soil-borne ascomycete Gaeumannomyces graminis var. tritici causes take-all of wheat ( Triticum aestivum). Between host crops, G. graminis var. tritici survives saprophytically on crop debris and by infecting susceptible grass weeds or cereal volunteers. Invasion of roots in the following wheat crop results in reduced grain yield and quality. Take-all is commonly assessed in the field by visual inspection. Molecular-based methods are also available to detect G. graminis var . tritici, including a quantitative PCR (qPCR) assay that indirectly measures the amount of pathogen DNA in environmental samples. The qPCR is used as part of a commercial tool (known as PreDicta B™) to predict the risks of take-all in wheat crops prior to planting, which are dependent on the amount of Gaeumannomyces inoculum in field soils. Unfortunately, the costs associated with the PreDicta B™ test can be prohibitive to its use. As a result, in this study, an alternative qPCR assay was developed to measure directly the DNA of G. graminis var . tritici. The assay was shown to detect DNA of G. graminis var. tritici in both symptomatic and non-symptomatic wheat roots, with an increase in the amount of DNA detected having a strong relationship with an increase in take-all symptoms. [ABSTRACT FROM AUTHOR]

Wildlife diseases have been implicated in the declines and extinctions of several species. The ability of a pathogen to persist outside its host, existing as an 'environmental reservoir', can exacerbate the impact of a disease and increase the likelihood of host extinction. Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome in bats, has been found in cave soil during the summer when hibernating bats had likely been absent for several months. However, whether the pathogen can persist over multiple years in the absence of bats is unknown, and long-term persistence of the pathogen can influence whether hibernacula where bats have been locally extirpated due to disease can be subsequently recolonized. Here, we show that P. destructans is capable of long-term persistence in the laboratory in the absence of bats. We cultured P. destructans from dried agar plates that had been kept at 5°C and low humidity conditions (30-40% RH) for more than 5 years. This suggests that P. destructans can persist in the absence of bats for long periods which may prevent the recolonization of hibernation, sites where bat populations were extirpated. This increases the extinction risk of bats affected by this disease. [ABSTRACT FROM AUTHOR]

Eco-friendly strategies pertinent to disease resistance in crops are desired for sustainable agriculture as they minimize chemical input into the agriculture industry. Fungal endophytes with phytohormones secreting capacity are well known for their plant growth promotion but have never been reported previously for their favourable role in plant resistance against pathogens. We studied the role of two fungal endophytes in promoting growth of sunflower ( Helianthus annuus L.) and regulating hormone signalling networks involved in plant defence against fungal infection caused by Alternaria alternata. The two endophytic fungi ( Penicillium citrinum LWL4 and Aspergillus terreus LWL5) promoted growth of sunflower and produced gibberellins (GA, GA, GA, GA, GA, and GA), organic acids (malic, quinic and succinic acid) and siderophore. In A. alternata infected plants, the sole or combined treatment of P. citrinum and A. terreus markedly reduced disease incidence and reprogrammed the host plants to higher growth. The signalling of plant-defence hormones, such as salicylic acid and jasmonic acid fluctuated with the application of sole or combined endophytes in the diseased plants. The endophyte-association regulated oxidative stress responses by activating glutathione and polyphenol oxidase, and down-regulating catalase and peroxidase. In diseased plants, the endophytic-symbiosis rescued plant growth by the overwintering synthesis of free amino acids. In conclusion, the inoculation of endophytes reprogrammed plant growth during disease incidence by regulating the defence-linked responses of the host plant. Exploring endophytic symbiosis can help achieve sustainable agriculture in an eco-friendly way without using fungicides. [ABSTRACT FROM AUTHOR]

The objectives of this study were firstly, to determine the genetic diversity of Monilinia laxa isolates from Hungary, using the PCR-based inter-simple sequence repeat (ISSR) and randomly amplified polymorphic DNA (RAPD) technique; secondly, to prepare genetic diversity groups based on the dendrograms; and finally, to select some relevant isolates to study their fungicide sensitivity. 55 and 77 random amplified polymorphic ISSR and RAPD markers, of which 23 and 18 were polymorphic and 32 and 59 monomorphic, respectively, were used to assess the genetic diversity and to study the structure of M. laxa populations in Hungary. 27 isolates out of 57 ones were confirmed as M. laxa from several orchards (subpopulations) in three geographical regions, in various inoculum sources and in various hosts, were used. 10 fungicides and 12 isolates selected from genetic diversity groups based on the ISSR dendrograms were used to determine the fungicide sensitivity of the selected isolates. The analysis of population structure revealed that genetic diversity within locations, inoculum sources and host ( H) accounted for 99 % of the total genetic diversity ( H), while genetic diversity among locations, inoculum sources and host represented only 1 %. The relative magnitude of gene differentiation between subpopulations ( G) and the estimate of the number of migrants per generation ( Nm) averaged 0.005-0.009 and 53.9-99.2, respectively, for both ISSR and RAPD data set. The results obtained in dendrograms were in accordance with the gene diversity analysis. Grouping of isolates in the dendrograms was irrespective of whether they came from the same or different geographical locations. There was no relationship between clustering among isolates from inoculum sources and hosts. In the fungicide sensitivity tests, five isolates out of 12 were partly insensitive to boscalid+piraclostrobin, cyprodinil, fenhexamid or prochloraz. Obtained results in genetic diversity of M. laxa populations are discussed together with implications for the management of brown rot. [ABSTRACT FROM AUTHOR]

The inhibitory effect of heat treatment (HT) on Botrytis cinerea, a major postharvest fungal pathogen, and the possible mode of action were investigated. Spore germination and germ tube elongation of B. cinerea were both increasingly and significantly inhibited by HT (43 °C) for 10, 20 or 30 min. HT-induced gene expression of NADPH oxidase A, resulted in the intracellular accumulation of reactive oxygen species. HT-treated B. cinerea spores exhibited higher levels of oxidative damage to proteins and lipids, compared to the non-HT control. These findings indicate that HT resulted in oxidative damage which then played an important role in the inhibitory effect on B. cinerea. In the current study, HT was effective in controlling gray mold, caused by B. cinerea, in pear fruits. Understanding the mode of action by which HT inhibits fungal pathogens will help in the application of HT for management of postharvest fungal diseases of fruits and vegetables. [ABSTRACT FROM AUTHOR]

The interplay of host and pathogen life history traits with disease epidemiology and the selective pressures exerted on hosts drives genetic change and the long-term coevolutionary trajectories of host-pathogen associations. Many studies have addressed various aspects of the ways in which hosts and their pathogens interact but have tended to focus on individual populations, on comparisons made at single points in time, or on broader comparisons that confound patterns from different epidemiological and evolutionary units. While such studies provide valuable information, their essentially 'static' snap-shot nature limits the ability to interpret the nature of the underpinning coevolutionary processes. An increasing number of long-term studies involving repeat sampling of multiple interaction demes distributed across space are giving insight into the complexity of the numerical and genetic dynamics of host and pathogen interactions. These illustrate: (a) the ephemerality of disease in individual populations in contrast to its predictability at the metapopulation scale; (b) the spatial and temporal dynamics of selection 'hot-spots', rates of extinction and recolonization; and (c) differences in coevolutionary dynamics among demes within a metapopulation. Such long-term studies further emphasise the interplay between life history traits, time and space, and the importance of developing a framework to classify the seemingly daunting diversity of host-pathogen associations. [ABSTRACT FROM AUTHOR]

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The bacterium Bacillus amyloliquefaciens anti-CA isolated from mangrove system was found to be able to actively kill Candida albicans isolated from clinic. The bacterial strain anti-CA could produce high level of bioactive substance, amylase and protease in the cheap medium containing 2.0 % soybean meal, 2.0 % wheat flour, pH 6.5 within 26 h. After purification, the main bioactive substance was confirmed to be a cyclic lipopeptide containing a heptapeptide, L-Asp→L-Leu→L-Leu→L-Val→L-Val→L-Glu→L-Leu and a 3-OH fatty acid (15 carbons). In addition to C. albicans, the purified lipopeptide can also kill many yeast strains including Metschnikowia bicuspidata, Candida tropicalis, Yarrowia lipolytica and Saccharomyces cerevisiae. After treated by the purified lipopeptide, both the whole cells and protoplasts of C. albicans were destroyed. [ABSTRACT FROM AUTHOR]

This review summarizes the most significant results from the so far existing, but fragmented studies on the potential effects of climate change on wheat pathogens and the diseases they cause. The analysis demonstrates that predictions are uncertain and future disease risk trends must be differentiated on a geographic and time scale. For example, disease incidence of Fusarium head blight in the United Kingdom might increase middle of this century, whereas disease severity of Septoria tritici blotch might decrease in France end of this century. Thus, wheat disease problems caused by a changing climate will probably not consistently worsen, as climatic changes may also improve the crop health situation in wheat depending on the location. The results of long-term simulations of future disease risk must be taken with caution, because different climate models and downscaling methods are used to make the projections and this can create considerable uncertainty. Being aware of this short-coming, plant pathologists recently started to assess the sources of uncertainty related to their long-term disease simulations. However, in spite of this progress there is still a significant lack of simulation studies related to different wheat diseases in various locations that could help to estimate future wheat grain losses due to climatic changes. Many more of these studies are certainly needed. Otherwise, the focus in the climate change debate will remain on the yield loss/gain potential due to changes in the environmental conditions only, which would neglect the important impact of altered biotic constraints such as diseases which are among the key factors in the estimation of future global wheat productivity. [ABSTRACT FROM AUTHOR]

The race of watermelon powdery mildew (PM) present in South Korea was confirmed, and genetic inheritance of resistance to this race was determined from a cultivars 'Arka Manik'. Bioassay tested on a set of melon differential genotypes indicated that the race of P. xathii predominating in South Korea was either belonged to race 1W or another race different from race 2W. Inheritance of PM resistance was studied from F, F, and reciprocal backcross generations derived from 'Arka Manik' (resistant cultivar) × HS3355 (susceptible line). The segregation ratios indicated that resistance to PM in 'Arka Manik' is conditioned by a single incompletely dominant gene ( Pm1.1). Bulked segregant analysis (BSA) of F2 plants using random amplification of polymorphic DNA (RAPD) identified one polymorphic polymerase chain reaction (PCR) band (OP-R483) and a close linkage (3.6 cM) was observed between resistance and OP-483. The marker OP-483 was converted to cleaved amplified polymorphic sequence (CAPS-G/C) and a single nucleotide polymorphism (SNP) marker (MCA-A/G) using melting curve analysis. MCA-A/G marker genotyping of a wide range of susceptible breeding lines revealed that the marker allele of 'Arka Manik' was unique in breeding populations. [ABSTRACT FROM AUTHOR]