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Ancient Platycladus orientalis holds significant ecological, landscape, historical, and cultural value. In northern China, leaf blight has significantly impacted the growth and ornamental value of ancient P. orientalis. In this study, 26 blight leaf samples of ancient P. orientalis were collected in Beijing, China. Phylogenetic analysis based on the concatenated internal transcribed spacer (ITS), β-tubulin (tub2), and RNA polymerase second largest subunit (rpb2) DNA sequence data combined with fungal morphological characteristics revealed three taxa of Nothophoma, i.e. N. platycladus, N. spiraeae, and N. juglandis. Of which, N. platycladus is a species new to science. Koch's postulates indicated that all these three species of Nothophoma could cause leaf blight of P. orientalis. [ABSTRACT FROM AUTHOR]

The cause of peanut kernel shrivel (PKS) syndrome, affecting peanut crops in Australia's growing regions, is currently unknown. It is estimated that PKS is costing the peanut industry more than AUD 5 M p.a. and is a potential threat to the industry. Previous investigations have ruled out all abiotic factors and most biotic factors as the cause of PKS. This research aimed at investigating the scope, distribution, and cause of the PKS syndrome. The survey showed PKS symptoms to be present in peanut crops in all the growing regions surveyed. Based on our study of culturable microorganisms, there appears to be no clear-cut involvement of plant pathogenic bacteria and fungi; however, Fusarium spp. were revealed as the most prevalent fungi in affected plants. Moreover, the soil metagenomics study revealed Fusarium spp. as the most abundant fungal communities in the soil microbial profile, and they could contribute to the PKS syndrome. The consistent presence observed of the identified Fusarium oxysporum in PKS-affected samples could indicate a role for this pathogen in the syndrome, especially in conjunction with abiotic stressors. The pathogenicity testing of F. oxysporum resulted in very mild PKS symptoms. A separate report suggesting the involvement of phytoplasma in the PKS syndrome raises the possibility of an interplay of biotic factors in the development of this disease. Further investigation is warranted to determine the true cause or causes of this disease. [ABSTRACT FROM AUTHOR]

Abstract Background Cobweb disease is a fungal disease that commonly affects the cultivation and production of edible mushrooms, leading to serious yield and economic losses. It is considered a major fungal disease in the realm of edible mushrooms. The symptoms of cobweb disease were found during the cultivation of Lyophyllum decastes. This study aimed to identify the causative pathogen of cobweb disease and evaluate effective fungicides, providing valuable insights for field control and management of L. decastes cobweb disease. Results The causal agent of cobweb disease was isolated from samples infected and identified as Cladobotryum mycophilum based on morphological and cultural characteristics, as well as multi-locus phylogeny analysis (ITS, RPB1, RPB2, and TEF1-α). Pathogenicity tests further confirmed C. mycophilum as the responsible pathogen for this condition. Among the selected fungicides, Prochloraz-manganese chloride complex, Trifloxystrobin, tebuconazole, and Difenoconazole exhibited significant inhibitory effects on the pathogen’s mycelium, with EC50 values of 0.076 µg/mL, 0.173 µg/mL, and 0.364 µg/mL, respectively. These fungicides can serve as references for future field control of cobweb disease in L. decastes. Conclusion This study is the first report of C. mycophilum as the causing agent of cobweb disease in L. decastes in China. Notably, Prochloraz-manganese chloride complex demonstrated the strongest inhibitory efficacy against C. mycophilum.

Background: Cobweb disease is a fungal disease that commonly affects the cultivation and production of edible mushrooms, leading to serious yield and economic losses. It is considered a major fungal disease in the realm of edible mushrooms. The symptoms of cobweb disease were found during the cultivation of Lyophyllum decastes. This study aimed to identify the causative pathogen of cobweb disease and evaluate effective fungicides, providing valuable insights for field control and management of L. decastes cobweb disease. Results: The causal agent of cobweb disease was isolated from samples infected and identified as Cladobotryum mycophilum based on morphological and cultural characteristics, as well as multi-locus phylogeny analysis (ITS, RPB1, RPB2, and TEF1-α). Pathogenicity tests further confirmed C. mycophilum as the responsible pathogen for this condition. Among the selected fungicides, Prochloraz-manganese chloride complex, Trifloxystrobin, tebuconazole, and Difenoconazole exhibited significant inhibitory effects on the pathogen's mycelium, with EC50 values of 0.076 µg/mL, 0.173 µg/mL, and 0.364 µg/mL, respectively. These fungicides can serve as references for future field control of cobweb disease in L. decastes. Conclusion: This study is the first report of C. mycophilum as the causing agent of cobweb disease in L. decastes in China. Notably, Prochloraz-manganese chloride complex demonstrated the strongest inhibitory efficacy against C. mycophilum. [ABSTRACT FROM AUTHOR]

The germ theory states that pathogenic microorganisms are responsible for causing infectious diseases. The theory is inherently microbe-centric and does not account for variability in disease severity among individuals and asymptomatic carriership--two phenomena indicating an important role for host variability in infection outcome. The basic tenet of the germ theory was recently challenged, and a radically host-centric paradigm referred to as the "full-blown host theory" was proposed. According to this view, the pathogen is reduced to a passive environmental trigger, and the development of disease is instead due to pre-existing immunodeficiencies of the host. Here, we consider the factors that determine disease severity using established knowledge concerning evolutionary biology, microbial pathogenesis, and host-pathogen interactions. We note that the available data support a noncentric view that recognizes key roles for both the causative microbe and the host in dictating infection outcome. [ABSTRACT FROM AUTHOR]

México is among the main producers of onions, which are cultivated mainly in the states of Baja California, Chihuahua, Guanajuato, Michoacán, and Zacatecas. During June and November 2017, foliar blight symptoms were observed in commercial onion crops in the municipality of Copándaro, Michoacán. The incidence of the disease was 20% in June and 80% in November. The objective of this work was to identify the causal agent or agents of this disease. Fungal isolates recovered from symptomatic plants presented conidia typical of Alternaria and Stemphylium. Molecular identification and phylogenetic analysis using partial sequences of the nuclear ribosomal internal transcribed spacer (ITS) region, the translation elongation factor-1 alpha (TEF1), and RNA polymerase subunit II (RPB2) genes confirmed the identity of the isolates as species within the Alternaria alternata species complex, and Stemphylium vesicarium. The isolates reproduced foliar blight symptoms in inoculated onion plants in pathogenicity tests. This is the first report of Alternaria alternata sensu lato and Stemphylium vesicarium causing foliar blight in commercial onion crops in Michoacán. [ABSTRACT FROM AUTHOR]

Tsukamurella, a group of multi-drug resistant, Gram-positive, aerobic, and partially acid-fast bacteria, are emerging causes of bacterial conjunctivitis and keratitis. However, the pathogenesis of Tsukamurella keratitis is largely unknown. To address this, we used New Zealand White rabbits to develop the first eye infection model and conducted in vitro tests to study the pathogenesis mechanisms of Tsukamurella. There is increasing evidence that biofilms play a significant role in ocular infections, leading us to hypothesize that biofilm formation is crucial for effective Tsukamurella infection. In order to look for potential candidate genes which are important in biofilm formation and Tsukamurella keratitis. We performed genome sequencing of two ocular isolates, T. pulmonis-PW1004 and T. tyrosinosolvens-PW899, to identify potential virulence factors. Through in vitro and in vivo studies, we characterized their biological roles in mediating Tsukamurella keratitis. Our findings confirmed that Tsukamurella is an ocular pathogen by fulfilling Koch's postulates, and using genome sequence data, we identified tmytC, encoding a mycolyltransferase, as a crucial gene in biofilm formation and causing Tsukamurella keratitis in the rabbit model. This is the first report demonstrating the novel role of mycolyltransferase in causing ocular infections. Overall, our findings contribute to a better understanding of Tsukamurella pathogenesis and provide a potential target for treatment. Specific inhibitors targeting TmytC could serve as an effective treatment option for Tsukamurella infections.

Leaf-blight disease caused by the Fusarium oxysporum is an emerging problem in Dendrobium chrysotoxum production in China. Symptoms of leaf blight were observed on seedlings of D. chrysotoxum cultivated in a nursery in Ruili City, Yunnan Province, China. In this study, we isolated the Fusarium sp. associated with leaf-blight disease of D. chrysotoxum from the diseased seedlings. A pathogenicity test was performed to fulfill Koch's postulates to confirm the pathogenicity of isolated strains and identified using morphological and molecular techniques. The results revealed that all four isolated Fusarium sp. isolates (DHRL-01~04) produced typical blight symptoms followed by marginal necrosis of leaves on the D. chrysotoxum plants. On the PDA medium, the fungal colony appeared as a white to purplish color with cottony mycelium growth. Microconidia are oval-shaped, whereas macroconidia are sickle-shaped, tapering at both ends with 2–4 septations. The phylogenetic trees were construed based on internal transcribed spacer (ITS), translation elongation factor (EF-1α), and RNA polymerase subunit genes RPB1 and RPB2 genes, respectively, and blasted against the NCBI database for species confirmation. Based on the NCBI database's blast results, the isolates showed that more than 99% identify with Fusarium oxysporum. To our knowledge, this is the first comprehensive report on the identification of Fusarium oxysporum as the causal agent of Dendrobium chrysotoxum leaf blight in Yunnan Province, China, based on morphological and molecular characteristics. [ABSTRACT FROM AUTHOR]

In 2015 and 2016, two Barramundi (Lates calcarifer) farms in Singapore reported a disease outbreak characterized by lethargic behavior, pronounced inappetence, generalized skin lesions, erosions of the fins and tail, and ultimately high mortality in their fish. Next-generation sequencing and PCR confirmed presence of a novel virus belonging to the Alloherpesviridae family, Lates calcarifer herpesvirus (LCHV), which was subsequently isolated and cultured. We characterize, for the first time, the complete genome of two cultured LCHV isolates. The genome contains a long unique region of approximately 105,000 bp flanked by terminal repeats of approximately 24,800 bp, of which the first 8.2 kb do not show any similarity to described genomes in the Alloherpesviridae family. The two cultured isolates share 89% nucleotide identity, and their closest relatives are the viruses belonging to the genus Ictalurivirus. Experimental infections using one of the cultured LCHV isolates resulted in identical clinical signs as originally described in the index farm, both in intraperitoneal-injection infected fish and cohabitant fish, with mortality in both groups. Histopathological analysis showed pronounced abnormalities in the gills. Virus culture and PCR analysis confirmed the replication of LCHV in the infected fish, and thus Koch's postulates were fulfilled. [ABSTRACT FROM AUTHOR]

Background: Leaf spot disease severely impacts Ginkgo biloba (G. biloba) yield and quality. While microbial agents offer effective and non-toxic biological control for plant diseases, research on controlling leaf spot disease in G. biloba is notably scarce. Methods: The pathogenic fungi were isolated and purified from diseased and healthy leaves of G. biloba, Subsequent examinations included morphological observations and molecular identification via PCR techniques. A phylogenetic tree was constructed to facilitate the analysis of these pathogenic fungi, and Koch's postulates were subsequently employed to reaffirm their pathogenic nature. The antagonistic experiment was employed to select biocontrol bacteria, and subsequently, the isolated biocontrol bacteria and pathogenic fungi were inoculated onto healthy leaves to assess the inhibitory effects of the biocontrol bacteria. Results: Two pathologies responsible for the leaf spot disease on G. biloba were identified as Botryosphaeria dothidea and Neofusicoccum parvum via the analysis of phylogenetic tree and the application of Koch's Postulates. Additionally, we isolated two strains of biocontrol bacteria, namely Bacillus velezensis and Bacillus amyloliquefaciens. Their average inhibitory zones were measured at 4.78 cm and 3.46 cm, respectively. The inhibition zone of B. velezensis against N. parvum was 4 cm. B. velezensis showed a stronger inhibitory effect compared to B. amyloliquefaciens on the development of lesions caused by B. dothidea via leaf culture experiment. Conclusion: This research reports, for the first time, the presence of B. dothidea as a pathogenic fungus affecting G. biloba. Moreover, the biocontrol bacteria, B. velezensis and B. amyloliquefaciens, exhibited the capability to effectively inhibit the growth and reproduction of B. dothidea, indicating their promising potential as environmentally friendly biocontrol resources. [ABSTRACT FROM AUTHOR]

Tea (Camellia sinensis (L.) Kuntze) is one of the most important economic plants in China, and has many benefits for human health. Anthracnose is one of the most serious diseases of tea in China, and control of the fungus is important since most Chinese cultivars are susceptible to it. The agent of tea anthracnose was initially described as Gloeosporium theae-sinensis I. Miyake in Japan, which was later transferred to Discula, but this taxonomic position remains problematic. To shed light on these taxonomic and phylogenetic issues, the tea anthracnose pathogens were re-studied. Combining the morphological characteristics and a multigene phylogenetic analysis of nrITS, nrLSU, rpb2, and tef1 sequence data, a new genus Sinodiscula was proposed to accommodate the causal fungi of tea anthracnose, including a new species Sinodiscula camellicola and a new combination Sinodiscula theae-sinensis. Furthermore, the pathogenicity of the pathogens was determined according to Koch's postulates. This study thoroughly resolves the long-standing taxonomic and phylogenetic problems of the tea anthracnose pathogens. [ABSTRACT FROM AUTHOR]

Auricularia cornea is an important edible mushroom crop in China but the occurrence of cobweb disease has cause significance economic loss in its production. The rate of disease occurrence is 16.65% all over the country. In the present study, a new pathogen Hypomyces cornea sp. nov. was found to cause the cobweb disease. In July 2021, three strains of fungal pathogen were isolated from infected fruiting bodies and identified as H. cornea based on morphological studies and molecular phylogenetic analysis of internal transcribed spacer (ITS) of nuclear ribosomal DNA, mitochondrial large subunit (LSU) of rRNA and the partial translation elongation factor 1-alpha genes. The representative isolates of the pathogenic Hypomyces species used to perform pathogenicity test with spore suspension that caused similar symptoms as those observed in the cultivated field, and same pathogens could be re-isolated, which fulfill Koch's postulates. The typical biological characterization was examined of the serious pathogen to determine its favorable growth conditions, including suitable temperature, pH, carbon, nitrogen sources and light conditions. The findings revealed an optimum temperature of 25 °C, pH of 6, and soluble starch and peptone as the preferred carbon and nitrogen sources, respectively. The hyphal growth inhibition method was used for primary in vitro screening test of seven common fungicides, and the most suitable fungicide is Prochloraz manganese chloride complex, the EC 50 values of cobweb pathogen and mushrooms were 0.085 μg/mL and 2.452 μg/mL, respectively. The results of our research provide an evidence-based basis for the effective prevention and treatment of A. cornea cobweb disease. [ABSTRACT FROM AUTHOR]

Macrophomina phaseolina is a plant pathogenic fungus that is frequently described as having a broad host range encompassing more than 500 species. We noticed that citations provided in support of this statement do not actually demonstrate such a broad host range. To elucidate the true documented host range of this fungus, we initiated a literature metaanalysis of 894 publications on M. phaseolina since 1913. We discovered that the first host range summaries did not require Koch's postulates or other experimental demonstrations of pathogenicity. Most of the available early host claims were based on tenuous associations between the fungus and symptoms, sometimes without reporting isolation or morphological examination in vitro. These statements apparently led to a pattern of increasingly exaggerated host range claims, without support from a primary reference, until the claim that M. phaseolina has 500 hosts became common in the early 2000s. At present, the scientific community typically requires Koch's postulates to characterize pathogenicity on a new host. Among all the available literature, we only found primary experimental evidence for M. phaseolina's, pathogenicity on 97 hosts; 74 hosts confirmed by Koch's postulates and 23 hosts with all steps from Koch's postulates completed except for recovery of the pathogen from symptomatic tissues. This study demonstrates how scientific concepts can change over time and necessitate changes to historic axioms. We propose that the hyperbole surrounding the host range of M. phaseolina has obscured an accurate depiction of its biology. [ABSTRACT FROM AUTHOR]

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Pink staining in shiitake (Lentinula edodes (Berk.) Pegler) billets (Quercus griffithii Hook.f. and Thomson ex Miq.) causing the inhibition of shiitake mycelium and a reduction in shiitake production was observed throughout Bhutan in 2017–2018. Completion of Koch’s postulates confirmed the causal agent to be Scytalidium cuboideum, a first record of this disease in shiitake billets in Bhutan. In failed billets, it was observed that there was no growth of shiitake mycelium from the spawn. Trials suggest that S. cuboideum is responsible for the occurrences of poor colonisation by shiitake spawn—even when pink staining is not evident. Warm temperatures favour S. cuboideum, with shiitake able to sometimes overcome low rates of infection when incubated at low temperatures.

Pink staining in shiitake (Lentinula edodes (Berk.) Pegler) billets (Quercus griffithii Hook.f. and Thomson ex Miq.) causing the inhibition of shiitake mycelium and a reduction in shiitake production was observed throughout Bhutan in 2017-2018. Completion of Koch's postulates confirmed the causal agent to be Scytalidium cuboideum, a first record of this disease in shiitake billets in Bhutan. In failed billets, it was observed that there was no growth of shiitake mycelium from the spawn. Trials suggest that S. cuboideum is responsible for the occurrences of poor colonisation by shiitake spawn--even when pink staining is not evident. Warm temperatures favour S. cuboideum, with shiitake able to sometimes overcome low rates of infection when incubated at low temperatures. [ABSTRACT FROM AUTHOR]

Grapevine leafroll disease (GLRD) is the most globally prevalent and destructive disease complex responsible for significant reductions in grape yield and quality as well as wine production. GLRD is associated with several positive-strand RNA viruses of the family Closteroviridae, designated as grapevine leafroll-associated viruses (GLRaVs). However, the specific etiological role of any of these GLRaVs in GLRD has not been demonstrated. Even though GLRaV-3 is considered the chief GLRD agent, little is known about the molecular, cellular, and pathological properties of this virus. Such a knowledge gap is due to multiple factors, including the unavailability of biologically active virus cDNA clones and the lack of reliable experimental systems for launching grapevine infection using such clones. In this work, we tested four methods for inoculating tissue-cultured grapevine plantlets with cDNA clones of GLRaV-3: (i) vacuum agro-infiltration; (ii) agro-pricking; (iii) agro-drenching; and (iv) agro-injection. We showed that vacuum agro-infiltration was the most effective of these methods. Furthermore, we examined the impacts of different experimental conditions on the survival and infectivity rate of grapevines after infiltration. To verify the infectivity rate for different treatments, we used RT-PCR, RT-qPCR, and Western blotting. We found that humidity plays a critical role in the survival of plantlets after agro-infiltration and that the use of RNA silencing suppressor and dormancy treatment both had strong effects on the infection rates. To our knowledge, the experimental protocol reported herein is the most effective system for launching the infection of grapevine using cDNA clones of grapevine viruses featuring up to a 70% infection rate. This system has strong potential to facilitate grapevine virology research including the fulfillment of Koch's postulates for GLRD and other major virus diseases as well as identifying the molecular, cellular, and pathological properties of GLRaVs and, potentially, other important grapevine viruses. [ABSTRACT FROM AUTHOR]

This study aimed to identify fungal species associated with trunk diseases of sweet cherries (Prunus avium) in several commercial cherry orchards in Beijing, Guizhou and Shandong provinces, China. In total, eighteen fungal strains that fitted well into the species concept of Diaporthe were isolated. Based on both morphological and multi-locus phylogenetic analyses of internal transcribed spacer region (ITS), beta-tubulin (tub-2), calmodulin (Cal) and translation elongation factor 1-α (tef1–α) sequencing data, fourteen isolates were identified as Diaporthe eres, while four isolates were classified as D. hongkongensis. Here, we report D. hongkongensis causing sweet cherry branch dieback disease and, further, we confirmed the host association of D. eres with sweet cherries in China. A pathogenicity assay revealed the ability of both D. eres and D. hongkongensis to cause shoot necrosis and stem lesions on Prunus avium cv. 'Brooks' (mean lesion lengths of 1.86 cm and 1.56 cm, respectively). The optimal temperature for the growth of both Diaporthe species was tested. The optimal growth temperature for D. hongkongensis was 30 °C, and the 25–28 °C temperatures were the most favorable for the growth of D. eres strains. This research advances the understanding of fungal trunk diseases in fruit crops, particularly gummosis and branch dieback disease in Chinese cherry orchards, and will aid growers in making decisions about cultural practices and disease management. [ABSTRACT FROM AUTHOR]

Abstract Background For more than a century, the Koch’s postulates have been the golden rule for determining the causative agents in diseases. However, in cases of multiple pathogens-one disease, in which different pathogens can cause the same disease, the selection of microorganisms that regress infection is hard when Koch’s postulates are applied. Microbiome approaches can obtain relatively complete information about disease-related microorganisms and can guide the selection of target microorganisms for regression infection. In the present study, whitish muscle syndrome (WMS) of Scylla paramamosain, which has typical symptoms with whitish muscle and blackened hemolymph was used as an example to establish a new research strategy that integrates microbiome approaches and Koch’s postulates to determinate causative agents of multiple pathogens-one disease. Results Microbiome results revealed that Aeromonas, Acinetobacter, Shewanella, Chryseomicrobium, Exiguobacterium, Vibrio and Flavobacterium, and Kurtzmaniella in hemolymph were bacterial and fungal indicators for WMS. A total of 23 bacteria and 14 fungi were isolated from hemolymph and muscle tissues, and among the bacteria, Shewanella chilikensis, S. xiamenensis, Vibrio alginolyticus, S. putrefaciens, V. fluvialis, and V. parahaemolyticus were present in hemolymph and/or muscle tissues in each WMS crab, and the last three species were also present in three Healthy crabs. The target bacteria and fungi were further screened to regression infections based on two criteria: whether they belonged to the indicator genera for WMS, whether they were isolated from both hemolymph and muscle tissues in most WMS crabs. Only S. chilikensis, S. putrefaciens, S. xiamenensis, V. alginolyticus, V. fluvialis, and V. parahaemolyticus met both two criteria. The six bacteria that met both two criteria and six fungi and another bacterium that unmatched any of two criteria were used to perform regression infection experiments based on Koch’s postulates. S. chilikensis, S. putrefaciens, S. xiamenensis, V. alginolyticus, V. fluvialis, and V. parahaemolyticus met both two criteria, and the results indicate that they cause WMS in crabs independently. Conclusions This study fully demonstrated that our research strategy that integrates the microbiome and Koch’s postulates can maximize the ability to catch pathogens in one net for the situation of multiple pathogens-one disease. Video Abstract

The cause of peanut kernel shrivel (PKS) syndrome, affecting peanut crops in Australia’s growing regions, is currently unknown. It is estimated that PKS is costing the peanut industry more than AUD 5 M p.a. and is a potential threat to the industry. Previous investigations have ruled out all abiotic factors and most biotic factors as the cause of PKS. This research aimed at investigating the scope, distribution, and cause of the PKS syndrome. The survey showed PKS symptoms to be present in peanut crops in all the growing regions surveyed. Based on our study of culturable microorganisms, there appears to be no clear-cut involvement of plant pathogenic bacteria and fungi; however, Fusarium spp. were revealed as the most prevalent fungi in affected plants. Moreover, the soil metagenomics study revealed Fusarium spp. as the most abundant fungal communities in the soil microbial profile, and they could contribute to the PKS syndrome. The consistent presence observed of the identified Fusarium oxysporum in PKS-affected samples could indicate a role for this pathogen in the syndrome, especially in conjunction with abiotic stressors. The pathogenicity testing of F. oxysporum resulted in very mild PKS symptoms. A separate report suggesting the involvement of phytoplasma in the PKS syndrome raises the possibility of an interplay of biotic factors in the development of this disease. Further investigation is warranted to determine the true cause or causes of this disease.

Summary: Fusarium wilt is the major biotic constraint responsible for substantial loss in the agricultural production and yield of safflower (Carthamus tinctorius L.). To better understand the symptomatology and etiology of wilt disease, safflower-growing fields of Karnataka and Maharashtra states in India were surveyed. The infected plants exhibited characteristic symptoms of wilt disease including browning of stem, chlorosis, and drooping of leaves. Fungal isolates obtained from infected parts of plants were morphologically characterized. Along with Fusarium oxysporum, another species of Fusarium was identified. This species produced buff to dark red colonies with aerial mycelia. Microconidia were clavate with a flattened base, aseptate, and 5.2–5.9 × 1.5–2.0 μm in size. Macroconidia were falcate to subfalcate, 3–5 septate, and 21.1–38.0 × 1.9–2.7 μm in size. Using internal transcribed spacer (ITS) of rDNA and translation elongation factor-1α (TEF-1α) genes, the identity of this species was confirmed as Fusarium proliferatum (Fp). Molecular phylogeny was inferred for all Fp isolates using ITS and TEF-1a sequences and they displayed close relatedness to Fp type material. The adult plants of susceptible cultivar of safflower (cv. Manjira) were inoculated with Fp spore suspension wherein the wilt disease was recapitulated. Morphologically identical Fp was isolated from the infected plants fulfilling Koch's postulates. This is a new record of wilt disease inflicted by Fp on safflower-growing fields of India. [ABSTRACT FROM AUTHOR]

Background: For more than a century, the Koch's postulates have been the golden rule for determining the causative agents in diseases. However, in cases of multiple pathogens-one disease, in which different pathogens can cause the same disease, the selection of microorganisms that regress infection is hard when Koch's postulates are applied. Microbiome approaches can obtain relatively complete information about disease-related microorganisms and can guide the selection of target microorganisms for regression infection. In the present study, whitish muscle syndrome (WMS) of Scylla paramamosain, which has typical symptoms with whitish muscle and blackened hemolymph was used as an example to establish a new research strategy that integrates microbiome approaches and Koch's postulates to determinate causative agents of multiple pathogens-one disease. Results: Microbiome results revealed that Aeromonas, Acinetobacter, Shewanella, Chryseomicrobium, Exiguobacterium, Vibrio and Flavobacterium, and Kurtzmaniella in hemolymph were bacterial and fungal indicators for WMS. A total of 23 bacteria and 14 fungi were isolated from hemolymph and muscle tissues, and among the bacteria, Shewanella chilikensis, S. xiamenensis, Vibrio alginolyticus, S. putrefaciens, V. fluvialis, and V. parahaemolyticus were present in hemolymph and/or muscle tissues in each WMS crab, and the last three species were also present in three Healthy crabs. The target bacteria and fungi were further screened to regression infections based on two criteria: whether they belonged to the indicator genera for WMS, whether they were isolated from both hemolymph and muscle tissues in most WMS crabs. Only S. chilikensis, S. putrefaciens, S. xiamenensis, V. alginolyticus, V. fluvialis, and V. parahaemolyticus met both two criteria. The six bacteria that met both two criteria and six fungi and another bacterium that unmatched any of two criteria were used to perform regression infection experiments based on Koch's postulates. S. chilikensis, S. putrefaciens, S. xiamenensis, V. alginolyticus, V. fluvialis, and V. parahaemolyticus met both two criteria, and the results indicate that they cause WMS in crabs independently. Conclusions: This study fully demonstrated that our research strategy that integrates the microbiome and Koch's postulates can maximize the ability to catch pathogens in one net for the situation of multiple pathogens-one disease. EgKJnBsvf5xgzELdpRDt_Q Video Abstract [ABSTRACT FROM AUTHOR]

Aquatic diseases can have serious impacts on global biodiversity, economies, and societies. Understanding the cause of emerging aquatic diseases is a scientific challenge and governmental priority to reduce impacts and inform discovery of new treatments and management methods. We propose a holistic approach leveraging medical criteria and traditional and modern technologies to demonstrate causal factors associated with emerging diseases of aquatic organisms. Technological developments can increasingly enable disease emergence forecasting, high-throughput screening to rapidly shortlist suspect infectious and noninfectious agents, culture of a broader range of aquatic microorganisms, and challenge trials with whole organisms and surrogate models. Resolving the cause of disease (= aetiology) in aquatic organisms is a challenging but essential goal, heightened by increasing disease prevalence in a changing climate and an interconnected world of anthropogenic pathogen spread. Emerging diseases play important roles in evolutionary ecology, wildlife conservation, the seafood industry, recreation, cultural practices, and human health. As we emerge from a global pandemic of zoonotic origin, we must focus on timely diagnosis to confirm aetiology and enable response to diseases in aquatic ecosystems. Those systems' resilience, and our own sustainable use of seafood, depend on it. Synchronising traditional and recent advances in microbiology that span ecological, veterinary, and medical fields will enable definitive assignment of risk factors and causal agents for better biosecurity management and healthier aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Leaf-blight disease caused by the Fusarium oxysporum is an emerging problem in Dendrobium chrysotoxum production in China. Symptoms of leaf blight were observed on seedlings of D. chrysotoxum cultivated in a nursery in Ruili City, Yunnan Province, China. In this study, we isolated the Fusarium sp. associated with leaf-blight disease of D. chrysotoxum from the diseased seedlings. A pathogenicity test was performed to fulfill Koch’s postulates to confirm the pathogenicity of isolated strains and identified using morphological and molecular techniques. The results revealed that all four isolated Fusarium sp. isolates (DHRL-01~04) produced typical blight symptoms followed by marginal necrosis of leaves on the D. chrysotoxum plants. On the PDA medium, the fungal colony appeared as a white to purplish color with cottony mycelium growth. Microconidia are oval-shaped, whereas macroconidia are sickle-shaped, tapering at both ends with 2–4 septations. The phylogenetic trees were construed based on internal transcribed spacer (ITS), translation elongation factor (EF-1α), and RNA polymerase subunit genes RPB1 and RPB2 genes, respectively, and blasted against the NCBI database for species confirmation. Based on the NCBI database’s blast results, the isolates showed that more than 99% identify with Fusarium oxysporum. To our knowledge, this is the first comprehensive report on the identification of Fusarium oxysporum as the causal agent of Dendrobium chrysotoxum leaf blight in Yunnan Province, China, based on morphological and molecular characteristics.

Tea (Camellia sinensis (L.) Kuntze) is one of the most important economic plants in China, and has many benefits for human health. Anthracnose is one of the most serious diseases of tea in China, and control of the fungus is important since most Chinese cultivars are susceptible to it. The agent of tea anthracnose was initially described as Gloeosporium theae-sinensis I. Miyake in Japan, which was later transferred to Discula, but this taxonomic position remains problematic. To shed light on these taxonomic and phylogenetic issues, the tea anthracnose pathogens were re-studied. Combining the morphological characteristics and a multigene phylogenetic analysis of nrITS, nrLSU, rpb2, and tef1 sequence data, a new genus Sinodiscula was proposed to accommodate the causal fungi of tea anthracnose, including a new species Sinodiscula camellicola and a new combination Sinodiscula theae-sinensis. Furthermore, the pathogenicity of the pathogens was determined according to Koch’s postulates. This study thoroughly resolves the long-standing taxonomic and phylogenetic problems of the tea anthracnose pathogens.

Symptoms of foliar blight were observed on turfgrass in Oran (Algeria), including yellow chlorotic patches on leaves during the 2020 summer (temperatures between 35 and 40°C). Symptoms extended downward from leaf tips and entire leaves became blighted, leading to irregular discoloured areas that later turned brown. Isolations from infected plants included 214 isolates identified as Curvularia or Bipolaris, based on morphological traits. Other isolates included Fusarium, Myrothecium and Acremonium spp. Three molecular loci, ITS rDNA, gpd and tef1, were amplified and sequenced. Morphological and multi-locus phylogenetic analyses revealed four fungal species viz. B. sorokiniana, C. spicifera, C. verruculosa, C. geniculata, and two additional Curvularia lineages, some of these fungi are reported are first records for Algeria. Koch's postulates were confirmed by inoculating potted turfgrass with spore suspensions of 16 isolates and re-isolating of the inoculated pathogens from symptomatic tissues. Bipolaris sorokiniana was the most virulent pathogen causing numerous foliar necrotic lesions similar to those observed in the field. Other isolates infected basal leaves only, and caused less severe symptoms. The results show that Curvularia species may be secondary pathogens infecting stressed plants, and that simultaneous occurrence of high temperatures and poor water quality have influenced disease progression. Correct identification of these pathogens is important for applying appropriate and timely disease management. [ABSTRACT FROM AUTHOR]

Phoenix dactylifera L. (Date palm) is one of the leading perennial fruit crops regarding its nutritional profile, medicinal significance, excellent yields, long life, and high adaptability to diverse climatic conditions of semi-arid and arid regions globally. Eleven major palm-growing districts of Punjab, Sindh, and Khyber Pakhtunkhwa were surveyed for wilt disease assessment on date palms. The date palm plantation was highly affected with Fusarium wilt diseases with 55%, the incidence in Khairpur (Sindh province), followed by Bahawalpur at 47.4% (Punjab Province) and 45% in Dera Ismail Khan (KPK province). Disease severity was recorded as 65% in Khairpur, 55% in Bahawalpur, and 50% in Dera Ismail Khan (Sindh, Punjab, and KPK, respectively). Sixty-three Fusarium isolates were obtained from three hundred and eighty (380) diseased samples, and thirty isolates randomly selected out of 63 were studied for morpho-cultural and microscopic characterization. Morpho-cultural characters, i.e., colony pigmentation, growth pattern, conidia (macro and microconidia), shape, apical cell shape, and phalidies studied, coinciding with typical characteristics of Fusarium oxysporum. Twenty isolates of the Fusarium population were subjected to the ITS region sequence data-based phylogenetic network. The Neighbor net algorithm computed an unrooted phylogenetic network displayed as four branched genetic network that depicted the division of twenty fungal isolates into four groups. F. oxysporum (FMB-FO-PD-011) inoculated onto healthy symptomless detached date palm leaves, seedlings, and suckers under controlled and field conditions showed typical wilt disease symptoms. Hence this study proved that F. oxysporum is the potential cause of date palm wilt in Pakistan. [ABSTRACT FROM AUTHOR]

White mold of cabbage caused by Sclerotinia sclerotiorum was identified in Bangladesh Agricultural Research Institute (BARI), Bangladesh. The fungus was isolated from the symptomatic leaves of cabbage on potato dextrose agar (PDA) medium. Subsequent inoculation of S. sclerotiorum on detached cabbage leaves and cabbage heads confirmed the pathogenicity of fungus. Based on morphological characteristics and phylogenetic analysis, the pathogen was identified as Sclerotinia sclerotiorum. [ABSTRACT FROM AUTHOR]

【Objective】Since 2017, an anthracnose was extensively occurred on P. cyrtonema in the Hunan province of China. The present paper aimed to clarify the pathogen and the sensitivity of the pathogen to fungicides.【Method】The pathogen fungal stains were isolated from symptomatic leaves and identified by both morphological and molecular tools using both the ITS, ACT, CHS-1 and GPDH gene regions. Pathogenicity was confirmed with inoculation experiments that fulfilled the Koch's postulates. On this basis, the indoor toxicity of 5 fungicides to the pathogen was determined by mycelial growth rate method.【Result】By tissue isolation, 16 morphologically identical strains were isolated from the diseased diseased leaves of four plantation in Hunan province, and the colony morphology and culture characteristics of the strains were observed to confirm that they were Colletotrichum sp.. Molecular identification of CLHJY4-3 determined that the pathogen was C. spaethianum. The pathogenicity was confirmed by inoculation and the Koch's postulates was verified. The average growth rate of the hyphae of this pathogen was 1.1 cm/day. Conidia were 18.4 to 25.0 μm long and 3.9 to 5.3 μm wide. The seta were dark brown, with 2-3 septs, 79-107 μm long. The results of indoor toxicity determination showed that among the five agents, prochloraz had the strongest inhibitory effect on hyphal growth, EC50 was 0.031 μg/mL, followed by pyraclostrobin and tebuconazole, with the EC50 of 0.049 and 0.252 μg/mL, respectively. The inhibitory effects of thiophanate-methyl and carbendazim were relatively poor, with the EC50 of 2.911 and 1.763 μg/mL, respectively. 【Conclusion】C. spaethianum was the pathogen of leaf spot of P. cyrtonema in Hunan province. Moreover, prochloraz and pyraclostrobin were screened as better fungicides against the pathogen fungus. [ABSTRACT FROM AUTHOR]

The German anatomist and pathologist Jakob Henle's essay on miasma and miasmatic-contagious diseases is considered a medical classic. Nevertheless, it has rarely been analyzed in depth. If at all, it has been read as foreshadowing Robert Koch's "postulates," the famous set of criteria for identifying pathogens. This reading has created misunderstandings of Henle's own work on miasma and miasmatic-contagious diseases and impeded our understanding of the broader experimental tradition on which later nineteenth-century medical research was grounded. I place Henle's work in the context of early nineteenth-century research on infectious diseases and disease causation. Moreover, I show how it resonates with experimental research on invisible causal agents in other fields, including chemistry, pharmacology, physiology, veterinary science, and natural history. The strategies encapsulated in Koch's "postulates" were commonly used in these fields; Koch and Henle were both part of a broader experimental tradition that was well established in the early 1800s. [ABSTRACT FROM AUTHOR]

In Bazhong City, Sichuan Province, China, top dieback symptoms were found on many pine trees (Pinus thunbergii Parl). The tips of old needles first turned grayish-green and then developed into brown bands in the field. Phylogenetic analysis of concatenated ITS and EF1-α indicated the pathogen of this dieback disease as Diplodia neojuniperi. Additionally, effects of temperature, pH and medium on the mycelial growth were also characterized. The most favorable temperature and pH level for mycelial growth are 25°C and 8, respectively. The optimal medium for mycelial growth is PDA medium. To our knowledge, this is the first report of D. neojuniperi causes Diplodia top dieback on Pinus thunbergii. Our results provide fundamental information for monitoring and preventing such disease in the future. [ABSTRACT FROM AUTHOR]

Botrytis cinerea infects more than 1400 plant species globally, resulting in severe damage pre- and post-harvest. This study aimed to isolate and identify B. cinerea from tomato plants from local greenhouses and assess the inhibitory capacities of local Bacillus strains against B. cinerea. Various B. cinerea strains isolated from infected tomato plants exhibited characteristic symptoms. The ITS sequences and phylogenetic analysis of isolates exhibited 99 % homology with B. cinerea. Pathogenicity tests on healthy tomato vegetative growth or detached leaves using QB13, QBuk1, and QUna fungal isolates fulfilled Koch's postulates. Symptomatic characteristics resulting from the artificial inoculations of tomato grey mould closely resembled those of the original diseased leaves and stems collected from the field after 7 DPI when seven strains of Bacillus subtilis (64C1, 88D, 65D, 64C2, 41D1, 23A2, and 102) tested in-vitro against B. cinerea demonstrated that all of Bacillus subtilis isolates displayed notably strong antagonistic effects against B. cinerea. Mycelial growth inhibition ranged from 37 % (isolate 65D) to 60 % (isolate 102) compared to the untreated control. The most substantial inhibitory effects against B. cinerea were statistically observed with isolates 88D and 102, which exhibited inhibition rates of 58 % and 60 %, respectively. Morphological and molecular identification and pathogenicity analysis revealed that all 20 B. cinerea isolates obtained from infected tomato plants from greenhouses exhibited a highly pathogenic effect on tomato plants. This study states the basis for developing natural biocontrol agents to combat grey mould caused by B. cinerea on tomato plants. • Botrytis cinerea isolates obtained from tomato were identified based on the morphological characteristics and phylogenetic analysis of the ITS region. • All 20 B. cinerea isolates obtained from infected tomato were highly pathogenic on tomato. • Bacillus subtilis isolates revealed strong antagonistic effects against B. cinerea. [ABSTRACT FROM AUTHOR]

This study aimed to identify fungal species associated with trunk diseases of sweet cherries (Prunus avium) in several commercial cherry orchards in Beijing, Guizhou and Shandong provinces, China. In total, eighteen fungal strains that fitted well into the species concept of Diaporthe were isolated. Based on both morphological and multi-locus phylogenetic analyses of internal transcribed spacer region (ITS), beta-tubulin (tub-2), calmodulin (Cal) and translation elongation factor 1-α (tef1–α) sequencing data, fourteen isolates were identified as Diaporthe eres, while four isolates were classified as D. hongkongensis. Here, we report D. hongkongensis causing sweet cherry branch dieback disease and, further, we confirmed the host association of D. eres with sweet cherries in China. A pathogenicity assay revealed the ability of both D. eres and D. hongkongensis to cause shoot necrosis and stem lesions on Prunus avium cv. ‘Brooks’ (mean lesion lengths of 1.86 cm and 1.56 cm, respectively). The optimal temperature for the growth of both Diaporthe species was tested. The optimal growth temperature for D. hongkongensis was 30 °C, and the 25–28 °C temperatures were the most favorable for the growth of D. eres strains. This research advances the understanding of fungal trunk diseases in fruit crops, particularly gummosis and branch dieback disease in Chinese cherry orchards, and will aid growers in making decisions about cultural practices and disease management.

Inflammatory bowel disease (IBD) is a chronic non-specific inflammatory disease that occurs in the intestinal tract. It is mainly divided into two subtypes, i.e., the Crohn’s disease (CD) and ulcerative colitis (UC). At present, its pathogenesis has not been fully elucidated, but it has been generally believed that the environment, immune disorders, genetic susceptibility, and intestinal microbes are the main factors for the disease pathogenesis. With the development of the sequencing technology, microbial factors have received more and more attention. The gut microbiota is in a state of precise balance with the host, in which the host immune system is tolerant to immunogenic antigens produced by gut commensal microbes. In IBD patients, changes in the balance between pathogenic microorganisms and commensal microbes lead to changes in the composition and diversity of gut microbes, and the balance between microorganisms and the host would be disrupted. This new state is defined as dysbiosis. It has been confirmed, in both clinical and experimental settings, that dysbiosis plays an important role in the occurrence and development of IBD, but the causal relationship between dysbiosis and inflammation has not been elucidated. On the other hand, as a classic research method for pathogen identification, the Koch’s postulates sets the standard for verifying the role of pathogens in disease. With the further acknowledgment of the disease pathogenesis, it is realized that the traditional Koch’s postulates is not applicable to the etiology research (determination) of infectious diseases. Thus, many researchers have carried out more comprehensive and complex elaboration of Koch’s postulates to help people better understand and explain disease pathogenesis through the improved Koch’s postulates. Therefore, focusing on the new perspective of the improved Koch’s postulates is of great significance for deeply understanding the relationship between dysbiosis and IBD. This article has reviewed the studies on dysbiosis in IBD, the use of microbial agents in the treatment of IBD, and their relationship to the modified Koch’s postulates.

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by the production of diagnostic antimitochondrial antibodies (AMA) reactive to the pyruvate dehydrogenase complex. A human betaretrovirus (HBRV) resembling mouse mammary tumor virus has been characterized in patients with PBC. However, linking the viral infection with the disease is not a straight-forward process because PBC is a complex multifactorial disease influenced by genetic, hormonal, autoimmune, environmental, and other factors. Currently, PBC is assumed to have an autoimmune etiology, but the evidence is lacking to support this conjecture. In this review, we describe different approaches connecting HBRV with PBC. Initially, we used co-cultivation of HBRV with biliary epithelial cells to trigger the PBC-specific phenotype with cell surface expression of cryptic mitochondrial autoantigens linked with antimitochondrial antibody expression. Subsequently, we have derived layers of proof to support the role of betaretrovirus infection in mouse models of autoimmune biliary disease with spontaneous AMA production and in patients with PBC. Using Hill's criteria, we provide an overview of how betaretrovirus infection may trigger autoimmunity and propagate biliary disease. Ultimately, the demonstration that disease can be cured with antiviral therapy may sway the argument toward an infectious disease etiology in an analogous fashion that was used to link H. pylori with peptic ulcer disease. [ABSTRACT FROM AUTHOR]

El encrespamiento amarillo (EA), la enfermedad más severa detectada en Argentina, causa síntomas y daños en cultivos de batata en toda la región productora. Desde 2010/11 se ha detectado la presencia de cuatro virus en plantas sintomáticas del cv. Arapey INIA recolectadas en lotes de Colonia Caroya, provincia de Córdoba. Los virus son sweet potato feathery mottle virus (SPFMV) y sweet potato virus G (SPVG), dos potyvirus transmitidos de forma no persistente por Myzus persicae; un closterovirus: sweet potato chlorotic stunt virus (SPCSV) y un geminivirus: sweet potato leaf curl virus (SPLCV), ambos transmitidos por Bemisia tacabi de manera semipersistente y persistente, respectivamente. Los objetivos de este trabajo fueron aislar e identificar el o los virus involucrados en la enfermedad EA de la batata y determinar la combinación de virus que reproduce la sintomatología de EA Solo la combinación de los cuatro virus permitió reproducir la sintomatología más severa del encrespamiento amarillo observada a campo en dicho genotipo. Los síntomas incluyen clorosis, achaparramiento, mosaico, ampollado, enrulado de la hoja, manchas cloróticas, diseños cloróticos, reducción y distorsión del área foliar, bordes de la hoja curvados hacia arriba. La presencia de cada uno de los virus se detectó mediante pruebas serológicas (DAS, NCM y TAS-ELISA) y moleculares (PCR). Se concluye que la interacción de SPFMV, SPVG, SPCSV y SPLCV es necesaria para el desarrollo de EA. [ABSTRACT FROM AUTHOR]

Rosa roxburghii Tratt is a rosaceous shrub originating from southwest China (Fu et al. 2020). From September to October 2022, R. roxburghii rot occurred in Guizhou Province, China, within a major R. roxburghii production area covering from 5 ha to 50 ha, with an incidence rate of 10 to 15%. Symptoms manifested as black and brown lesions on the fruit surface, which were concave, soft, foul-smelling, and surrounded by grayish-brown tissue. Three infected R. roxburghii shrubs were randomly collected from each household, placed in transparent plastic bags, and pathogen isolation was conducted in a laboratory. Infected R. roxburghii fruits were surface-sterilized with 0.5% NaOCl for 2 min, rinsed five times with sterile water, and dried. Symptomatic tissues from the margin between necrotic and healthy tissues were cut into 5 × 5 mm pieces, placed onto potato dextrose agar (PDA), and incubated at 28ºC in the dark for 5 days. Hyphal tips of fungi growing from the samples were transferred onto new PDA plates and incubated until they produced conidia. A total of five fungal isolates with similar morphological characteristics were obtained. The colony obtained by single-spore purification was light purple to dark purple with abundant aerial mycelium. Macroconidia were relatively slender with a curve and zero to three septate. Microconidia appeared obovoid to pyriform, with sizes of 5.2 to 17.2 × 2.1 to 3.3 μm (n = 50). The morphological characteristics were consistent with Fusarium annulatum (Yilmaz et al. 2021). Genomic DNA of two representative isolates (Zhaochanglin 1621 and 1622) was extracted using the DN14 cetyltrimethylammonium bromide rapid plant genome extraction kit (Aidlab Biotechnologies Co., Ltd, Beijing). The TEF1 and RPB2 gene were amplified by Polymerase Chain Reaction using primers EF1-983F/EF1-2218R (Rehner et al, 2005), bRPB2-6F/bRPB2-7.1R (Matheny et al, 2002), respectively. All sequences were deposited in GenBank (TEF1, PP236860, PP236861; RPB2, PP767864, PP767865). BLAST searches of the TEF1, and RPB2 sequences revealed the TEF1 sequences had 99.89% (937/938 bp) identity with F. annulatum isolate CBS 258.54; and the RPB2 sequences had 99.86% (737/738 bp) identity to isolate CBS 267.93. In the phylogenetic tree, the isolates (Zhaochanglin 1621 and 1622) clustered with the representative strains of F. annulatum. The morphology and multi-gene phylogenetic analysis indicated that is the isolates were F. annulatum. To complete Koch's postulates, five mature, healthy R. roxburghii fruits were surface disinfected with 1% NaClO solution for 1 min, rinsed with sterile water, and dried at 25℃ for 30 min. A conidial suspension (106 spores/ml) collected from two isolates (Zhaochanglin 1621 and 1622) was sprayed onto R. roxburghii fruits, and the control treatments were sprayed with sterile distilled water. All R. roxburghii fruits were incubated at 25 ºC with 80% relative humidity. The experiment had five replicates. After 7 days of incubation, all the inoculated fruits showed similar symptoms to those initially observed on the originally infected plants. The same pathogen was reisolated and identified by morphological character ization and molecular analysis, fulfilling Koch's postulates. Thus, the pathogen causing rot of R. roxburghii was determined to be F. annulatum (H. Zhang et al, 2024). To our knowledge, this is the first report of F. annulatum causing R. roxburghii rot disease in China. F.annulatum has a wide range of hosts and has been reported to infect a wide range of crops, fruits, and vegetables (Bacon and Nelson 1994). This study lays a foundation for further study and developing disease control methods and the improvement of the economic benefits of R. roxburghii.

We argue that Koch's postulates are best understood within an interventionist account of causation, in the sense described in Woodward (2003). We show how this treatment helps to resolve interpretive puzzles associated with Koch's work and how it clarifies the different roles the postulates play in providing useful, yet not universal criteria for disease causation. Our paper is an effort at rational reconstruction; we attempt to show how Koch's postulates and reasoning make sense and are normatively justified within an interventionist framework and more difficult to understand within alternative frameworks for thinking about causation.

Abstract Pennisetum plants (Pennisetum alopecuroides L.), displaying a dwarfing phenotype along with delayed flowering and mosaic symptom on leaves, were found in Beijing, China. Flexuous filamentous particles with a size of approximate 15 × 850 nm were observed in symptomatic leaves via transmission electron microscopy. Deep sequencing of small RNAs (sRNA) from symptomatic leaves and analysis of sRNA populations were then conducted to determine the genome sequence of the viral agent in diseased plant tissues. It showed that the viral agent had one positive-sense and single-stranded RNA genome, which consisted of 9717 nucleotides (nts) excluding poly(A) tail. The complete viral genome contained a large open reading frame, encoding a polyprotein of 3131 amino acids (aa). Sequence comparison and phylogenetic analysis demonstrated that the viral agent belonged to the genus Potyvirus in the family Potyviridae. In the cladogram it was most closely related to johnsongrass mosaic virus, sharing 72% nt and 65% aa sequence identity. This viral agent was provisionally named pennisetum alopecuroides mosaic virus (PalMV). Subsequently, it was confirmed that PalMV is the causal agent of this new disease in P. alopecuroides by Koch’s postulates and reverse transcription-polymerase chain reaction analysis. Moreover, maize, millet, wheat, sorghum and rice plants were experimentally infected by PalMV via rub inoculation. Consequently, we proposed that PalMV could be a potentially dangerous virus threating a wide range of cereal crops.

During the field surveys in Jiangsu Province, China, contiguous patches of rice plants with varying degrees of dwarfing, wax-white or dark brown enations at the base of stems, and abnormal heading symptoms were observed in the fields located in Jiangning District in Nanjing City, Jurong County in Zhenjiang City, and Zhangjiagang County in Suzhou City. Through molecular analyses, the presence of southern rice black-streaked dwarf virus was confirmed in symptomatic rice plants. The infections of other rice viruses that cause dwarfing were also ruled out. Additionally, Koch's postulates were fulfilled, further validating SRBSDV as the causal agent for the observed dwarfing disease epidemic. Furthermore, the phylogenetic analyses revealed that the SRBSDV prevalent in Jiangsu in 2023 may originate from multiple regions in Vietnam. Our study has documented the emergence of an SRBSDV epidemic in Jiangsu in 2023, marking the first incidence of southern rice black-streaked dwarf disease in this region. • Documented the first SRBSDV epidemic in Jiangsu, China, marking a significant geographic expansion of this disease. • The SRBSDV epidemic in Jiangsu involves both primary and secondary infections. • SRBSDV strains in Jiangsu in 2023 may have multiple origins in Vietnam. • Highlighted the crucial need for monitoring and managing SRBSDV to ensure food security in Jiangsu Province. [ABSTRACT FROM AUTHOR]

A search in PubMed/Medline showed that research in the HIV virus has not yet been shown to honour Koch's four postulates regarding HIV as a cause for AIDS. In this article we suggest an alternative model for AIDS based on classical psychosomatic theory and the State-of-Life Theory, which gives a general description of the quality of human life based on a number of central existential factors. The State-of-Life Theory explains the development of reduced immunological resistance, from modest and temporary to the dramatic, permanently reduced immunological resistance, which is identical with clinical AIDS. The theoretical framework points to the following dimensions as crucial for treatment success: 1. Human consciousness, which is the causal layer: a. Beliefs related to health. b. Beliefs related to Self. c. Beliefs related to Life. d. Beliefs related to Relations-Beliefs related to functions. 2. Human experience: a. Subjective health b. Subjective I-strength. c. Self-assessed QOL. d. Quality of relations (including sexual satisfaction). e. Self-assessed functions. 3. Human life manifestations: a. Objective physical health. b. objective mental health. c. Objective relations. d. Objective functions. The presented model for the development of AIDS and the subsequent process of healing AIDS by rebalancing and sharpening the immune systems response, comes from a combination of the State-of-Life Theory with the classical psychosomatic theory and healing practice. This method for healing a weak immune system was first described by "the father of western medicine", the priest-healer Hippocrates, and his students around 400 BCE. [ABSTRACT FROM AUTHOR]

Citrus wilt is a disease of recent appearance in the northern area of Veracruz that causes economic losses to producers in the region. The present work aimed to identify the causative agent of this disease and evaluate different fungicides to determine its in vitro sensitivity. A fungus was consistently isolated in plants with wilt symptoms; it was morphologically identified in different culture media and molecularly identified by PCR using the EF1-728F/EF1-986R primers. The fungus was inoculated in three varieties of citrus under greenhouse conditions. The sensitivity test was carried out with the fungicides chlorothalonil, benomyl thiabendazole, prochloraz, and a biological agent (Bacillus subtilis) at different concentrations, plus a negative control. Fusarium sp. (Accession No. MW438335) was morphologically and molecularly identified as the causal agent of vascular wilt in citrus fruits, causing growth retardation, decreased number of roots, wilting of the apical bud, and necrosis in the vascular system of the three varieties inoculated. The most effective fungicides in inhibiting mycelial growth were thiabendazole, prochloraz, and the biological agent Bacillus subtilis. [ABSTRACT FROM AUTHOR]

Tsukamurella , a group of multi-drug resistant, Gram-positive, aerobic, and partially acid-fast bacteria, are emerging causes of bacterial conjunctivitis and keratitis. However, the pathogenesis of Tsukamurella keratitis is largely unknown. To address this, we used New Zealand White rabbits to develop the first eye infection model and conducted in vitro tests to study the pathogenesis mechanisms of Tsukamurella . There is increasing evidence that biofilms play a significant role in ocular infections, leading us to hypothesize that biofilm formation is crucial for effective Tsukamurella infection. In order to look for potential candidate genes which are important in biofilm formation and Tsukamurella keratitis. We performed genome sequencing of two ocular isolates, T. pulmonis -PW1004 and T. tyrosinosolvens -PW899, to identify potential virulence factors. Through in vitro and in vivo studies, we characterized their biological roles in mediating Tsukamurella keratitis. Our findings confirmed that Tsukamurella is an ocular pathogen by fulfilling Koch's postulates, and using genome sequence data, we identified tmytC, encoding a mycolyltransferase, as a crucial gene in biofilm formation and causing Tsukamurella keratitis in the rabbit model. This is the first report demonstrating the novel role of mycolyltransferase in causing ocular infections. Overall, our findings contribute to a better understanding of Tsukamurella pathogenesis and provide a potential target for treatment. Specific inhibitors targeting TmytC could serve as an effective treatment option for Tsukamurella infections.

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Abstract Purpose Aphis gossypii and A. punicae are the most damaging pests. The emergence of large populations has created concern among farmers because this pest complex is considered critical as it has a significant effect on major crops around the globe. The lack of new technologies for the control of A. gossypii and A. punicae is also worrying due to the indiscriminate use of chemical insecticides. Besides, this leads to the rapid development of resistance, which strangles their control in the field. Hence, there is a dire need to find the effective biocontrol agent for the management of Aphis gossypii and A. punicae. Methods The present investigation emphasizes the isolation and characterization of Aphidicidal Bacillus thuringiensis from the Andaman and Nicobar Islands, Karnataka, Assam, Arunachal Pradesh, and Sikkim soil samples. Phase contrast and scanning electron microscopy analysis used to characterize and identify the crystal morphology. Molecular profiling of Bt cry genes was determined by PCR using aphidicidal cry gene-specific primers, and molecular cloning and sequencing were carried out. Protein profiling by SDS–PAGE analysis was further studied. Finally, a qualitative bioassay of insecticidal activity was carried out against A. gossypii and A. punicae. Results A total of 65 Bacillus-like colonies were screened; 15 putative Aphidicidal B. thuringiensis isolates were identified based on morphological as well as through microbiological studies. Spherical and amorphous crystal inclusion was predominantly present in 34.28% of the Bt isolates. Crystal protein profiling of Bt isolates by SDS–PAGE analysis showed the presence 130, 73, 34, 25, and 13 kDa bands, among which 50−66 kDa bands were present abundantly. The detection of the cry gene of these isolates was done by PCR analysis, which indicated that cry1, cry2A, cry3A, and cry11A were on plasmid DNA. All cry genes were 80–100% homologous when aligned on alignment tool NCBI-BLASTn and BLASTp. All isolates of Bt were tested for their insecticidal activity against aphids. Three of the 15 isolates are Aphidicidal toxin specific by PCR analysis which were observed to be toxic to Aphis gossypii and A. punicae at a concentration of 35 μg/mL. The observed physical changes were induced by B. thuringiensis infection; these strains had been re-isolated from the dead aphids, and the presented results fulfilled Koch’s postulates. Conclusion The present study brought promising Bt isolates, primarily capable of creating an efficient biocontrol agent for Aphis gossypii and A. punicae and various sucking pests soon.

Verticillium spp., including V. nonalfalfae and V. dahliae, are known vascular wilt pathogens of the invasive Ailanthus altissima (tree-of-heaven) in the United States and in Europe. Herein we provide evidence of the presence of a previously unreported wilt disease of A. altissima in Tuscany (Central Italy). Several isolates were collected from two locations and identified as V. dahliae, based on microscopical features of conidiophores, conidia and microsclerotia. Genomic DNA was extracted from the mycelium, the ITS region was amplified and the sequence was deposited in GenBank as VdGL16 (accession no. MK474459). BLASTn analysis showed 100% similarity with V. dahliae. To confirm pathogenicity of VdGL16, inoculations of Ailanthus seedlings were performed with the root dipping technique whereas mature trees were stem-inoculated. All inoculated seedlings exhibited wilt symptoms after 20 days, while mature Ailanthus trees showed wilting and dieback after six months. The pathogen was easily re-isolated from seedlings and re-identified as V. dahliae, thus satisfying Koch’s postulates. Results from intraspecific resistance screening of nine seed sources from across Italy revealed that Ailanthus provenances from all the six sampled regions were susceptible to V. dahliae. Stem inoculated adult plants exhibited abundant production of epicormic sprouts along the stem within six months, and most of these sprouts wilted following initial dieback of the main stem; furthermore, sprouting from the crown was intense. Petioles and rachises tissues of leaves fallen from infected trees were a good source for re-isolation of the pathogen; we proved that such petioles and rachises can effectively transfer the fungus to healthy Ailanthus seedlings via root infections. Host-specificity of the V. dahliae isolate VdGL16 was also determined on 40 non-target species/varieties/cultivars. The isolate caused disease in herbaceous species belonging to five botanical families: Asteraceae, Lamiaceae, Leguminoseae, Linaceae and Solanaceae. Given the difficulties in countering Ailanthus invasion with mechanical and chemical methods, the biological control using Verticillium may provide an efficient, low cost and sustainable control of this invasive species.

Anthracnose is one of the major problems for cultivating many crops, including vegetables, fruits, and trees. It is a continual threat for fruits grower worldwide. Colletotrichum fructicola was isolated from Shine Muscat berries showing typical anthracnose symptom in Korea. It was identified as C. fructicola based on morphology, pathological signs and concatenated sequences of internal transcribed spacer region of rDNA, glyceraldehyde-3-phosphate dehydrogenase, β-tubulin-2, chitin synthase-1, calmodulin, and the Apn2-Mat1-2 intergenic spacer and partial mating type (Mat1-2) gene. To the best of our knowledge, this is the first report first report of anthracnose of Shine Muscat caused by C. fructicola in Korea.

Ramularia mali Videira & Crous is an emerging postharvest pathogen on apple (Malus × domestica Borkh.) in Italy and other apple producing countries (Prencipe et al. 2023). After 3 to 6 months of cold storage at 1 - 2 °C and low oxygen levels of 0.5 - 2 %, lenticels show black-brown speckled dry rot of 1 mm - 5 mm in diameter, without colonizing underlying tissue. The most affected cultivar (cv.) in South Tyrol (northern Italy) is Golden Delicious and postharvest losses due to characteristic lenticel spots range from 10 % to above 50 %. Four symptomatic fruits, originating from two orchards (Latsch/Laces and Bozen/Bolzano; South Tyrol, Italy), respectively, were sampled after cold storage (= ultra-low oxygen; 0.5 % O2 and 1 °C). After surface disinfection with 70 % EtOH for 1 min, sixteen explants from lenticel spots were cultivated on potato dextrose agar (PDA) at 25 °C. Two isolates, morphologically identified as Ramularia sp., were sequenced and showed high identities to R. mali type culture CBS 129581: 100 % and 99.31 % identity for ITS region (MH865432); 94.66 % and 91.41 % for TEF-1α (KJ504693); 97.22% and 97.40% for RpbII (KJ504649). Isolates were cultivated at 25 °C for 2 weeks and conidia were harvested with 3.0 mL 0.05 % Tween®20. Inoculation was performed in triplicate on 5-month cold stored fruits cv. Golden Delicious. After surface disinfection for 1 min with cotton swabs, which were immersed in 70 % EtOH, 10 µL spore suspension of each isolate (8.50 × 107 spores mL-1 in 0.05 % Tween®20) were injected horizontally beneath the epidermis with a syringe (Hamilton® model 710N). Also, a mixture of both isolates was used. Controls were carried out with 0.05 % Tween®20 only. Apples were stored either at 9 °C in the dark or at 1°C and 0.5 % oxygen for 4 months. First symptoms were observed for both spore concentrations after 2 weeks at 9 °C. The injection pathway changed to a brownish color, whereas the control did not show any change (Fig. 1). Final evaluation was carried out after 4 months, but the fruits did not show further symptom development. Fruits stored at 1°C for 5 months were simultaneously evaluated, confirming that the pathogen invaded the tissue surrounding the injection site, without penetrating deeper into the fruit flesh. (Fig. 2). Reisolation from artificially infected apples was successfully achieved, and sequence analysis was performed on the DNA extracts from the obtained isolates. Concatenated sequences of ITS (deposited to GenBank under the accession numbers: PP439643 -PP439647), TEF-1α (PP480231-PP480235), and RbpII (PP480226-PP480230) were subjected to multi-locus sequence analysis. References sequences of R. nyssicola CBS 127665, R. collo-cygni CBS 101181, R. vizellae CBS 115981, R. eucalypti CBS 120726, R. hydrangeae-macrophyllae CBS 122272, R. glennii CBS 129441 and R. mali CBS 129581 included and aligned by the CLUSTALW algorithm within the software Geneious® 11.1.5 (Biomatters Inc., New Zealand). Phylogeny was reconstructed with MEGAX (Version 10.2.6) (Kumar et al. 2018) based on the Maximum Likelihood (ML) algorithm (Fig. 3). Isolates from artificially infected fruit clustered with the R. mali type culture. Although Gianetti et al. (2012) and Lindner (2013), respectively, first described Ramularia sp. as a postharvest pathogen on apple, the present study demonstrated the reproduction of lenticel dry rot symptoms by R. mali.

“Hongtuozhusun” (Phallus rubrovolvatus) is an important edible and medicinal mushroom endemic to Southwest China. However, yellow rot disease is a severe disease of P. rubrovolvatus that occurs extensively in Guizhou Province. It has caused major economic losses and hinders the development of the P. rubrovolvatus industry. In this study, 28 microorganism strains were isolated from diseased fruiting bodies of P. rubrovolvatus at various stages, two of which were confirmed to be pathogenic based on Koch’s postulates. These two strains are introduced herein as Saccharomycopsis phalluae sp. nov. based on morphological, physiological, and molecular analysis. We reported a high-quality de novo sequencing and assembly of the S. phalluae genome using singlemolecule real-time sequencing technology. The whole genome was approximately 14.148 Mb with a G+C content of 43.55%. Genome assembly generated 8 contigs with an N50 length of 1,822,654 bp. The genome comprised 5966 annotated protein-coding genes. This is the first report of mushroom disease caused by Saccharomycopsis species. We expect that the information on genome properties, particularly in pathogenicity-related genes, assist in developing effective control measures in order to prevent severe losses and make amendments in management strategies. [ABSTRACT FROM AUTHOR]

Ceratobasidium lantanae-camarae was a name proposed for a fungus associated with white thread blight disease of Lantana camara (common lantana): a Brazilian native plant listed amongst the world's ten worst weeds. This fungus was found during surveys in Brazil to assess the potential of coevolved fungal pathogens as classical biocontrol agents in the Paleotropics and Australasia. Later, in a monograph on Rhizoctonia forming-fungi, C. lantanae-camarae was synonymized with C. cornigerum: a polyphagous species recorded worldwide, but never previously from Latin America. The lack of pure cultures of C. lantanae-camarae did not allow a verification of the true status of the white thread blight fungus on lantana. Recently, the lantana disease was observed in localities in the Brazilian states of Rio de Janeiro and Amazonas. Pure cultures were obtained, DNA was extracted and phylogenetic analyses of the ITS-5.8S rDNA region were performed. Results showed that C. lantanae-camarae and C. cornigerum are phylogenetically distinct and that their synonymization was a taxonomic error. It was also found that, although C. lantanae-camarae is phylogenetically close to C. papillatum, morphological differences between these two species are evident. Thus, the name C. lantanae-camarae is re-established herein: an epitype and a reference ex-epitype sequence are indicated, resolving this taxonomic issue. Additionally, Koch's postulates were fulfilled for the first time. The significance of this taxonomic elucidation for weed biocontrol is discussed. [ABSTRACT FROM AUTHOR]