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Plant Disease Jun 2024The Chinese quince (Chaenomeles sinensis (Thouin) Koehne), belongs to the Rosaceae family, is widely distributed throughout Asia, including Republic of Korea. It is used...
The Chinese quince (Chaenomeles sinensis (Thouin) Koehne), belongs to the Rosaceae family, is widely distributed throughout Asia, including Republic of Korea. It is used as a traditional treatment for asthma, common cold, and dry pharynx. Numerous recent pharmacological studies on antiinfluenza, antioxidant, and antidiabetic properties have confirmed the medicinal properties of the Chinese quince fruit (Chun et al., 2012). In March 2022, leaf spots on Chinese quince, resulting in defoliation, were observed in Andong, Gyeongsangbuk Province, Korea (Fig. 1A). The disease symptoms are dark brown spots on leaves. Later, the chlorophyll is lost, causing the entire leaf to become wilted and fell off (Fig. 1B). To identify the pathogen, symptomatic leaves were brought to the laboratory, cut into small pieces, and surface-disinfected in 70% ethanol for 15 s and rinsed with sterile distilled water (SDW). The specimens were then treated with 1% NaOCl for 15 s, followed by rinsing with SDW. Thus, surface-disinfected tissues were placed onto potato dextrose agar (PDA) plates and incubated at 25°C for 7 d. A total of four isolates were obtained from the infected leaves. The colonies were transferred onto freshly prepared PDA plates by the single spore method for further purification. GYUN-10746 isolate was selected as the representative strain among the four isolates and deposited in the Korean Agricultural Culture Collection (KACC 410367). They initially produced white mycelia, which turned dark brown or pale brown at the center and beige at the periphery after 7 d (Fig. 1C and D). Conidiophores were pyriform, sometimes ovoid, or ellipsoidal and brown, measuring 30.8 ± 0.49 × 12.9 ± 0.26 µm (length × width) (n=100) (Fig. 1E). The morphological characteristics were consistent with those of Alternaria alternata (Woudenberg et al. 2015). For molecular identification, DNA was amplified using the following primers: ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone et al. 1999), Gpd-R/Gpd-F (Berbee et al. 1999), Alt a1-F/Alt a1-R (Hong et al. 2005) and rpb2F/rpb2R (Liu et al. 1999) by PCR. DNA sequences from all 4 isolates (GYUN-10746, GYUN-11193, GYUN-11194 and GYUN-11195) were identical. The ITS (OP594615), TEF1-α (OR327062), GAPDH (OR372157), Alt a 1 (OR327061), and RPB2 (OR352741) sequences from the representative isolate GYUN-10746 were 100% identical to those of previously identified A. alternate isolates. A phylogenetic tree was constructed using sequences of ITS, TEF1-α, GAPDH, Alt a l, and RPB2 to illustrate their relationship with A. alternata and related Alternaria species (Fig. 2). For the pathogenicity test, healthy Chinese quince branch containing leaves were inoculated with 7-day-old mycelial plugs of A. alternata, while leaves on a branch inoculated with PDA plugs alone served as a control group. Thus inoculated branches were incubated at 25°C for 7 d. Disease symptoms were developed on leaves of the branches inoculated with mycelial plugs of the fungal pathogen (Fig. 1F), while no symptoms developed on control group. The resulting leaf spots resembled those on the original infected plants. To confirm Koch's postulates, the pathogen was re-isolated from inoculated leaves with identical morphological and molecular characteristics. To the best of our knowledge, this is the first report of leaf spot caused by A. alternata in C. sinensis in Korea. The identification of the pathogen may provide pertinent information for the development of disease controlling strategies.
PubMed: 38916907
DOI: 10.1094/PDIS-05-24-0984-PDN -
BioRxiv : the Preprint Server For... Jun 2024Vagal sensory neurons convey sensations from internal organs along the vagus nerve to the brainstem. Pruriceptors are a subtype of neurons that transmit itch and induce...
Vagal sensory neurons convey sensations from internal organs along the vagus nerve to the brainstem. Pruriceptors are a subtype of neurons that transmit itch and induce pruritus. Despite extensive research on the molecular mechanisms of itch, studies focusing on pruriceptors in the vagal ganglia still need to be explored. In this study, we characterized vagal pruriceptor neurons by their responsiveness to pruritogens such as lysophosphatidic acid, -alanine, chloroquine, and the cytokine oncostatin M. We discovered that lung-resident basophils produce oncostatin M and that its release can be induced by engagement of Fc RI . Oncostatin M then sensitizes multiple populations of vagal sensory neurons, including Tac1 and MrgprA3 neurons in the jugular ganglia. Finally, we observed an increase in oncostatin M release in mice sensitized to the house dust mite or to the fungal allergen , highlighting a novel mechanism through which basophils and vagal sensory neurons may communicate during type I hypersensitivity diseases such as allergic asthma.
PubMed: 38915548
DOI: 10.1101/2024.06.11.598517 -
Microbiology Spectrum Jun 2024Previous work identified a pair of specific effectors AsCEP19 and AsCEP20 in as contributors to the virulence of . Here, we constructed and deletion mutants in...
UNLABELLED
Previous work identified a pair of specific effectors AsCEP19 and AsCEP20 in as contributors to the virulence of . Here, we constructed and deletion mutants in strain HWC168 to further reveal the effects of these genes on the biology and pathogenicity of . Deletion of and did not affect vegetative growth but did affect conidial maturation, with an increase in the percentage of abnormal conidia produced. Furthermore, we determined the expression patterns of genes involved in the conidiogenesis pathway and found that the regulatory gene was significantly upregulated and , a positive regulator for conidiation, was significantly downregulated in the mutant strains compared to the wild-type strain. These results suggest that AsCEP19 and AsCEP20 indirectly affect the conidial development and maturation of . Pathogenicity assays revealed significantly impaired virulence of Δ, Δ and Δ mutants on potato and tomato plants. Moreover, we performed localization assays with green fluorescent protein-tagged proteins in chili pepper leaves. We found that AsCEP19 can specifically localize to the chloroplasts of chili pepper epidermal cells, while AsCEP20 can localize to both chloroplasts and the plasma membrane. Weighted gene co-expression network analysis revealed enrichment of genes of this module in the photosynthesis pathway, with many hub genes associated with chloroplast structure and photosynthesis. These results suggest that chloroplasts are the targets for AsCEP19 and AsCEP20.
IMPORTANCE
is an important necrotrophic pathogen causing potato early blight. Previous studies have provide preliminary evidence that specific effectors AsCEP19 and AsCEP20 contribute to virulence, but their respective functions, localization, and pathogenic mechanisms during the infection process of remain unclear. Here, we have systematically studied the specific effectors AsCEP19 and AsCEP20 for the first time, which are essential for conidial maturation. The deletion of AsCEP19 and AsCEP20 can significantly impair fungal pathogenicity. Additionally, we preliminarily revealed that AsCEP19 and AsCEP20 target the chloroplasts of host cells. Our findings further enhance our understanding of the molecular mechanisms underlying the virulence of necrotrophic pathogens.
PubMed: 38912810
DOI: 10.1128/spectrum.04214-23 -
Frontiers in Plant Science 2024[This corrects the article DOI: 10.3389/fpls.2023.1278127.].
[This corrects the article DOI: 10.3389/fpls.2023.1278127.].
PubMed: 38911985
DOI: 10.3389/fpls.2024.1435731 -
Scientific Reports Jun 2024Intensification of staple crops through conventional agricultural practices with chemical synthetic inputs has yielded positive outcomes in food security but with...
Intensification of staple crops through conventional agricultural practices with chemical synthetic inputs has yielded positive outcomes in food security but with negative environmental impacts. Ecological intensification using cropping systems such as maize edible-legume intercropping (MLI) systems has the potential to enhance soil health, agrobiodiversity and significantly influence crop productivity. However, mechanisms underlying enhancement of biological soil health have not been well studied. This study investigated the shifts in rhizospheric soil and maize-root microbiomes and associated soil physico-chemical parameters in MLI systems of smallholder farms in comparison to maize-monoculture cropping systems (MMC). Maize-root and rhizospheric soil samples were collected from twenty-five farms each conditioned by MLI and MMC systems in eastern Kenya. Soil characteristics were assessed using Black oxidation and Walkley methods. High-throughput amplicon sequencing was employed to analyze fungal and bacterial communities, predicting their functional roles and diversity. The different MLI systems significantly impacted soil and maize-root microbial communities, resulting in distinct microbe sets. Specific fungal and bacterial genera and species were mainly influenced and enriched in the MLI systems (e.g., Bionectria solani, Sarocladium zeae, Fusarium algeriense, and Acremonium persicinum for fungi, and Bradyrhizobium elkanii, Enterobacter roggenkampii, Pantoea dispersa and Mitsuaria chitosanitabida for bacteria), which contribute to nutrient solubilization, decomposition, carbon utilization, plant protection, bio-insecticides/fertilizer production, and nitrogen fixation. Conversely, the MMC systems enriched phytopathogenic microbial species like Sphingomonas leidyi and Alternaria argroxiphii. Each MLI system exhibited a unique composition of fungal and bacterial communities that shape belowground biodiversity, notably affecting soil attributes, plant well-being, disease control, and agroecological services. Indeed, soil physico-chemical properties, including pH, nitrogen, organic carbon, phosphorus, and potassium were enriched in MLI compared to MMC cropping systems. Thus, diversification of agroecosystems with MLI systems enhances soil properties and shifts rhizosphere and maize-root microbiome in favor of ecologically important microbial communities.
Topics: Zea mays; Soil Microbiology; Soil; Agriculture; Rhizosphere; Microbiota; Crops, Agricultural; Ecosystem; Plant Roots; Biodiversity; Bacteria; Fungi; Kenya; Crop Production
PubMed: 38906908
DOI: 10.1038/s41598-024-64138-w -
ELife Jun 2024Microbes strongly affect invasive plant growth. However, how phyllosphere and rhizosphere soil microbes distinctively affect seedling mortality and growth of invaders...
Microbes strongly affect invasive plant growth. However, how phyllosphere and rhizosphere soil microbes distinctively affect seedling mortality and growth of invaders across ontogeny under varying soil nutrient levels remains unclear. In this study, we used the invader to evaluate these effects. We found that higher proportions of potential pathogens were detected in core microbial taxa in leaf litter than rhizosphere soil and thus leaf inoculation had more adverse effects on seed germination and seedling survival than soil inoculation. Microbial inoculation at different growth stages altered the microbial community and functions of seedlings, and earlier inoculation had a more adverse effect on seedling survival and growth. The soil nutrient level did not affect microbe-mediated seedling growth and the relative abundance of the microbial community and functions involved in seedling growth. The effects of some microbial genera on seedling survival are distinct from those on growth. Moreover, the seedling-killing effects of fungal strains isolated from dead seedlings by non-sterile leaf inoculation exhibited significant phylogenetic signals, by which strains of and generally caused high seedling mortality. Our study stresses the essential role of litter microbes in population establishment by regulating seedling density and growth.
Topics: Ageratina; Rhizosphere; Seedlings; Plant Leaves; Soil Microbiology; Microbiota; Introduced Species; Germination
PubMed: 38896455
DOI: 10.7554/eLife.95502 -
Combination of with difenoconazole to control pear black spot and the related synergistic mechanism.Frontiers in Microbiology 2024Pear black spot (PBS) is caused by and causes severe damage worldwide. It is particularly important to screen for synergistic fungicide combinations to address issues...
BACKGROUND
Pear black spot (PBS) is caused by and causes severe damage worldwide. It is particularly important to screen for synergistic fungicide combinations to address issues associated with the low efficacy of biocontrol agents, high dosage requirements and poor sustained effectiveness of chemical fungicides.
METHODS
and studies were performed to determine the efficacy of a treatment for this important disease. Additionally, transcriptomic and metabolomic analyses were performed to determine the main molecular and biochemical mechanisms involved in the interaction.
RESULTS
2_2a has a significant synergistic effect with difenoconazole, causing hyphal entanglement and spore lysis and inhibiting the formation of PBS lesions . In the field, the control effect of the combination was greater than 95%. The pathways associated with the synergistic effect on the mycelia of were divided into two main types: one included glycolysis, oxidative phosphorylation, and MAPK signal transduction, while the other included glycolysis, the TCA cycle, coenzyme A biosynthesis, sterol synthesis, and fatty acid degradation. Both types of pathways jointly affect the cell cycle. The main functions of the key genes and metabolites that have been verified as being affected are glucose synthesis and oxidative respiration, as well as citric acid synthesis, acetyl-CoA synthesis, and sterol synthesis. Both functions involve intracellular pyridine nucleotide metabolism and adenine nucleotide transformation.
CONCLUSION
This study helps to reveal the synergistic mechanisms underlying the combined efficacy of biological and chemical agents, providing a scientific basis for field applications.
PubMed: 38894972
DOI: 10.3389/fmicb.2024.1405039 -
Molecules (Basel, Switzerland) May 2024Plant pathogenic fungi pose a major threat to global food security, ecosystem services, and human livelihoods. Effective and broad-spectrum fungicides are needed to...
Plant pathogenic fungi pose a major threat to global food security, ecosystem services, and human livelihoods. Effective and broad-spectrum fungicides are needed to combat these pathogens. In this study, a novel antifungal 2-oxyacetate hydrazide quinoxaline scaffold as a simple analogue was designed and synthesized. Their antifungal activities were evaluated against (), (), (), (), (), and (). These results demonstrated that most compounds exhibited remarkable inhibitory activities and possessed better efficacy than ridylbacterin, such as compound (EC = 0.87 μg/mL against , EC = 1.01 μg/mL against ) and compound (EC = 1.54 μg/mL against , EC = 0.20 μg/mL against ). The 3D-QSAR analysis of quinoxaline-2-oxyacetate hydrazide derivatives has provided new insights into the design and optimization of novel antifungal drug molecules based on quinoxaline.
Topics: Quantitative Structure-Activity Relationship; Antifungal Agents; Quinoxalines; Microbial Sensitivity Tests; Drug Design; Alternaria; Rhizoctonia; Botrytis; Molecular Structure; Colletotrichum; Gibberella
PubMed: 38893377
DOI: 10.3390/molecules29112501 -
Polymers May 2024The impact of methyl salicylate (MeSA) or sodium nitroprusside (SNP) in chitosan (CS)/Gum Arabic (GA) mixture on physio-chemical characteristics and antioxidant status...
The impact of methyl salicylate (MeSA) or sodium nitroprusside (SNP) in chitosan (CS)/Gum Arabic (GA) mixture on physio-chemical characteristics and antioxidant status during the postharvest ripening of green tomato fruits was studied. CS/GA-MeSA at a 1 mM formulation was the best treatment to retard firmness and titratable acidity (TA) losses. Moreover, this formulation retarded pigmentation progress where it had the lowest significant values of total carotenes (TCs) and lycopene (LYP) contents until the 15th day of the storage period, as well as efficiently faced the rise in malondialdehyde (MDA) levels. Moreover, peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and phenylalanine ammonia-lyase (PAL) activities of tomatoes treated with CS/GA-SNP at 2 mM were significantly better than that of control in the primary stages of storage. CS/GA-SNP at a 2 mM formulation showed an extremely high significant content of total polyphenol (TP) in the early stage of storage, while CS/GA and CS/GA-MeSA at 1 and 2 mM accumulated higher significant TP contents than uncoated fruits at the late stage of storage. All formulations were characterized by FTIR spectroscopy. Furthermore, the polymer formulations exhibited strong antifungal activity against and as major pathogens of postharvest tomatoes. Transmission electron microscope (TEM) observations for the mycelia of both fungi treated by CS/GA-MeSA at 2 mM revealed serious ultrastructural damage, including distortion of the cell wall and cell membrane and degradation of cytoplasmic organelles.
PubMed: 38891464
DOI: 10.3390/polym16111518 -
Plant Disease Jun 2024Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant. In April 2022, a leaf disease on D. stramonium was observed in...
Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant. In April 2022, a leaf disease on D. stramonium was observed in Zhanjiang (21.17 N, 110.18 E), Guangdong province, China. Early symptoms were small yellow spots on leaves. Later, the spots gradually expanded and turned becoming necrotic with a clear yellow halo and a white center. The disease incidence in the field was 85% (n = 50, about 1 ha). Twenty diseased leaves were collected from the field. The margin of the diseased tissues was cut into 2 mm × 2 mm pieces, surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively, and rinsed twice with sterile water before isolation. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. After 2-day incubation, grayish fungal colonies appeared on the PDA, then pure cultures were produced by transferring hyphal tips to new PDA plates. Single-spore isolation method was used to recover pure cultures for three isolates (DSAC-1, DSAC-2, and DSAC-3). The isolates were morphologically identical . They colonies were gray to brownish black. Conidiophores were branched, brown. Conidia were brown, long ellipsoid, had 4-12 transverse and 0-3 longitudinal septa; measured within 67.5-127.8 (average = 105.6) × 12.5-27.8 (average = 20.4) µm (n = 30). Apical beak was longer than conidia body. measured within 40.5-423.5 (average = 365.2) × 2.5-5.8 (average = 3.2) µm (n = 30). Based on morphological characteristics, the three isolates were identified as Alternaria crassa (Sacc.) Rands (Simmons 2007). Molecular identification was performed using the colony polymerase chain reaction method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) to amplify internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RNA polymerase second largest subunit (RPB2) and translation elongation factor (TEF1) with primers of ITS1/ITS4, GDF1/GDR1, RPB2-5F2/fRPB2-7cR, and EF-1α-F/EF-1α-R, respectively (Walther et al. 2013; Woudenberg et al. 2015; Nishikawa and Nakashima. 2020). Amplicons of the isolates were sequenced and submitted to GenBank (ITS, ON430524-ON430526; GAPDH, ON500656-ON500658; RPB2, ON500659-ON500661; TEF1, ON500662-ON500664). The sequences were 100% identical with those of Alternaria crassa strain CBS 116647 upon BLAST analysis. The sequences were also concatenated for phylogenetic analysis by maximum likelihood. The isolates clustered with A. crassa (CBS 116647, CBS 116648, CBS CBS-110.38, and CBS_103.18 ). Thus, the fungus associated with leaf yellow spot on D. stramonium was identified as A. crassa. Pathogenicity tests were conducted in a greenhouse at 24 ℃-30 ℃ with 80% relative humidity using 3 isolates. Individual plants were grown in pots (n = 5, 1 month old). The unwounded leaflets were inoculated using three isolates (DSAC-1, DSAC-2, and DSAC-3). The fungal mycelium on 5 mm-diameter PDA plugs were placed faced down to the leaves. Sterile PDA was used for mock inoculated comtrols.. The test was performed three times. Disease symptoms were observed on the leaves after 7 days, whereas the controls remained healthy. The pathogen was re-isolated from infected leaves and was morphologically identical to the original isolates, fulfilling Koch's postulates. A. crassa was reported causing leaf spot on D. stramonium in Algeria (Nabahat et al. 2020). To our knowledge, this report is the first report of A. crassa causing leaf yellow spot on D. stramonium in China. This pathogen possesses potential biocontrol properties on the invasive weed, while this study also provides an important reference for the control of the disease of the medicinal plant.
PubMed: 38885028
DOI: 10.1094/PDIS-08-23-1494-PDN