Revisiting Alternaria-host interactions: New insights on its pathogenesis, defense mechanisms and control strategies

Ali, Sajad; Tyagi, Anshika; Rajarammohan, Sivasubramanian; Mir, Zahoor A; Bae, Hanhong

doi:10.1016/j.scienta.2023.112424

Cited by 15 publications

(14 citation statements)

References 168 publications

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“…Alternaria spp. release host-specific toxins to aid its pathogenicity [34]. These toxins target the host cell and its organelles, including the Golgi complex, mitochondria, plasma membrane, nucleus, and metabolic pathways such as ceramide and ATP synthesis [34].…”

Section: Discussionmentioning

confidence: 99%

“…release host-specific toxins to aid its pathogenicity [34]. These toxins target the host cell and its organelles, including the Golgi complex, mitochondria, plasma membrane, nucleus, and metabolic pathways such as ceramide and ATP synthesis [34]. Most of the existing studies on the pathogenicity of apple leaf spot have focused on toxins, and several toxins, such as AM-toxin-1 and AM-toxin-4, have been isolated [35].…”

Section: Discussionmentioning

confidence: 99%

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Pathogenic Factors and Mechanisms of the Alternaria Leaf Spot Pathogen in Apple

Cao,

Gong,

et al. 2024

Horticulturae

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Alternaria leaf spot seriously threatens the sustainable development of the global apple industry, causing significant losses and reducing fruit quality and yield. The causal agent Alternaria alternata f. sp. mali (Alternaria mali, ALT) produces various molecules to modulate infection, such as cell wall-degrading enzymes, toxins, and elicitor-like molecules. ALT produces the host-specific AM-toxin, an important pathogenicity factor. ALT also releases effectors into apple cells that modify host defense, but these proteins have not yet been described. Here, we identified the pathogenic fungal types responsible for early defoliation from diseased leaves of Fuji (Malus domestica cv. ‘Fuji’) apple collected from five districts in Shandong Province, China. The ALT isolates ALT2 to ALT7 were pathogenic to four apple cultivars, with ALT7 being the most aggressive. We extracted mycotoxins (AM-toxin-2 to AM-toxin-7) from each isolate and used them to treat different apple varieties, which led to leaf-spot symptoms and damaged chloroplasts and nuclear membranes, followed by cell death. AM-toxin-7 produced the most severe symptoms, but chloroplasts remained intact when the mycotoxin was inactivated. Mass spectrometry identified 134 secretory proteins in ALT7 exosomes, and three secreted proteins (AltABC, AltAO, and AltPDE) were confirmed to be involved in apple pathogenesis. Therefore, ALT secretes AM-toxin and secretory proteins as an infection strategy to promote fungal invasion and overcome the host defense system.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Pathogenic Factors and Mechanisms of the Alternaria Leaf Spot Pathogen in Apple

Cao,

Gong,

et al. 2024

Horticulturae

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“…Alternaria is a common genus that occurs frequently as a saprotroph of decaying organic matter, but few species are plant pathogens. Diseases caused by Alternaria species are widespread, and can affect other crops such as tomatoes, apples, carrots, and potatoes [50,51]. The economic impact on agricultural production is significant, as it affects the plant at all stages of development, from seed germination to post-harvest [21,49,52].…”

Section: Black Spot Disease In Brassicaceaementioning

confidence: 99%

“…The infection process begins with fungal penetration into the plant through wounds or stomata [20]. Once inside the plant, the fungus secretes secondary metabolites, toxins [53,54], and a series of hydrolytic enzymes such as proteases, lipases, and Cell Wall-Degrading Enzymes (CWDEs) leading to the death of plant tissues and facilitating the entry of the fungus into plant cells [48,50,55]. In leaf tissue, disease symptoms include leaf spots, yellow chlorotic halos, necrotic lesions, and leaf size reduction, resulting in a decrease of leaf photosynthetic capacity.…”

Section: Black Spot Disease In Brassicaceaementioning

confidence: 99%

“…In leaf tissue, disease symptoms include leaf spots, yellow chlorotic halos, necrotic lesions, and leaf size reduction, resulting in a decrease of leaf photosynthetic capacity. In seedlings, a symptom known as damping off occurs, and is characterized by the rotting of the plants stem base and roots, wilting, and causing the death of young plants as a consequence of the infection [48,50,55].…”

Section: Black Spot Disease In Brassicaceaementioning

confidence: 99%

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First Report on the Seed Immune Response to Fungal Necrotrophs Attack

Ortega-Cuadros,

Aligon,

Arias

et al. 2024

Preprint

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Seeds play a vital role in the perpetuation of plant species, both in natural environments and agriculture. However, they often face challenges from biotic stresses, such as seedborne pathogenic fungi. The transgenerational transmission of these seedborne fungi, along with their dissemination during seed commercialization, can contribute to the emergence of global epidemic diseases, resulting in substantial economic losses. One such pathogenic fungus is Alternaria brassicicola, responsible for causing black spot disease in Brassicaceae. This necrotrophic seedborne fungus negatively impacts plant development, consequently affecting crop production and seed quality. To gain a deeper understanding of the interaction between seeds and necrotrophic fungi, the Arabidopsis thaliana/Alternaria brassicicola model pathosystem has been extensively studied. Recent transcriptomic and genetic studies revealed a distinctive immune response of seeds against this pathogen, divergent from the immune response described in the plant vegetative phase. In germinating seeds and seedlings, the necrotrophic fungus seems to induce susceptible response [1]. It was observed at the RNA level that to the detriment of jasmonic acid pathway, Alternaria induced the salicylic acid and glucosinolate (GSL) pathways. Genetic evidence identified that seedling necrosis, potentially beneficial to the growth of the necrotrophic agent, is hypersensitive response mediated by GSL pathway. Transmission of necrotrophic fungal from seed to seedling unveils novel regulations of the immune response, that would illustrate a trade-off between seedling establishment and fungal infection. This knowledge is promising to sustainably ensure the sanitary quality of crops.

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Thermal image evaluation of crop diseases in the incubation period

Yang,

Zhang,

Zhou

et al. 2024

J Sci Food Agric

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BACKGROUNDEarly blight is one of the main diseases that causes serious pepper yield and quality reduction. The identification of the presymptomatic features during the incubation period is of great research significance, in that scientific prevention measures in the incubation period may effectively reduce the loss of peppers.RESULTSThe present study confirms the feasibility of the identification of presymptomatic features in pepper early blight by infrared thermography during the incubation period. The infrared thermal images of pepper blades were captured during the whole incubation period in our experiment. Evaluation parameters such as temperature uniformity (U) and the variation coefficient (C) were established by infrared thermal images for the blade temperature field. Evaluation parameters such as temperature uniformity U and variation coefficient C of pepper blades change during the time from being inoculated to significant morbidity. For cases of stabbing inoculation, there were no relatively obvious symptoms in visible light images until 96 h after inoculation, whereas some presymptomatic features appeared in infrared thermal images at 60 h after inoculation. Based on the uniformity changes (δU) and the variation coefficient changes (δC) in the temperature field distribution, the characteristic polynomial (CP)‐GBDT model has been established by optimizing the gradient boosting decision tree (GBDT) model. Compared with the GBDT mode, the CP‐GBDT model accuracy increased from 87.5% to 91.7% on the test set.CONCLUSIONEvaluation parameters such as temperature uniformity U and variation coefficient C can be used to effectively characterize the presymptomatic features of pepper early blight by infrared thermography during the incubation period. The results of the present study can provide a reference for the detection of crop diseases in the incubation period. © 2024 Society of Chemical Industry.

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Revisiting Alternaria-host interactions: New insights on its pathogenesis, defense mechanisms and control strategies

Cited by 15 publications

References 168 publications

Pathogenic Factors and Mechanisms of the Alternaria Leaf Spot Pathogen in Apple

Pathogenic Factors and Mechanisms of the Alternaria Leaf Spot Pathogen in Apple

First Report on the Seed Immune Response to Fungal Necrotrophs Attack

Thermal image evaluation of crop diseases in the incubation period

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