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What are the different types of fungal pathogens?
What are the different types of fungal pathogens?
3 - biotrophic, necrotrophic, hemibiotrophic; 6 - monomertrophs; 11 - phylogenetics.
Which methods are used to combat fungal pathogens at a global level?
Which methods are used to combat fungal pathogens at a global level?
How are plant diseases classified by phenotype?
How are plant diseases classified by phenotype?
By symptom, by host, and by color.
Obligate pathogens can be cultured outside of their host plants.
Obligate pathogens can be cultured outside of their host plants.
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What are the classifications of saprotroph, biotroph, and necrotroph?
What are the classifications of saprotroph, biotroph, and necrotroph?
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Define hemibiotrophy.
Define hemibiotrophy.
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Do biotrophic pathogens feed on dead cells?
Do biotrophic pathogens feed on dead cells?
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What are some factors of biotrophs?
What are some factors of biotrophs?
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What are some factors of hemibiotrophs?
What are some factors of hemibiotrophs?
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What are some factors of necrotrophs?
What are some factors of necrotrophs?
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What are effectors?
What are effectors?
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What did scientists start to do when the three classes of pathogens became unclear?
What did scientists start to do when the three classes of pathogens became unclear?
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Study Notes
Classification of Plant Pathogens
- Fungal pathogens are categorized into three main types: biotrophs, necrotrophs, and hemibiotrophs, with additional distinctions of 6 monocotrophs and 11 phylogenetic classifications.
- Global strategies to combat plant pathogens include biosecurity, agronomy, genetic methods, and chemical treatments, with optimization in genetic and chemical approaches emphasized.
Phenotypic Classification of Plant Diseases
- Symptoms can classify plant diseases:
- Pathogen-related symptoms (rust, mildew, smut)
- Host symptoms (blotch, spot, dieback)
- Host-specific classifications include wheat and barley rust.
- Color-based classification includes yellow rust and brown rust.
Classification by Culturability
- Pathogens can be categorized based on culturing:
- Obligate pathogens require living plants to grow, while facultative pathogens can grow on dead organic matter.
- Culturability may not reflect feeding methods in the plant host.
Trophic Classifications
- Saprotrophs feed on dead organic matter; biotrophs consume living plant cells, while necrotrophs feed on dying or dead cells.
- Biotrophs cause symptoms reflective of the pathogen, whereas necrotrophs produce symptoms related to the host's response.
Hemibiotrophy Definition
- Hemibiotrophy exhibits both biotrophic and necrotrophic phases, identified by temporal and spatial differentiation in pathogenic interactions, notably in species like Colletotrichum and Magnaporthe grisea.
Evaluation of Trophic Trisomy
- Biotrophy classification tends to capture many pathogens but leaves questions for intermediaries.
- Noted pathogens include Cladosporium fulvum and Phytophthora infestans, displaying specific feeding mechanisms like haustoria for nutrient extraction.
Limitations of Trophic Trisomy
- Viruses are classified separately due to their intracellular nature, while bacteria are known for wilting and vascular blockage.
Factors Influencing Biotrophs
- Require living host cells and are obligate in nature, with haustoria for nutrient uptake.
- Typically exhibit a narrow host range and utilize salicylic acid in defense mechanisms.
- Engage in gene-for-gene interactions involving virulent effectors.
Characteristics of Hemibiotrophs
- Start off feeding on living cells, transitioning to dead tissue, and are facultative.
- Possess haustorium-like structures; narrow host range; utilize both salicylic and jasmonic acid in defense.
- Feature avirulent effectors and qualitative resistance genes.
Key Traits of Necrotrophs
- Feed on dead or dying cells; facultative with no haustoria.
- Broad host range, utilizing jasmonic acid in defense, and possessing specific toxins and necrotrophic effectors.
- Resistance genes can exhibit quantitative traits.
Role of Effectors
- Effectors are pathogen-produced molecules influencing host interactions;
- Loss of virulence factors in biotrophs leads to pathogenicity confirmation.
- Necrotrophs deploy host-specific toxins to facilitate infection, while hemibiotrophs often possess virulence effectors, revealing complexity in pathogen-host interactions.
Shift in Pathogen Classification
- With advancements in genomic studies, traditional trophic classifications are being reevaluated, leading to a more nuanced understanding of pathogen categories.
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Description
Explore the classification of various fungal pathogens and their definitions. Learn about different strategies for combating plant diseases on a global scale, including biosecurity and agronomy. This quiz covers key concepts related to plant pathology and disease management.
