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Plant pathogens, organisms that cause infectious plant diseases, include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. [2] In most plant pathosystems, virulence depends on hydrolases and enzymes that degrade the cell wall.
Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). [1] Organisms that cause infectious disease include fungi , oomycetes , bacteria , viruses , viroids , virus -like organisms, phytoplasmas , protozoa , nematodes and parasitic plants . [ 2 ]
The discovery of plant viruses causing disease is often accredited to A. Mayer (1886) working in the Netherlands demonstrated that the sap of mosaic obtained from tobacco leaves developed mosaic symptom when injected in healthy plants. However the infection of the sap was destroyed when it was boiled. He thought that the causal agent was bacteria.
The symptoms appeared on plants onto which pieces from affected plants had been budded—indicating that the disease was caused by a transmissible pathogenic agent. A fungus or bacterium could not be found consistently associated with symptom-bearing plants, however, and therefore, it was assumed the disease was caused by a virus. Despite ...
Plants can show many signs or physical evidence of fungal, viral or bacterial infections. This can range from rusts or molds to not showing anything at all when a pathogen invades the plant (occurs in some viral diseases in plants). [9] Symptoms which are visible effects of diseases on the plant consist of changes in color, shape or function. [9]
Citrus blight, caused by an unknown agent, infects all citrus scions. Fire blight of pome fruits, caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., is the most severe disease of pear and also is found in apple and raspberry, among others. Bacterial leaf blight of rice, caused by the bacterium Xanthomonas oryzae (Uyeda ...
bacterial streaming. bactericide. bacteriocin. bacteriophage. bacterium (pl. bacteria) bactericide. basal knob (syn. stylet knob) basidiocarp (syn. basidioma) Basidiomyctes. The Division Basidiomycota is a large taxon within the Kingdom Fungi that includes those species that produce spores in a club-shaped structure called a basidium. basidiospore
Important diseases caused by phytomyxeans include club root in cabbage and its relatives, and powdery scab in potatoes. [4] These are caused by species of Plasmodiophora and Spongospora, respectively. [5] The vegetative form is a multinucleate cell, called a plasmodium. This ultimately divides to form new spores, which are released when the ...