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Life cycle of the black rot pathogen, the gram negative bacterium Xanthomonas campestris pathovar campestris. Plant pathology or phytopathology is the scientific study of plant diseases caused by pathogens (infectious organisms) and environmental conditions (physiological factors). [1]
colonization of a niche in the host (this includes movement towards and attachment to host cells) [1] [2] immunoevasion, evasion of the host's immune response [1] [2] [3] immunosuppression, inhibition of the host's immune response (this includes leukocidin-mediated cell death) [1] entry into and exit out of cells (if the pathogen is an ...
Most pathogens instead exhibit a high degree of host-specificity. Non-host plant species are often said to express non-host resistance. The term host resistance is used when a pathogen species can be pathogenic on the host species but certain strains of that plant species resist certain strains of the pathogen species. The causes of host ...
Colonization Some virulent bacteria produce special proteins that allow them to colonize parts of the host body. Helicobacter pylori is able to survive in the acidic environment of the human stomach by producing the enzyme urease. Colonization of the stomach lining by this bacterium can lead to gastric ulcers and cancer.
Many plant pathogens produce virulence factors, or effectors, that modulate or interfere with normal host processes to the benefit of the pathogens. The first phytoplasmal virulence factor, a secreted protein termed “tengu-su inducer” (TENGU; C0H5W6 ), was identified in 2009 from a phytoplasma causing yellowing of onions .
In 1987, it was proposed that bacterial strains showing >70% DNA·DNA re-association and sharing characteristic phenotypic traits should be considered to be strains of the same species. [46] The diversity within pathogen genomes makes it difficult to identify the total number of genes that are associated within all strains of a pathogen species ...
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 ]
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]