Dickeya dadantii is a gram-negative bacillus that belongs to the family Pectobacteriaceae. It was formerly known as Erwinia chrysanthemi but was reassigned as Dickeya dadantii in 2005. Members of this family are facultative anaerobes, able to ferment sugars to lactic acid, have nitrate reductase, but lack oxidases. Even though many clinical pathogens are part of the order Enterobacterales, most members of this family are plant pathogens. D. dadantii is a motile, nonsporing, straight rod-shaped cell with rounded ends, much like the other members of the genus, Dickeya. Cells range in size from 0.8 to 3.2 μm by 0.5 to 0.8 μm and are surrounded by numerous flagella (peritrichous).
This is a glossary of some of the terms used in phytopathology.
Xanthomonas campestris is a gram-negative, obligate aerobic bacterium that is a member of the Xanthomonas genus, which is a group of bacteria that are commonly known for their association with plant disease. The species is considered to be dominant amongst its genus, as it originally had over 140 identified pathovars and has been found to infect both monocotyledonous and dicotyledonous plants of economical value with various plant diseases. This includes "black rot" in cruciferous vegetables, bacterial wilt of turfgrass, bacterial blight, and leaf spot, for example.
Pseudomonas syringae is a rod-shaped, Gram-negative bacterium with polar flagella. As a plant pathogen, it can infect a wide range of species, and exists as over 50 different pathovars, all of which are available to researchers from international culture collections such as the NCPPB, ICMP, and others.
Pseudomonas savastanoi is a gram-negative plant pathogenic bacterium that infects a variety of plants. It was once considered a pathovar of Pseudomonas syringae, but following DNA-relatedness studies, it was instated as a new species. It is named after Savastano, a worker who proved between 1887 and 1898 that olive knot are caused by bacteria.
Ralstonia solanacearum is an aerobic non-spore-forming, Gram-negative, plant pathogenic bacterium. R. solanacearum is soil-borne and motile with a polar flagellar tuft. It colonises the xylem, causing bacterial wilt in a very wide range of potential host plants. It is known as Granville wilt when it occurs in tobacco. Bacterial wilts of tomato, pepper, eggplant, and Irish potato caused by R. solanacearum were among the first diseases that Erwin Frink Smith proved to be caused by a bacterial pathogen. Because of its devastating lethality, R. solanacearum is now one of the more intensively studied phytopathogenic bacteria, and bacterial wilt of tomato is a model system for investigating mechanisms of pathogenesis. Ralstonia was until recently classified as Pseudomonas, with similarity in most aspects, except that it does not produce fluorescent pigment like Pseudomonas. The genomes from different strains vary from 5.5 Mb up to 6 Mb, roughly being 3.5 Mb of a chromosome and 2 Mb of a megaplasmid. While the strain GMI1000 was one of the first phytopathogenic bacteria to have its genome completed, the strain UY031 was the first R. solanacearum to have its methylome reported. Within the R. solanacearum species complex, the four major monophyletic clusters of strains are termed phylotypes, that are geographically distinct: phylotypes I-IV are found in Asia, the Americas, Africa, and Oceania, respectively.
Xanthomonas is a genus of bacteria, many of which cause plant diseases. There are at least 27 plant associated Xanthomonas spp., that all together infect at least 400 plant species. Different species typically have specific host and/or tissue range and colonization strategies.
Halo blight of bean is a bacterial disease caused by Pseudomonas syringae pv. phaseolicola. Halo blight’s pathogen is a gram-negative, aerobic, polar-flagellated and non-spore forming bacteria. This bacterial disease was first discovered in the early 1920s, and rapidly became the major disease of beans throughout the world. The disease favors the places where temperatures are moderate and plentiful inoculum is available.
Clavibacter michiganensis is an aerobic non-sporulating Gram-positive plant pathogenic actinomycete of the genus Clavibacter. Clavibacter michiganensis has several subspecies. Clavibacter michiganensis subsp. michiganensis causes substantial economic losses worldwide by damaging tomatoes and potatoes.
Xanthomonas vasicola pv. vasculorum (Xvv) is a gram-negative rod-shaped bacterium which has a single polar flagellum. It is a plant pathogen, causing both bacterial leaf streak of maize (corn) and sugarcane gumming disease. One outbreak in eucalyptus has been reported. Under experimental conditions it can infect sorghum, oats and some grass species. It is not currently a quarantine pathogen in any country, but it has already spread outside its native range and is highly adaptable to different environments.
Bacterial wilt is a complex of diseases that occur in plants such as Cucurbitaceae and Solanaceae and are caused by the pathogens Erwinia tracheiphila, a gram-negative bacterium, or Curtobacterium flaccumfaciens pv. flaccumfaciens, a gram-positive bacterium. Cucumber and melon plants are most susceptible, but squash, pumpkins, and gourds may also become infected.
Black rot, caused by the bacterium Xanthomonas campestris pv. campestris (Xcc), is considered the most important and most destructive disease of crucifers, infecting all cultivated varieties of brassicas worldwide. This disease was first described by botanist and entomologist Harrison Garman in Lexington, Kentucky, US in 1889. Since then, it has been found in nearly every country in which vegetable brassicas are commercially cultivated.
Bacterial soft rots are caused by several types of bacteria, but most commonly by species of gram-negative bacteria, Erwinia, Pectobacterium, and Pseudomonas. It is a destructive disease of fruits, vegetables, and ornamentals found worldwide, and affects genera from nearly all the plant families. The bacteria mainly attack the fleshy storage organs of their hosts, but they also affect succulent buds, stems, and petiole tissues. With the aid of special enzymes, the plant is turned into a liquidy mush in order for the bacteria to consume the plant cell's nutrients. Disease spread can be caused by simple physical interaction between infected and healthy tissues during storage or transit. The disease can also be spread by insects. Control of the disease is not always very effective, but sanitary practices in production, storing, and processing are something that can be done in order to slow the spread of the disease and protect yields.
Xanthomonas campestris pv. vesicatoria is a bacterium that causes bacterial leaf spot (BLS) on peppers and tomatoes. It is a gram-negative and rod-shaped. It causes symptoms throughout the above-ground portion of the plant including leaf spots, fruit spots and stem cankers. Since this bacterium cannot live in soil for more than a few weeks and survives as inoculum on plant debris, removal of dead plant material and chemical applications to living plants are considered effective control mechanisms.
Bacterial wilt of turfgrass is the only known bacterial disease of turf. The causal agent is the Gram negative bacterium Xanthomonas campestris pv. graminis. The first case of bacterial wilt of turf was reported in a cultivar of creeping bentgrass known as Toronto or C-15, which is found throughout the midwestern United States. Until the causal agent was identified in 1984, the disease was referred to simply as C-15 decline. This disease is almost exclusively found on putting greens at golf courses where extensive mowing creates wounds in the grass which the pathogen uses in order to enter the host and cause disease.
Bacterial wilt of carnations is a bacterial disease caused by the plant pathogen Paraburkholderia caryophylli. Previously named Pseudomonas caryophilli, the pathogen is an aerobic gram negative bacteria known for only being capable of entering its host through wounds. Once inside the host, it colonizes the vascular system and roots causing symptoms such as, internal stem cracking, yellowing of the leaves, wilting, and the development of cankers. As a bacterial disease, bacterial wilt of carnations can also be characterized by signs such as bacterial streaming, and bacterial ooze.
Xanthomonas oryzae pv. oryzae is a bacterial pathovar that causes a serious blight of rice, other grasses, and sedges.
Bacterial blight of soybean is a widespread disease of soybeans caused by Pseudomonas syringaepv. glycinea.
Clavibacter insidiosus is a species of Clavibacter. It causes bacterial wilt, with its most notable host being Medicago sativa (alfalfa). Other species in the Medicago genus are also known to be hosts such as Medicago falcata. Additionally, Lotus corniculatus, Melilotus alba, Onobrychis viciifolia, and Trifolium sp. are known hosts.
Ralstonia pseudosolanacearum is a soil-borne bacterium. It is a vascular phytopathogen that infects host plants through the root system causing wilting disease that causes loss in a wide range of crops. R. pseudosolanacearum is Gram negative and was originally identified as Ralstonia solanacearum, however, in 2014 Safni et al. proposed a taxonomic revision of the Ralstonia solanacearum species complex to reclassify phylotype strains, including R. pseudosolanacearum.
