Pseudomonas cannabina | |
---|---|
Scientific classification | |
Domain: | Bacteria |
Phylum: | Proteobacteria |
Class: | Gammaproteobacteria |
Order: | Pseudomonadales |
Family: | Pseudomonadaceae |
Genus: | Pseudomonas |
Species: | P. cannabina |
Binomial name | |
Pseudomonas cannabina (ex Šutic and Dowson 1959) Gardan et al. 1999 | |
Synonyms | |
Pseudomonas cannabinaŠutic and Dowson 1959 Contents |
Pseudomonas cannabina is a gray, Gram-negative, fluorescent, motile, flagellated, aerobic bacterium that causes leaf and stem rot of hemp ( Cannabis sativa ), [1] from which it derives its name. It was formerly classified as a pathovar of Pseudomonas syringae , but following ribotypical analysis, it was reinstated as a species. [2] The type strain is CFBP 2341.[ citation needed ]
Pseudomonas cannabina was once classified as Pseudomonas syringae pv. cannabina, but after extensive DNA testing of several P. syringae pathovars, P. cannabina was declared its own species, known as genomospecies 9. [2] P. cannabina turns out to have at least two pathovars of its own: P. cannabina pv. cannabina and P. cannabina pv. alisalensis (formerly known as P. syringae pv. alisalensis). [3] This distinction is supported by a difference in host range between the pathovars as well as physiological differences including carbon source utilization, bacteriophage sensitivity, and pigment production. [4] P. cannabina pv. cannabina has only been shown to be pathogenic on Cannabis sativa, while P. cannabina pv. alisalensis has been shown to be pathogenic on broccoli, broccoli raab, radish, arugula, and oat, and probably infects other crucifers and grains though identification is difficult given the genomic confusion in the literature. [3] [4] For example, P. cannabina pv. alisalensis has also been shown through Multi-Locus Sequence Analysis to be responsible for bacterial blights in crucifers formerly associated with the B70 strain of Pseudomonas syringae maculicola identified on radish in Wisconsin in 1965. [4]
In crucifers, P. cannabis pv. alisalensis causes a blight on the leaves (appearing similarly to those caused by P. syringae as well as the common fungal disease Brown Leaf Spot) [5] [6] [7] [8] [9] The infection can be diagnosed by the following:[ citation needed ]
Overwatering and stress increase plant susceptibility.[ citation needed ]
In Cannabis, P. cannabina pv. cannabina causes stem and leaf rot of both industrial (hemp) and horticultural plants, producing similar symptoms to those observed in crucifers. Despite the fact that Pseudomonas bacterial blight is the most commonly documented disease of cannabis plants, [9] [10] the chlorotic lesions are often mistaken by horticultural growers for those of overwatering, nitrogen deficiency, phosphorus deficiency, or Septoria. [11] [12]
Bacterial blight caused by P. cannabina pv. alisalensis has been reported in Greece, Germany, Australia, Japan, and several regions of the US including the Midwest, South, and Pacific Coast. Though some of these identifications were mislabeled as P. syringae pv. alisalensis, the indication that P. cannabina pv. alisalensis has a wide, intercontinental distribution is clear. [5] [6] [7] [8] The distribution of P. cannabina pv. cannabina is less obvious, because the fluctuating legal status of the host plant creates difficulty in researching the disease, though it is frequently referred to as a common bacterial blight in the available cannabis horticulture literature.[ citation needed ]
Bacterial blight in both hemp and crucifers is encouraged by cool, wet conditions in the range of 12–28 °C (54–82 °F), and is spread by water through irrigation of crops with a potential for seed transmission as well. [9] [13] [14]
Humans have cultivated Cannabis sativa for thousands of years. [15] Recently however, the legalization of cannabis for both recreational and medical use has come into the public eye in the US, as several states have moved to legalize the cultivation, research, and use of the plant. This burgeoning industry places a significant economic importance on diseases of the hemp plant in the global market, and education and control concerning possible crop impacts will be crucial as cannabis enters the mainstream economy. Globally, marijuana use, cultivation, and stigma differs from place to place, but the identification of geographic range and control measures for P. cannabina pv. cannabina will become more important as the legal status of hemp changes and widespread cultivation increases. While the virulence of P. cannabina pv. cannabina has not yet been studied extensively, a single square foot of marijuana plants can yield up to 6 ounces of sellable material which translates to a market value of roughly USD $1800/sq ft, depending on strain and local market prices,[ citation needed ] so even a small overall yield loss due to blight has the potential to be financially devastating. Hemp grown for industrial use has a significantly lower value/area ratio but in a large-scale production situation, loss from disease could still be devastating.[ citation needed ]
Pseudomonas cannabina pv. alisalensis is already of great economic importance, as it affects many already-legal cruciferous horticultural crops worldwide and can severely damage or destroy the market value of an afflicted crop. [5] [6] [7] [8]
A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore of major economic importance in agriculture and horticulture. Their causes include such a wide range of organisms as fungi, bacteria, mycoplasmas and viruses. The majority of canker-causing organisms are bound to a unique host species or genus, but a few will attack other plants. Weather and animals can spread canker, thereby endangering areas that have only slight amount of canker.
Phytotoxins are substances that are poisonous or toxic to the growth of plants. Phytotoxic substances may result from human activity, as with herbicides, or they may be produced by plants, by microorganisms, or by naturally occurring chemical reactions.
Xanthomonas campestris is bacterial species that causes a variety of plant diseases, including "black rot" in cruciferous vegetables and bacterial wilt of turfgrass.
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 avellanae is a Gram-negative plant pathogenic bacterium. It is the causal agent of bacterial canker of hazelnut. Based on 16S rRNA analysis, P. avellanae has been placed in the P. syringae group. This species was once included as a pathovar of Pseudomonas syringae, but following DNA-DNA hybridization, it was instated as a separate species. Following ribotypical analysis Pseudomonas syringae pv. theae was incorporated into this species.
Pseudomonas cichorii is a Gram-negative soil bacterium that is pathogenic to plants. It has a wide host range, and can have an important economical impact on lettuce, celery and chrysanthemum crops. P. cichorii was first isolated on endives, from which it derives its name. It produces 6-aminopenicillanic acid. Based on 16S rRNA analysis, P. cichorii has been placed in the P. syringae group.
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.
Pseudomonas viridiflava is a fluorescent, Gram-negative, soil bacterium that is pathogenic to plants. It was originally isolated from the dwarf or runner bean, in Switzerland. Based on 16S rRNA analysis, P. viridiflava has been placed in the P. syringae group. Following ribotypical analysis misidentified strains of Pseudomonas syringae pv. ribicola and Pseudomonas syringae pv. primulae were incorporated into this species. This pathogen causes bacterial blight of Kiwifruit.
Pseudomonas amygdali is a Gram-negative plant pathogenic bacterium. It is named after its ability to cause disease on almond trees. Different analyses, including 16S rRNA analysis, DNA-DNA hybridization, and MLST clearly placed P. amygdali in the P. syringae group together with the species Pseudomonas ficuserectae and Pseudomonas meliae, and 27 pathovars of Pseudomonas syringae/Pseudomonas savastanoi, constituting a single, well-defined phylogenetic group which should be considered as a single species. This phylogenetic group has not been formally named because of the lack of reliable means to differentiate it phenotipically from closely related species, and it is currently known as either genomospecies 2 or phylogroup 3. When it is formally named, the correct name for this new species should be Pseudomonas amygdali, which takes precedence over all the other names of taxa from this group, including Pseudomonas savastanoi, which is and inadequate and confusing name whose use is not recommended.
Pseudomonas tremae is a white, Gram-negative, non-fluorescent, motile, flagellated, aerobic bacterium that infects Trema orientalis, from which it derives its name. It was formerly classified as a pathovar of Pseudomonas syringae, but following ribotypical analysis, it was instated as a species. The type strain is CFBP 3229.
Pseudomonas coronafaciens is a Gram-negative bacterium that is pathogenic to several plant species. Following ribotypical analysis several pathovars of Pseudomonas syringae were incorporated into this species.
Xanthomonas is a genus of Proteobacteria, 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.
Septoria cannabis is a species of plant pathogen from the genus Septoria that causes the disease commonly known as Septoria leaf spot. Early symptoms of infection are concentric white lesions on the vegetative leaves of cannabis plants, followed by chlorosis and necrosis of the leaf until it is ultimately overcome by disease and all living cells are then killed. Septoria, which is an ascomycete and pycnidia producing fungus, has been well known to attack Solanaceae and Cucurbitaceae species as well as many tree species. This genus is known to comprise over 1,000 species of pathogens, each infecting a specific and unique host.
'Pseudomonas tomato' 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 recognized as a separate species and several other former P. syringae pathovars were incorporated into it. Since no official name has yet been given, it is referred to by the epithet 'Pseudomonas tomato' .
'Pseudomonas helianthi' 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 recognized as a separate species and P. syringae pv. tagetis was incorporated into it, as well. Since no official name has yet been given, it is referred to by the epithet 'Pseudomonas helianthi' .
Bleeding canker of horse chestnut is a common canker of horse chestnut trees that is known to be caused by infection with several different pathogens.
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.
Xanthomonas oryzae pv. oryzae is a bacterial pathovar which causes a serious blight of rice, other grasses and sedges.
Bacterial blight of soybean is a widespread disease caused by Pseudomonas syringaepv. glycinea.