Phytoplasmas are obligate intracellular parasites of plant phloem tissue and of the insect vectors that are involved in their plant-to-plant transmission. Phytoplasmas were discovered in 1967 by Japanese scientists who termed them mycoplasma-like organisms. Since their discovery, phytoplasmas have resisted all attempts at in vitro culture in any cell-free medium; routine cultivation in an artificial medium thus remains a major challenge. Phytoplasmas are characterized by the lack of a cell wall, a pleiomorphic or filamentous shape, a diameter normally less than 1 μm, and a very small genome.
Nicotiana glauca is a species of flowering plant in the tobacco genus Nicotiana of the nightshade family Solanaceae. It is known by the common name tree tobacco. Its leaves are attached to the stalk by petioles, and its leaves and stems are neither pubescent nor sticky like Nicotiana tabacum. It resembles Cestrum parqui but differs in the form of leaves and fusion of the outer floral parts. It grows to heights of more than two meters.
Citrus greening disease or yellow dragon disease is a disease of citrus caused by a vector-transmitted pathogen. The causative agents are motile bacteria, Liberibacter spp. The disease is transmitted by the Asian citrus psyllid, Diaphorina citri, and the African citrus psyllid, Trioza erytreae, also known as the two-spotted citrus psyllid. It has no known cure. It has also been shown to be graft-transmissible.
Nicotiana tabacum, or cultivated tobacco, is an annually grown herbaceous plant of the genus Nicotiana. N. tabacum is the most commonly grown species in the genus Nicotiana, as the plant's leaves are commercially harvested to be processed into tobacco for human use. The plant is tropical in origin, is commonly grown throughout the world, and is often found in cultivation. It grows to heights between 1 and 2 meters. Research is ongoing into its ancestry among wild Nicotiana species, but it is believed to be a hybrid of Nicotiana sylvestris, N. tomentosiformis, and possibly N. otophora.
Latakia tobacco is a sun-dried and smoke-cured tobacco product. It originated in Syria and is named after its major port city of Latakia, though large production has permanently moved to Cyprus due to varying and compounding sociopolitical issues within Syrian borders. It is in the family of fire-cured tobaccos in which the leaves are dried(cured) over burning hard wood. what sets Latakia apart from other fire-cured tobaccos is the use of heavy volumes of smoke from both dried and live material from aromatic woods.
Phomopsis cane and leaf spot occurs wherever grapes are grown. Phomopsis cane and leaf spot is more severe in grape-growing regions characterized by a humid temperate climate through the growing season. Crop losses up to 30% have been reported to be caused by Phomopsis cane and leaf spot.
Stemphylium solani is a plant pathogen fungus in the phylum Ascomycota. It is the causal pathogen for grey leaf spot in tomatoes and leaf blight in alliums and cotton, though a wide range of additional species can serve as hosts. Symptoms include white spots on leaves and stems that progress to sunken red or purple lesions and finally leaf necrosis. S. solani reproduces and spreads through the formation of conidia on conidiophores. The teleomorph name of Stemphyllium is Pleospora though there are no naturally known occurrences of sexual reproduction. Resistant varieties of tomato and cotton are common, though the pathogen remains an important disease in Chinese garlic cultivation.
Flavescence dorée is one of the most important and damaging phytoplasma diseases of the vine with the potential to threaten vineyards. The bacterial agent has recently been named Candidatus Phytoplasma vitis, and its vector is the leafhopper, Scaphoideus titanus. Infection may kill young vines and greatly reduce the productivity of old vines. It is classified as a phytoplasma disease belonging to the group generically termed grapevine yellows. Occurrences are in sporadic epidemics, and varieties vary in their sensitivity to it.
This article contains a list of tobacco cultivars and varieties, as well as unique preparations of the tobacco leaf involving particular methods of processing the plant.
Grapevine yellows (GY) are diseases associated to phytoplasmas that occur in many grape growing areas worldwide and are of still increasing significance. The most important grapevine yellows is flavescence dorée.
The common brown leafhopper is one of the most common species of Australian leafhoppers with a very wide host range. It is an important vector of several viruses and phytoplasmas worldwide. In Australia, phytoplasmas vectored by O. orientalis cause a range of economically important diseases including legume little leaf, tomato big bud, lucerne witches broom, potato purple top wilt, Australian lucerne and the insect is a possible vector of Australian grapevine yellows. O. orientalis also transmits Tobacco yellow dwarf virus to beans, causing bean summer death disease and to tobacco, causing tobacco yellow dwarf disease.
Texas Phoenix palm decline, or lethal bronzing, is a plant disease caused by a phytoplasma, Candidatus Phytoplasma palmae. It takes its name from the state it was first identified in and the palm genus, Phoenix, upon which it was first identified. It is currently found in parts of Florida and Texas.
Paeonia × suffruticosa is a name used for a group of cultivars of tree peonies that are the result of hybridisation with species exclusively belonging to the subsection Vaginatae. The common name used in China is mǔdān. Plants belonging to this group have been cultivated for millennia in China, initially only as a source of traditional Chinese medicine particularly the skin of its roots. Already early on the plant was also cultivated for its ornamental value, and it is highly revered in Chinese culture.
Sugarcane grassy shoot disease (SCGS), is associated with 'Candidatus Phytoplasma sacchari' which are small, pleomorphic, pathogenic mycoplasma that contribute to yield losses from 5% up to 20% in sugarcane. These losses are higher in the ratoon crop. A higher incidence of SCGS has been recorded in some parts of Southeast Asia and India, resulting in 100% loss in cane yield and sugar production.
CandidatusPhytoplasma fraxini is a species of phytoplasma, a specialized group of bacteria which lack a cell wall and attack the phloem of plants. This phytoplasma causes the diseases ash yellows and lilac witches' broom.
Little leaf of brinjal or eggplant is one of the most serious diseases of brinjal in the areas of its cultivation.
Mastrevirus is a genus of ssDNA viruses, in the family Geminiviridae. Mostly monocotyledonous plants serve as natural hosts. They are vectored by planthoppers. There are 45 species in this genus. Diseases associated with this genus include: maize streak virus: maize streak disease (MSD).
Milkweed yellows phytoplasma is a strain of phytoplasma in the class Mollicutes, a class of bacteria distinguished by the absence of a cell wall. The phytoplasma strain is denoted by the acronym MW1.
Candidatus Phytoplasma pruni is a species of phytoplasma in the class Mollicutes, a class of bacteria distinguished by the absence of a cell wall. The specific epithet pruni means "living on Prunus", emphasizing the fact that the phytoplasma is a parasite of various Prunus species, otherwise known as stone fruits. The phytoplasma is commonly called the X-disease phytoplasma.
Candidatus Phytoplasma palmicola is a phytoplasma first detected in Mozambique in 2007. A symptomology similar to coconut lethal yellowing disease (LYD) was found. This same disease was then found in Côte d’Ivoire. It was discovered by Harrison et al., 2014 to be due to a species nova which they named Candidatus Phytoplasma palmicola and assigned to novel Candidatus Phytoplasma subgroup 16SrXXII-B.
