Milkweed yellows phytoplasma is a strain of

phytoplasma 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-li ...

in the

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

Mollicutes Mollicutes is a class of bacteria distinguished by the absence of a cell wall and its peptidoglycan. The word "Mollicutes" is derived from the Latin ' (meaning "soft" or "pliable"), and ' (meaning "skin"). Individuals are very small, typically on ...

, a class of

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

distinguished by the absence of a

cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...

. The phytoplasma strain is denoted by the acronym MW1. Like all phytoplasmas, milkweed yellows phytoplasma is an

obligate intracellular parasite Intracellular parasites are microparasites that are capable of growing and reproducing inside the cells of a host. They are also called intracellular pathogens. Types There are two main types of intracellular parasites: Facultative and Obligate ...

, that is, it can not live outside of host cells. It spreads by means of an insect

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

, the identity of which is unknown. In general, phytoplasmas spread via

leafhoppers Leafhopper is the common name for any species from the family Cicadellidae: based on the type genus ''Cicadella''. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind ...

and other sap-sucking insects that transmit the

pathogen In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...

from one host plant to another.

Taxonomy

In 1994, two strains of phytoplasmas that infect the common milkweed ''

Asclepias syriaca ''Asclepias syriaca'', commonly called common milkweed, butterfly flower, silkweed, silky swallow-wort, and Virginia silkweed, is a species of flowering plant. It is native to southern Canada and much of the United States east of the Rocky Moun ...

'' (denoted MW1 and MW2) were shown to be members of the X-disease group (16Sr group III). Milkweed yellows phytoplasma (MW1) was later found to be a ' ''Candidatus'' Phytoplasma pruni'-related strain of phytoplasma belonging to subgroup F (16SrIII-F). Other phytoplasmas in subgroup 16SrIII-F include ''Vaccinium'' witches' broom phytoplasma (VAC, VacWB) and potato purple top phytoplasma (AKpot7). , milkweed yellows phytoplasma has not been formally described.

Milkweed yellows

Milkweed yellows is an

infectious disease An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

milkweed ''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to huma ...

s caused by the milkweed yellows phytoplasma. Other diseases caused by

s in subgroup 16SrIII-F include ''Vaccinium'' witches' broom, potato purple top, and a greening disorder of ''Trillium grandiflorum'' and other ''Trillium'' species.

Hosts

The common milkweed ''

'' and the periwinkle ''

Catharanthus roseus ''Catharanthus roseus'', commonly known as bright eyes, Cape periwinkle, graveyard plant, Madagascar periwinkle, old maid, pink periwinkle, rose periwinkle, is a perennial species of flowering plant in the family Apocynaceae. It is native and en ...

'' are known plant hosts for milkweed yellows phytoplasma. The insect host species for milkweed yellows is not known.

Bibliography

References

External links