genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
s (roundworms) in the
order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
Aphelenchida
Aphelenchida is a moderately large order of nematodes. Aphelenchida have a stylet for feeding and a very prominent median bulb in the oesophagus. They are cosmopolitan. Some are associated with insects, and may be ectoparasites or endoparasit ...
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...
, with two species, the red ring nematode (''B. cocophilus'') and the
pine wood nematode
''Bursaphelenchus xylophilus'', commonly known as pine wood nematode or pine wilt nematode (PWN), is a species of nematode that infects trees in the ''Pinus'' genus of coniferous trees and causes the disease pine wilt.pests
PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...
of
coconut palms
The coconut tree (''Cocos nucifera'') is a member of the palm tree family (Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, the seed, or the f ...
and of
pine trees
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...
, respectively. Given that ''Bursaphelenchus'' species are usually hard to distinguish from one another except by trained nematologists with access to
microscope
A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
s or
DNA sequence
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
analysis, the entire genus is put under
quarantine
A quarantine is a restriction on the movement of people, animals and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have been ...
in some countries. Where this is not the case however, these nematodes are becoming established as
model organism
A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...
s for nematode
developmental biology
Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and di ...
,
ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...
and
genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...
.
As of 2009, there are about 70 to 90 species in the genus. New taxa are described frequently.
Ecology
''Bursaphelenchus'' contains a single described
hermaphroditic
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
Many taxonomic groups of animals (mostly invertebrates) do not have separ ...
species, ''okinawaensis'', and over 100 described
gonochoristic
In biology, gonochorism is a sexual system where there are only two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric.
Gonochorism c ...
species. They inhabit
soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...
or decaying wood, feeding on the wood itself or
fungal
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...
hypha
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Structure
A hypha consists of one or ...
e growing in it, such as those of grey mould (''Botrytis cinerea''). They are sometimes beneficial when they reduce the fungal load inside the wood, but when they consume the plant tissue they are known to cause the death of living trees.
These nematodes are phoretic, dispersed between trees when their
dauer larva Dauer (German "''die Dauer''", English "the enduring", "the duration" in the meaning of "a length of time",) describes an alternative developmental stage of nematode worms, particularly rhabditids including '' Caenorhabditis elegans'', whereby the ...
e are transported by
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s. Species involved include
bark beetle
A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the ...
s,
weevil
Weevils are beetles belonging to the Taxonomic rank, superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and Herbivore, herbivorous. Approximately 97,000 species of weevils are known. They b ...
bee
Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...
s. The process of dauer larva formation is not well understood, but it is of research interest because it is significant in the
epidemic
An epidemic (from Ancient Greek, Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time.
Epidemics ...
s of plant diseases caused by these nematodes, such as pine wilt.
Selected species
''Bursaphelenchus'' includes:
* ''
Bursaphelenchus abietinus
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the red ring nematode (''B. cocophilus'') and the pine wood nematode (''B. xylo ...
Bursaphelenchus borealis
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the red ring nematode (''B. cocophilus'') and the pine wood nematode (''B. xylo ...
Bursaphelenchus cocophilus
The red ring disease of coconuts and Elaeis guineensis, African oil palms is caused by the nematode ''Bursaphelenchus cocophilus''. It is also identified in literature with an alternative scientific name ''Rhadinaphelenchus cocophilus''. The com ...
Bursaphelenchus hildegardae
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the red ring nematode (''B. cocophilus'') and the pine wood nematode (''B. xylo ...
Bursaphelenchus paracorneolus
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order (biology), order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the Bursaphelenchus cocophilus, red ring nematode (''B. cocophil ...
Bursaphelenchus sinensis
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the red ring nematode (''B. cocophilus'') and the pine wood nematode (''B. xylo ...
Bursaphelenchus thailandae
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the red ring nematode (''B. cocophilus'') and the pine wood nematode (''B. xylo ...
Bursaphelenchus xylophilus
''Bursaphelenchus xylophilus'', commonly known as pine wood nematode or pine wilt nematode (PWN), is a species of nematode that infects trees in the ''Pinus'' genus of coniferous trees and causes the disease pine wilt.Bursaphelenchus yongensis''