Verticillium
Encyclopedia
Verticillium is a genus
of fungi in the division Ascomycota
, and are an anamorphic form of the Plectosphaerellaceae family. The genus used to include diverse groups comprising saprobes and parasites of higher plants, insects, nematodes, mollusc eggs and other fungi thus it can be seen that the genus used to have a wide ranging group of taxa characterised by simple but ill-defined characters. The genus, currently thought to contain 51 species, may be broadly divided into three ecologically based groups 1) mycopathogens 2) entomopathogens (Zare and Gams, 2001) and 3) plant pathogens and related saprotrophs (Barbara and Clewes, 2003). However, recently the genus has undergone some revision into which most entomopathogenic and mycopathogenic isolates fall into a new group called Lecanicillium. The genus now includes the plant pathogenic species V. dahliae, V. albo-atrum, V. nubilium, and V. tricorpus.
The better known species of Verticillium are, V. dahliae and V. albo-atrum cause a wilt
disease called Verticillium wilt
in more than 400 eudicot plant species.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of fungi in the division Ascomycota
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...
, and are an anamorphic form of the Plectosphaerellaceae family. The genus used to include diverse groups comprising saprobes and parasites of higher plants, insects, nematodes, mollusc eggs and other fungi thus it can be seen that the genus used to have a wide ranging group of taxa characterised by simple but ill-defined characters. The genus, currently thought to contain 51 species, may be broadly divided into three ecologically based groups 1) mycopathogens 2) entomopathogens (Zare and Gams, 2001) and 3) plant pathogens and related saprotrophs (Barbara and Clewes, 2003). However, recently the genus has undergone some revision into which most entomopathogenic and mycopathogenic isolates fall into a new group called Lecanicillium. The genus now includes the plant pathogenic species V. dahliae, V. albo-atrum, V. nubilium, and V. tricorpus.
The better known species of Verticillium are, V. dahliae and V. albo-atrum cause a wilt
Wilting
Wilting refers to the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells...
disease called Verticillium wilt
Verticillium wilt
Verticillium Wilt is a wilt disease of over 300 species of eudicot plants caused by one of two species of Verticillium fungus, V. dahliae and V. albo-atrum. Many economically important plants are susceptible including cotton, tomatoes, potatoes, eggplants, peppers and ornamentals, as well as others...
in more than 400 eudicot plant species.
Selected species
- Verticillium dahliaeVerticillium dahliaeVerticillium dahliae is a fungal plant pathogen. It causes verticillium wilt in many plant species, causing leaves to curl and discolor. It may cause death in some plants.- External links :* *...
Kleb.
- Verticillium albo-atrum Reinke & Berthold - Causes Verticillium Wilt or Maple Wilt. First identified from potatoes in Germany in 1870, this species attacks over 300 different cultivatedHorticultureHorticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
plants and can persist as a saprotrophic soil organism for more than 15 years. When infecting ornamental trees like mapleMapleAcer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
s, elmElmElms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...
s, aspenAspenPopulus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...
, ash, beechBeechBeech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
, catalpaCatalpaCatalpa, commonly called catalpa or catawba, is a genus of flowering plants in the trumpet vine family, Bignoniaceae, native to warm temperate regions of North America, the Caribbean, and East Asia....
, oakOakAn oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
and others, the first symptoms are midsummer wilting on one side of a tree or branch. The sapwood has greenish or brownish streaks, and the infection can take a few years to progress to the rest of the tree or move rapidly. The fungi universally move up the xylemXylemXylem is one of the two types of transport tissue in vascular plants. . The word xylem is derived from the Classical Greek word ξυλον , meaning "wood"; the best-known xylem tissue is wood, though it is found throughout the plant...
vessels. In fruit trees the infection is known as 'Black Heart' and is common in apricots and sometimes affects almond, peach, plum and avocado trees. This fungus also affects herbaceousHerbaceousA herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
ornamentals and vegetables like Chrysanthemum, mints, Lychnis, tomatoes, eggplants, okra, and rhubarb, causing wilting and death. Identification can be made by looking for one-celled conidia, hyalineHyalineThe term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
round to ellipsoid which are formed at the tips of whorlSpiralIn mathematics, a spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point.-Spiral or helix:...
ed branches. They are easily separated from the tips.
- NematodeNematodeThe nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
pathogens, previously in Verticillium, have now been placed in the new genus PochoniaPochoniaPochonia is a genus of fungi within the order Hypocreales and is described as anamorphic Metacordyceps; 8 species are currently described. Previously placed in the genus Verticillium, these fungi are known to be pathogenic to nematodes and are being developed and commercialized as biological...
.
- All insect pathogens have been placed in the new genus LecanicilliumLecanicilliumLecanicillium is a genus of fungi within the order Hypocreales and is described as anamorphic Cordycipitaceae; 21 species are currently described. These are entomopathogenic fungus species, that were previously widely known as Verticillium lecanii Viegas .The IndexFungorum records the following...
. An approved name of Verticillium lecanii (Zimmerman) Viegas is now Lecanicillium lecaniiLecanicillium lecaniiLecanicillium lecanii is now an approved name of an entomopathogenic fungus species, that was previously widely known as Verticillium lecanii Viegas), but is now understood to be an anamorphic form in the Cordyceps group of genera in the Clavicipitaceae . It now appears that isolates formerly...
although this now also includes: L. attenuatum, L. longisporum, L. muscarium and L. nodulosum.