Verticillium

A Microbial Biorealm page on the phylum Verticillium

Verticillium sp. well differentiated and erect conidiophores, verticillately branched over most of their length, bearing whorls of slender awl-shaped divergent phialides. Conidia are hyaline or brightly coloured, mostly one-celled, and are usually borne in slimy heads (glioconidia). [1]

Classification

Higher order taxa

Division Eucaryota, Kingdom Fungi, Phylum Ascomycota, Class Incertae sedis

Species

Verticillium dahliae
Verticillium lecanii
Verticillium albo-atrum

Description and Significance

One-sided wilt and death of potato leaves caused by Verticillium spp. by: [2]

Typical V-shaped lesions on tomato leaves associated with Verticillium wilt. by: [3]

Verticillium is a filamentous fungus that inhabits decaying vegetation and soil. Some Verticillium species may be pathogenic to arthropods, plants, and other fungi. It is commonly considered as a contaminant. Verticillium may very rarely cause human disease.(1)

Verticillium is also a genus of fungi of Ascomycota. This genus has three ecologically based group: mycopathogens, entomopathogens, and plant pathogens and related saprophytes. The commonly known species of Verticillium fall within the plant pathogens group.

Verticillim dehliae and Verticillim albo-atrum cause wilt diseases, which refers to loss of rigidity of non-woody parts of plants, in plants such as cotton, potatos, peppers, eggplants, and tomatoes. Because these fungi are soil-borne and can infect so many different plant species, Verticillium wilt is difficult to control. (4)

Symptoms of Verticillium wilt on maple: the left half of the tree appears diseased, while the right half appears healthy. (Photo by R. J. Stipes). by: [4]

Microscopic Features

"Septate hyaline hyphae, conidiophores, phialides, and conidia are observed. Conidiophores are hyaline, simple or branched. The branching of the conidiophores occurs in whorls (=verticillate; resembling spokes in a wheel from a central axis) at several levels. Conidiophores bear the phialides. Phialides are very long and are also arranged in verticils (whorls) around the conidiophore. Verticils may be disrupted in slide culture. The apices of the phialides are pointed. Conidia (2-13µm in length) are hyaline or brightly colored, one-celled, and oval to pyriform in shape. They are solitary or form clusters in sticky heads at the tips of the phialides." (1)(3)(6)

Pathogenicity and Clinical Significance

Verticillium has been reported as a possible cause of keratitis in humans. (2)(3)

References

(1)http://www.doctorfungus.org/thefungi/verticillium.htm

(2)Larone, D. H. 1995. Medically Important Fungi - A Guide to Identification, 3rd ed. ASM Press, Washington, D.C.

(3)Sutton, D. A., A. W. Fothergill, and M. G. Rinaldi (ed.). 1998. Guide to Clinically Significant Fungi, 1st ed. Williams & Wilkins, Baltimore.

(4)http://www.ext.vt.edu/pubs/plantdiseasefs/450-619/450-619.html

(5)Larone, D. H. 1995. Medically Important Fungi - A Guide to Identification, 3rd ed. ASM Press, Washington, D.C.

(6)St-Germain, G., and R. Summerbell. 1996. Identifying Filamentous Fungi - A Clinical Laboratory Handbook, 1st ed. Star Publishing Company, Belmont, California.