Cochliobolus sativus

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Cochliobolus sativus
Cochliobolus sativus - Lindsey.jpg
Symptoms on a wheat leaf
Scientific classification
Kingdom: Fungi
Phylum: Ascomycota
Class: Ascomycetes
Order: Pleosporales
Family: Pleosporaceae
Genus: Cochliobolus
Species: C. sativus
Binomial name
Cochliobolus sativus
(S. Ito & Kurib.) Drechsler ex Dastur (1942)
Synonyms

Bipolaris californica (Mackie & G.E. Paxton) Gornostaĭ (1978)
Bipolaris sorokiniana (Sacc.) Shoemaker (1959)
Drechslera sorokiniana (Sacc.) Subram. & B.L. Jain (1966)
Helminthosporium acrothecioides Lindf. (1918)
Helminthosporium californicum Mackie & G.E. Paxton (1923)
Helminthosporium sativum Pammel, C.M. King & Bakke (1910)
Helminthosporium sorokinianum Sacc. (1890)
Ophiobolus sativus S. Ito & Kurib. (1929)

The fungus Cochliobolus sativus is the teleomorph (sexual stage) of Bipolaris sorokiniana (anamorph) which is the causal agent of a wide variety of cereal diseases. The pathogen can infect and cause disease on the root (where it is known as common root rot), leaf and stem, and head tissue. C.sativus is extremely rare in nature and thus it is the asexual or anamorphic stage which causes infections. The two most common diseases caused by B.sorokiniana are spot blotch and common root rot, mainly on wheat and barley crops.

Identification[edit]

The mycelium of B.sorokiniana is usually deep olive-brown. New cultures produce abundant simple conidiophores, which may be single or clustered and measure 6-10 x 110-220 μm with septations. Conidia develop laterally from pores beneath each conidiophore setpum. Conidia are olive-brown and ovate to oblong, with rounded ends and a prominent basal scar. They measure 15-28 x 40-120 μm and are 3- to 10- septate. Some may be slightly curved. Their walls are smooth and noticeably thickened at the septa.[1]

The sexual state (C.sativus), when formed in culture, is in the form of black, globose pseudothecia 300-400 μm in diameter, with erect beaks 50-200 μm long. Asci are clavate and measure 20-35 x 150-250 μm. Ascospores are hyaline, uniformly filamentous, and spirally flexed within asci. They measure 5-10 x 200-250 μm and are 4- to 10-septate.[1]

Host species[edit]

Agropyron cristatum1, Allium sp. 1, Alopecurus pratensis1, Aneurolepidium chinense1, Avena sativa1

Bromus inermis1, B. marginatus1, B. willdenowii1

Calluna vulgaris1, Chloris gayana1, Cicer arietinum1, Clinelymus dahuricus1, C. sibiricus1, Cynodon dactylon1, C. transvaalensis1

Dactylis glomerata1

Echinochloa crus-galli1, Elymus junceus1

Festuca sp. 1

Guzmania sp. 1

Hordeum brevisubulatum1, H. distichon1, H. sativum var. hexastichon1, H. vulgare1, H. vulgare var. hexastichon1

Lablab purpureus1, Linum usitatissimum1, Lolium multiflorum1

Pennisetum typhoides1

Roegneria semicostata1

Saccharum sp. 1, Secale cereale1, Setaria italica1, Sorghum sp. 1

Taraxacum kok-saghyz1, Trisetum aestivum1, Triticum aestivum1, T. secale1, T. turgidum subsp. durum, T. vulgare1’’

Zea mays1

Notes[edit]

1. USDA ARS Fungal Database

Geographical distribution[edit]

Cochliobolus sativus has a world-wide distribution.

Geographical distribution
Africa Kenya,1 Malawi,1 Sudan,1 South Africa, 1 Tanzania, 1 Zimbabwe1
Australasia Australia,1 China, 1 Korea, 1 India, 1 Indonesia, 1 New Zealand,1 Papua New Guinea,1 Taiwan, 1 Thailand1
Central America Cuba, 1 Mexico, 1 Nicaragua1
Europe Austria, 1 Belgium, 1 Czechoslovakia, 1 Denmark, 1 Germany, 1 Greece, 1 Hungary, 1 Italy, 1 Poland, 1 Scotland, 1 United Kingdom, 1 USSR
North America Canada (Alberta, 1 Manitoba, 1 Saskatchewan1) US (Indiana, 1 Kansas, 1 Minnesota, 1 Montana, 1 New York, 1 North Dakota, 1 South Dakota, 1 Utah, 1 Virginia1)
South America Argentina, 1 Brazil1

Notes[edit]

1. USDA ARS Fungal Database

Main diseases[edit]

Common root rot (barley); Common root rot (wheat); spot blotch (barley); Spot blotch (wheat)

Spot blotch of wheat[edit]

This is most important disease in non-tradition wheat growing areas. The B. sorokiniana comes with Pyrenophora tritici-repentis and causes millions of tons of wheat loss each year. The symptoms are blotch as well as induced senescence due to premature chlorophyll losses Rosyara et al., 2007[dead link].

For more details Spot blotch (wheat)

External links[edit]

References[edit]

  1. ^ a b Wiese, M.V. (1987). Compendium of wheat diseases. American Phytopathological Society. pp. 124 pp. Ascus