Cochliobolus sativus

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Cochliobolus sativus
Cochliobolus sativus - Lindsey.jpg
Symptoms on a wheat leaf
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Dothideomycetes
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 californicumMackie & G.E. Paxton (1923)
Helminthosporium sativumPammel, C.M. King & Bakke (1910)
Helminthosporium sorokinianumSacc. (1890)
Ophiobolus sativusS. Ito & Kurib. (1929)

Contents

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 roots (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

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 septum. 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

Agropyron cristatum 1, Allium sp. 1, Alopecurus pratensis 1, Aneurolepidium chinense 1, Avena sativa 1

Bromus inermis 1, B. marginatus1, B. willdenowii1

Calluna vulgaris 1, Chloris gayana 1, Cicer arietinum 1, Clinelymus dahuricus 1, C. sibiricus1, Cynodon dactylon 1, C. transvaalensis1

Dactylis glomerata 1

Echinochloa crus-galli 1, Elymus junceus 1

Festuca sp. 1

Guzmania sp. 1

Hordeum brevisubulatum 1, H. distichon1, H. sativum var. hexastichon1, H. vulgare 1, H. vulgare var. hexastichon1

Lablab purpureus 1, Linum usitatissimum 1, Lolium multiflorum 1

Pennisetum typhoides 1

Roegneria semicostata 1

Saccharum sp. 1, Secale cereale 1, Setaria italica 1, Sorghum sp. 1

Taraxacum kok-saghyz 1, Trisetum aestivum 1, Triticum aestivum 1, T. secale1, T. turgidum subsp. durum, T. vulgare1

Zea mays 1

Notes

1. USDA ARS Fungal Database

Geographical distribution

Cochliobolus sativus has a world-wide distribution.

Geographical distribution
AfricaKenya,1 Malawi,1 Sudan,1 South Africa, 1 Tanzania, 1 Zimbabwe1
AustralasiaAustralia,1 China, 1 Korea, 1 India, 1 Indonesia, 1 New Zealand,1 Papua New Guinea,1 Taiwan, 1 Thailand1
Central AmericaCuba, 1 Mexico, 1 Nicaragua1
EuropeAustria, 1 Belgium, 1 Czechoslovakia, 1 Denmark, 1 Finland, 2 Germany, 1 Greece, 1 Hungary, 1 Italy, 1 Poland, 1 Scotland, 1 United Kingdom, 1 USSR
North AmericaCanada (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 AmericaArgentina, 1 Brazil1

Notes

1. USDA ARS Fungal Database 2.

Main diseases

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

Spot blotch of wheat

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 ].

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References

  1. 1 2 Wiese, M.V. (1987). Compendium of wheat diseases. American Phytopathological Society. pp. 124 pp.Ascus