Cochliobolus sativus
Encyclopedia
The fungus
Fungus
A fungus is a member of a large 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, Fungi, which is separate from plants, animals, and bacteria...

 Cochliobolus sativus is the teleomorph (sexual stage) of Bipolaris sorokiniana (anamorph) which is the causal agent of a wide variety of cereal
Cereal
Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...

 diseases. The pathogen can infect and cause disease on the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

 (where it is known as common root rot
Common root rot (wheat)
Common root rot is a disease of wheat caused by one or more fungi. Cochliobolus sativus , Fusarium culmorum and F. graminearum are the most common pathogens responsible for common root rot.-Symptoms:...

), leaf and stem, and head tissue. C.sativus is extremely rare in nature and thus it is the asexual
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...

 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 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.

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
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...

 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.

Host species

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

Geographical distribution

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

Main diseases

Common root rot (barley)
Common root rot (barley)
Common root rot is a fungal disease of barley caused by Cochliobolus sativus, Fusarium culmorum and F. graminearum.- Symptoms :Initial symptoms appear as small brown spots on the crown roots, the lower sheath, and the subcrown internode...

; Common root rot (wheat)
Common root rot (wheat)
Common root rot is a disease of wheat caused by one or more fungi. Cochliobolus sativus , Fusarium culmorum and F. graminearum are the most common pathogens responsible for common root rot.-Symptoms:...

; spot blotch (barley)
Spot blotch (barley)
Spot blotch is a disease of barley caused by Cochliobolus sativus. The disease is found everywhere that barley is grown, but only causes significant yield losses in warm, humid climates.- Symptoms :...

; Spot blotch (wheat)
Spot blotch (wheat)
Spot blotch is a leaf disease of wheat caused by Cochliobolus sativus. Cochliobolus sativus also infects other plant parts and in conjunction with other pathogens causes common root rot and black point.-Introduction:...


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.

For more details Spot blotch (wheat)
Spot blotch (wheat)
Spot blotch is a leaf disease of wheat caused by Cochliobolus sativus. Cochliobolus sativus also infects other plant parts and in conjunction with other pathogens causes common root rot and black point.-Introduction:...


External links


Research articles

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