Meiosis and ascospore development in Cochliobolus heterostrophus

2008 ◽  
Vol 45 (4) ◽  
pp. 554-564 ◽  
Author(s):  
Namboori B. Raju
Keyword(s):  
Cochliobolus Heterostrophus ◽  
Ascospore Development

scholarly journals Intracellular Siderophores Are Essential for Ascomycete Sexual Development in Heterothallic Cochliobolus heterostrophus and Homothallic Gibberella zeae

2007 ◽  
Vol 6 (8) ◽  
pp. 1339-1353 ◽  
Author(s):  
Shinichi Oide ◽  
Stuart B. Krasnoff ◽  
Donna M. Gibson ◽  
B. Gillian Turgeon
Keyword(s):  
Sexual Development ◽  
Gibberella Zeae ◽  
Cochliobolus Heterostrophus ◽  
Fungal Development ◽  
Exogenous Application ◽  
Functional Conservation ◽  
Peptide Synthetase ◽  
Ascospore Development ◽  
Mutant Strains ◽  
Biochemical Analyses

ABSTRACT Connections between fungal development and secondary metabolism have been reported previously, but as yet, no comprehensive analysis of a family of secondary metabolites and their possible role in fungal development has been reported. In the present study, mutant strains of the heterothallic ascomycete Cochliobolus heterostrophus, each lacking one of 12 genes (NPS1 to NPS12) encoding a nonribosomal peptide synthetase (NRPS), were examined for a role in sexual development. One type of strain (Δnps2) was defective in ascus/ascospore development in homozygous Δnps2 crosses. Homozygous crosses of the remaining 11 Δnps strains showed wild-type (WT) fertility. Phylogenetic, expression, and biochemical analyses demonstrated that the NRPS encoded by NPS2 is responsible for the biosynthesis of ferricrocin, the intracellular siderophore of C. heterostrophus. Functional conservation of NPS2 in both heterothallic C. heterostrophus and the unrelated homothallic ascomycete Gibberella zeae was demonstrated. G. zeae Δnps2 strains are concomitantly defective in intracellular siderophore (ferricrocin) biosynthesis and sexual development. Exogenous application of iron partially restored fertility to C. heterostrophus and G. zeae Δnps2 strains, demonstrating that abnormal sexual development of Δnps2 strains is at least partly due to their iron deficiency. Exogenous application of the natural siderophore ferricrocin to C. heterostrophus and G. zeae Δnps2 strains restored WT fertility. NPS1, a G. zeae NPS gene that groups phylogenetically with NPS2, does not play a role in sexual development. Overall, these data demonstrate that iron and intracellular siderophores are essential for successful sexual development of the heterothallic ascomycete C. heterostrophus and the homothallic ascomycete G. zeae.

scholarly journals G-Protein β Subunit of Cochliobolus heterostrophus Involved in Virulence, Asexual and Sexual Reproductive Ability, and Morphogenesis

2004 ◽  
Vol 3 (6) ◽  
pp. 1653-1663 ◽  
Author(s):  
Sherif Ganem ◽  
Shun-Wen Lu ◽  
Bee-Na Lee ◽  
David Yu-Te Chou ◽  
Ruthi Hadar ◽  
...  
Keyword(s):  
Map Kinase ◽  
G Protein ◽  
Signal Transduction Pathway ◽  
Cochliobolus Heterostrophus ◽  
Wild Type ◽  
Heterotrimeric G Protein ◽  
Reproductive Ability ◽  
Pathway Gene ◽  
Mitogen Activated Protein ◽  
Nuclear Degradation

ABSTRACT Previous work established that mutations in mitogen-activated protein (MAP) kinase (CHK1) and heterotrimeric G-protein α (Gα) subunit (CGA1) genes affect the development of several stages of the life cycle of the maize pathogen Cochliobolus heterostrophus. The effects of mutating a third signal transduction pathway gene, CGB1, encoding the Gβ subunit, are reported here. CGB1 is the sole Gβ subunit-encoding gene in the genome of this organism. cgb1 mutants are nearly wild type in vegetative growth rate; however, Cgb1 is required for appressorium formation, female fertility, conidiation, regulation of hyphal pigmentation, and wild-type virulence on maize. Young hyphae of cgb1 mutants grow in a straight path, in contrast to those of the wild type, which grow in a wavy pattern. Some of the phenotypes conferred by mutations in CGA1 are found in cgb1 mutants, suggesting that Cgb1 functions in a heterotrimeric G protein; however, there are also differences. In contrast to the deletion of CGA1, the loss of CGB1 is not lethal for ascospores, evidence that there is a Gβ subunit-independent signaling role for Cga1 in mating. Furthermore, not all of the phenotypes conferred by mutations in the MAP kinase CHK1 gene are found in cgb1 mutants, implying that the Gβ heterodimer is not the only conduit for signals to the MAP kinase CHK1 module. The additional phenotypes of cgb1 mutants, including severe loss of virulence on maize and of the ability to produce conidia, are consistent with CGB1 being unique in the genome. Fluorescent DNA staining showed that there is often nuclear degradation in mature hyphae of cgb1 mutants, while comparable wild-type cells have intact nuclei. These data may be genetic evidence for a novel cell death-related function of the Gβ subunit in filamentous fungi.

Cochliobolus heterostrophus. [Distribution map].

2003 ◽  
Author(s):  
Keyword(s):  
South Carolina ◽  
New Caledonia ◽  
French Polynesia ◽  
American Samoa ◽  
Peninsular Malaysia ◽  
Marshall Islands ◽  
Cochliobolus Heterostrophus ◽  
Distribution Map ◽  
Mato Grosso ◽  
Brunei Darussalam

Abstract A new distribution map is provided for Cochliobolus heterostrophus (Drechsler) Drechsler Fungi: Ascomycota: Pleosporales Hosts: Maize (Zea mays), also a range of other crops, mostly legumes and cereals. Information is given on the geographical distribution in EUROPE, Bulgaria, Croatia, Cyprus, Denmark, France, Germany, Italy, Portugal, Romania, Russia, Southern, Russia, Spain, Switzerland, Ukraine, Yugoslavia (former), ASIA, Bangladesh, Bhutan, Brunei Darussalam, Cambodia, China, Anhui, Fujian, Gansu, Guangdong, Guangxi, Hebei, Heilongjiang, Henan, Hong Kong, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei, Menggu, Shaanxi, Shandong, Sichuan, Yunnan, Zhejiang, Christmas, Island, India, Andhra Pradesh, Assam, Bihar, Delhi, Haryana, Himachal Pradesh, Karnataka, Kerala, Lakshadweep, Madhya Pradesh, Meghalaya, Orissa, Punjab, Rajasthan, Uttar Pradesh, West Bengal, Indonesia, Irian Jaya, Java, Iran, Israel, Japan, Honshu, Kyushu, Shikoku, North Korea, Korea Republic, Laos, Malaysia, Peninsular Malaysia, Sabah, Sarawak, Myanmar, Nepal, Oman, Pakistan, Philippines, Sri Lanka, Taiwan, Thailand, Vietnam, AFRICA, Benin, Burkina Faso, Cameroon, Congo Democratic Republic, Cote d'Ivoire Egypt, Gabon, Ghana, Guinea, Kenya, Madagascar, Malawi, Mauritius, Mozambique, Niger, Nigeria, Reunion, Senegal, Sierra Leone, South Africa, Sudan, Swaziland, Tanzania, Togo, Zambia, Zimbabwe, NORTH AMERICA, Canada, New Brunswick, Nova Scotia, Ontario, Quebec, Mexico, USA, Arkansas, Delaware, District of Columbia, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, West Virginia, CENTRAL AMERICA & CARIBBEAN, Bahamas, Belize, Cuba, El Salvador, Guadeloupe, Guatemala, Jamaica, Nicaragua, Panama, Puerto Rico, Trinidad and Tobago, SOUTH AMERICA, Argentina, Bolivia, Brazil, Bahia, Mato, Grosso, do Sul, Parana, Colombia, Ecuador, French, Guiana, Guyana, Paraguay, Suriname, Venezuela, OCEANIA, American, Samoa, Australia, New South Wales, Northern Territory, Queensland, Fiji, French, Polynesia, Guam, Marshall, islands, New Caledonia, New Zealand, Niue, Papua New Guinea, Samoa, Solomon, Islands, Tonga, Vanuatu.

Cochliobolus heterostrophus. [Distribution map].

1981 ◽  
Author(s):  
Keyword(s):  
New Caledonia ◽  
New South ◽  
Solomon Islands ◽  
American Samoa ◽  
Cochliobolus Heterostrophus ◽  
Distribution Map ◽  
Irian Jaya ◽  
South Wales ◽  
Western Samoa ◽  
New Hebrides

Abstract A new distribution map is provided for Cochliobolus heterostrophus (Drechsl.) Drechsl. Hosts: Maize (Zea mays) and other Gramineae. Information is given on the geographical distribution in AFRICA, Dahomey, Egypt, Ghana, Guinea, Ivory Coast, Kenya, Malawi, Mauritius, Niger, Nigeria, Reunion, Senegal, Sierra Leone, South Africa, Sudan, Swaziland, Togo, Zaire, Zambia, Zimbabwe, ASIA, Bangladesh, Brunei, Burma, Cambodia, China (Honan, Manchuria, Nanking, Yunnan), Hong Kong, India (Delhi, Himalayas & S. India, West Bengal), (Bihar, Punjab), (Laccadive Ils), Indonesia (Irian Jaya), (Java), Israel, Japan, Korea, Laos, Malaysia, (W) (Sabah), (Sarawak), Nepal, Pakistan (SW), Philippines, Western Samoa, Thailand, Vietnam, AUSTRALASIA & OCEANIA, Australia (New South Wales, NT, Qd), Fiji, Hawaii, New Caledonia, New Hebrides, New Zealand, Papua New Guinea, Western Samoa, American Samoa, Solomon Islands, EUROPE, Cyprus, Denmark, France, Germany, Italy, Portugal, Romania, Spain, Switzerland, USSR (Caucasus), Yugoslavia, NORTH AMERICA, Canada (Ontario), (Quebec), Mexico, USA (Pa to Fla and Tex.), CENTRAL AMERICA & WEST INDIES, Bahamas, Belize, Cuba, Guatemala, Jamaica, Nicaragua, Panama, Salvador, Trinidad, SOUTH AMERICA, Argentina (Tucuman), Bolivia, Brazil (Bahia), Colombia, Eucador, French, Guiana, Guyana, Paraguay, Surinam, Venezuela.

Ascospore abortion in crosses of Cochliobolus heterostrophus heterozygous for the virulence locus Tox1

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Charlotte R. Bronson
Keyword(s):  
Key Words ◽  
Reciprocal Translocation ◽  
High Frequency ◽  
Chromosome Rearrangement ◽  
Cochliobolus Heterostrophus ◽  
Bipolaris Maydis ◽  
Field Isolates

Crosses heterozygous for the virulence locus Tox1 show a high frequency of nonrandom ascospore abortion, in addition to a high frequency of random abortion seen in homozygous crosses. In crosses among closely related laboratory strains, the frequency of asci with eight mature, viable spores dropped from 35–47% of asci with mature spores in crosses homozygous for Tox1 to 3–17% in heterozygous crosses. Segregation for alternate alleles of Tox1 was 2:2 in 98% of asci with four viable spores. Patterns of abortion in crosses involving field isolates were similar to the patterns in crosses among laboratory strains. No recombinants between Tox1 and the abortion-inducing factor were detected among 112 progeny of laboratory strains. The results suggest that race T (TOX1) and race O (tox1) strains of C. heterostrophus differ by a chromosome rearrangement, possibly a reciprocal translocation, with a breakpoint at or near Tox1.Key words: fertility, T-toxin, Cochliobolus heterostrophus, Helminthosporium maydis, Bipolaris maydis, Drechslera maydis, chromosome rearrangement, reciprocal translocation.

Cochliobolus heterostrophus. [Descriptions of Fungi and Bacteria].

1971 ◽  
Author(s):  
M. B. Ellis
Keyword(s):  
Zea Mays ◽  
Geographical Distribution ◽  
Leaf Sheath ◽  
Leaf Blight ◽  
Disease Spread ◽  
Cochliobolus Heterostrophus ◽  
Sorghum Vulgare ◽  
Main Host ◽  
The Tropics ◽  
Diffuse Lesion

Abstract A description is provided for Cochliobolus heterostrophus. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Generally on leaves of Zea mays, the main host, Euchlaena mexicana, Sorghum vulgare and many species of Gramineae (41: 40; 45, 3084; 48, 414; 50, 2257i). During an epidemic in USA caused by race T in 1970 no important hosts apart from Z. mays were noted (50, 2257b). DISEASE: Southern leaf blight of maize, forming very numerous lesions up to 2.5 cm long, mostly on the leaves. They are at first elliptical, then longitudinally elongate, becoming rectangular as restriction by the veins occurs; cinnamon-buff (sometimes with a purplish tint) with a reddish-brown margin and occasionally zonate, coalescing and becoming greyish with conidia. Symptoms caused by race T show a less well defined, somewhat diffuse lesion, with marginal chlorosis leading to leaf collapse, and all parts of the plant can be attacked. Perithecia have been recently reported in the field at the junction of leaf sheath and blade (50, 2257j). GEOGRAPHICAL DISTRIBUTION: Widespread in the tropics and subtropics (CMI Map 346, ed. 3, 1969) but not reported from Australia. Records not yet mapped are: Brunei, Guatemala, Hawaii, Israel, Laos, Mexico, Salvador and Venezuela. TRANSMISSION: Presumably air-dispersed but no detailed studies seem to have been reported. During the recent USA outbreak the disease spread from Florida to Maine in c. 6 months (50, 2257c). Spread by seed occurs (50, 3690, 3692; Crosier & Boothroyd, Phytopathology 61: 427, 747).

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