Nonrandom abortion of ascospores containing alternate alleles at the Tox-1 locus of the fungal plant pathogen Cochliobolus heterostrophus

1985 ◽  
Vol 27 (4) ◽  
pp. 450-456 ◽  
Author(s):  
M. Taga ◽  
C. R. Bronson ◽  
O. C. Yoder
Keyword(s):  
Plant Pathogen ◽  
Toxin Production ◽  
Low Fertility ◽  
Cochliobolus Heterostrophus ◽  
Bipolaris Maydis ◽  
High Frequencies ◽  
Field Isolates ◽  
Fungal Plant Pathogen ◽  
Inducing Factors ◽  
Aberrant Segregation

Crosses involving lab strains of C. heterostrophus that were previously selected for improved fertility yielded high frequencies of four-spored asci and only occasional asci with the full set of eight spores. Fertility in crosses between field isolates was low. Most asci contained two haploid spores; no asci had more than four spores. We investigated the distribution of aborted spores with respect to the three defined genetic loci Mat (mating type), Alb-1 (albinism), and Tox-1 (T-toxin production) and determined the frequency of mitotic twins in four-spored asci. Nonrandom spore abortion was evident from the observations that 80–100% of four-spored asci contained two sets of twins (9% expected for random abortion of mitotic products) and up to 95% of four-spored asci segregated 2:2 for alleles at the Tox-1 locus (67% expected for random abortion of meiotic products), suggesting preferential recovery of nonsister meiotic products. Segregation in crosses between field isolates tended to be skewed in favor of the tox-1a allele (specifies no toxin production). Alleles at Mat and Alb-1 segregated as expected for random abortion of meiotic products in both types of crosses. Low fertility and aberrant segregation among progeny segregating for ability to produce T toxin are likely due in part to abortion-inducing factors linked to Tox-1.Key words: fertility, ascomycetes, T toxin, Helminthosporium maydis, Bipolaris maydis.

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.

A reciprocal translocation and possible insertion(s) tightly associated with host-specific virulence in Cochliobolus heterostrophus

Genome ◽  
1996 ◽  
Vol 39 (3) ◽  
pp. 549-557 ◽  
Author(s):  
Hsin-Ru Chang ◽  
Charlotte R. Bronson
Keyword(s):  
Reciprocal Translocation ◽  
Chromosome Rearrangement ◽  
Natural Populations ◽  
Toxin Production ◽  
Cochliobolus Heterostrophus ◽  
Pulsed Field ◽  
Field Isolates ◽  
Pulsed Field Electrophoresis ◽  
Additional Chromosome ◽  
Tight Association

A reciprocal translocation and one or more apparent insertions are shown to be tightly associated with Tox1, a locus controlling T-toxin production and host-selective virulence in race T of the maize pathogen Cochliobolus heterostrophus. Chromosome arrangements were examined by separating chromosomal DNAs of a variety of Tox+ and Tox− strains by pulsed-field gel electrophoresis and hybridizing with probes known to detect RFLPs genetically linked to Tox1. The existence of the translocation was demonstrated by chromosome hybridization patterns; the existence of the putative insertion(s) was deduced from chromosome migration rates. Both differences in chromosome arrangement were detected between 8 Tox+ and 8 Tox− near-isogenic laboratory strains, suggesting that the differences are tightly linked to Tox1. The reciprocal translocation was also detected between all 7 Tox+ and 8 Tox− field isolates examined, suggesting that the translocation is common in natural populations. The field isolates may also differ by the insertion(s); however, numerous additional chromosome size polymorphisms in the field isolates prevented a firm conclusion. The tight association of the translocation and insertion(s) with T-toxin production suggests that chromosome rearrangements may have been involved in the evolution of race T and Tox1. These genomic differences may be causally related to the previously reported reduced fitness of race T relative to race O on N-cytoplasm maize. Key words : chromosome rearrangement, southern corn leaf blight, pulsed-field electrophoresis, T-toxin, evolution.

scholarly journals SPORE KILLER POLYMORPHISM IN FUSARIUM MONILIFORME

Genetics ◽  
1982 ◽  
Vol 102 (1) ◽  
pp. 19-24
Author(s):  
Sophia Kathariou ◽  
Philip T Spieth
Keyword(s):  
Central America ◽  
Plant Pathogen ◽  
Fusarium Moniliforme ◽  
Natural Populations ◽  
Neurospora Intermedia ◽  
Fungal Plant Pathogen ◽  
Spore Killer

ABSTRACT A Spore killer trait, which exhibits genetic and cytological properties analogous to those previously found in Neurospora, exists in natural populations of the fungal plant pathogen Fusarium moniliforme. The genogeography of the polymorphism in F. moniliforme differs from the situation in Neurospora intermedia. It is more akin to the situation in N. sitophila, although more extreme with respect to the prevalence of killer alleles: more than 80% of tested isolates of F. moniliforme carry the killer allele. Nevertheless, sensitive alleles are widely distributed and have been found in California, Italy, Greece and Central America.

scholarly journals Transcriptional response to host chemical cues underpins the expansion of host range in a fungal plant pathogen lineage

2021 ◽  
Author(s):  
Stefan Kusch ◽  
Justine Larrouy ◽  
Heba M. M. Ibrahim ◽  
Shantala Mounichetty ◽  
Noémie Gasset ◽  
...  
Keyword(s):  
Host Range ◽  
Plant Pathogen ◽  
Chemical Cues ◽  
Transcriptional Response ◽  
Fungal Plant Pathogen

scholarly journals Absence of isolation by distance patterns at the regional scale in the fungal plant pathogen Leptosphaeria maculans

2011 ◽  
Vol 115 (7) ◽  
pp. 649-659 ◽  
Author(s):  
Renaud Travadon ◽  
Ivan Sache ◽  
Cyril Dutech ◽  
Anna Stachowiak ◽  
Bruno Marquer ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Isolation By Distance ◽  
Regional Scale ◽  
Leptosphaeria Maculans ◽  
Fungal Plant Pathogen

scholarly journals Development of a Highly Sensitive FcMito qPCR Assay for the Quantification of the Toxigenic Fungal Plant Pathogen Fusarium culmorum

Toxins ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 211 ◽  
Author(s):  
Katarzyna Bilska ◽  
Tomasz Kulik ◽  
Anna Ostrowska-Kołodziejczak ◽  
Maciej Buśko ◽  
Matias Pasquali ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Fusarium Culmorum ◽  
Qpcr Assay ◽  
Highly Sensitive ◽  
Fungal Plant Pathogen
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