Genetic Analysis and Mapping of Avirulence Genes in Magnaporthe grisea

2020 ◽  
pp. 295-315
Author(s):  
Mark L. Farman ◽  
Sally Ann Leong
Keyword(s):  
Genetic Analysis ◽  
Magnaporthe Grisea ◽  
Avirulence Genes

scholarly journals Induced Rice Resistance to Blast Varies as a Function of Magnaporthe grisea Avirulence Genes

Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1144-1149 ◽  
Author(s):  
N. Yasuda ◽  
M. T. Noguchi ◽  
Y. Fujita
Keyword(s):  
Genetic Analysis ◽  
Resistance Genes ◽  
Magnaporthe Grisea ◽  
Specific Resistance ◽  
Blast Disease ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
Leaf Blast ◽  
Incompatibility Reactions ◽  
Avirulent Isolate

Incompatibility reactions between rice and the blast fungus Magnaporthe grisea produce various degrees of lesions, from large brown flecks to small, nearly invisible lesions. We previously identified four avirulence genes (AvrPia, AvrPii, AvrPit, and Avr-Hattan3) in M. grisea isolates by genetic analysis of progeny from crosses between isolates with differing pathogenicity. Using progeny known to contain a specific avirulence gene, we demonstrated that the type of resistance lesion produced in rice by an avirulent isolate and the degree of leaf blast suppression by preinoculation with that isolate were determined by the combination of avirulence and resistance genes in the isolate and the cultivar. The degree of leaf blast suppression by preinoculation with an avirulent isolate increased with larger resistance lesions. When two genes were involved in an isolate's avirulence, lesions appeared that resembled those expected for the gene that produced the smaller lesion. The degree of leaf blast suppression by the isolate with two avirulence genes was comparable with that induced by the isolate with the avirulence gene that produced the smaller effect. The ability of specific resistance gene combinations that effectively suppress blast disease is discussed for each avirulence gene.

scholarly journals Genetic Analysis of Avirulence/Virulence of an Isolate of Magnaporthe grisea from a Rice Field in Texas

1997 ◽  
Vol 87 (1) ◽  
pp. 71-76 ◽  
Author(s):  
C. T. Chao ◽  
A. H. Ellingboe
Keyword(s):  
Genetic Analysis ◽  
Magnaporthe Grisea ◽  
Rice Field ◽  
Laboratory Strain ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
Three Generations ◽  
Segregation Ratios

An isolate of Magnaporthe grisea, Tm4, from a rice field in Texas was crossed with a fertile laboratory strain, 70-6. The progenies showed segregation of avirulence/virulence on rice cvs. Newbonnet, Lemont, Lebonnet, Leah, and Katy. The avirulent/virulent segregation ratios were 29:6 on Newbonnet, Lemont, and Lebonnet; 28:7 on Leah; and 33:2 on Katy. There was cosegregation on the first three cultivars. Several avirulent progenies were backcrossed to virulent parent 70-6. Three generations of backcrossing avirulent progenies to 70-6 led to segregation ratios that suggested certain strains had only one avirulence gene. Strains avirulent only on cv. Katy or only on cvs. Newbonnet, Lemont, and Lebonnet were test crossed with virulent siblings. Strains that gave progeny ratios approximating 1 avirulent:1 virulent when crossed with virulent siblings were selected for further test crossing. Intercrosses between strains with possible single avirulence genes were made to determine whether these strains had the same or different avirulence genes. Many lines still segregated two genes for avirulence after three generations of backcrossing. This is based on the recovery of virulent progenies from crossing two avirulent siblings.

scholarly journals Applying comparative genomics to plant disease epidemiology

2004 ◽  
Vol 85 (1) ◽  
pp. 45-48 ◽  
Author(s):  
Linda M. Kohn
Keyword(s):  
Magnaporthe Grisea ◽  
Sequence Data ◽  
Population Level ◽  
Avirulence Genes ◽  
Genome Database ◽  
Disease Epidemiology ◽  
Dna Sequence Data ◽  
Specific Pathogen ◽  
Pathogen Populations ◽  
Genomic Regions

Astract Phylogenetic or genealogical interpretation of DNA sequence data from multiple genomic regions has become the gold standard for species delimitation and population genetics. Precise species concepts can inform quarantine decisions but are likely to reflect evolutionary events too far in the past to impact disease management. On the other hand, multilocus approaches at the population level can identify patterns of endemism or migration directly associated with episodes of disease, including host shifts and associated changes in determinants of pathogenicity and avirulence. We used the genome database of Magnaporthe grisea to frame a comparative, multilocus genomics approach from which we demonstrate a single origin for rice infecting genotypes with concomitant loss of sex in pandemic clonal lineages, and patterns of gain and loss of avirulence genes. In the Sclerotinia sclerotiorum pathosystem, we identified significant associations of multilocus haplotypes with specific pathogen populations in North America. Following the introduction of a new crop, endemic pathogen genotypes and newly evolved migrant genotypes caused novel, early-season symptoms.

Molecular mapping of two cultivar-specific avirulence genes in the rice blast fungus Magnaporthe grisea

2006 ◽  
Vol 277 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Q. H. Chen ◽  
Y. C. Wang ◽  
A. N. Li ◽  
Z. G. Zhang ◽  
X. B. Zheng
Keyword(s):  
Rice Blast ◽  
Magnaporthe Grisea ◽  
Molecular Mapping ◽  
Rice Blast Fungus ◽  
Avirulence Genes ◽  
Blast Fungus

Relationship between Avirulence Genes of the Same Family in Rice Blast Fungus Magnaporthe grisea

2002 ◽  
Vol 68 (4) ◽  
pp. 300-306 ◽  
Author(s):  
Chao-Xi LUO ◽  
Hiromi HANAMURA ◽  
Hiroyo SEZAKI ◽  
Motoaki KUSABA ◽  
Hiroshi YAEGASHI
Keyword(s):  
Rice Blast ◽  
Magnaporthe Grisea ◽  
Rice Blast Fungus ◽  
Avirulence Genes ◽  
Blast Fungus

scholarly journals Mapping of Avirulence Genes in the Rice Blast Fungus, Magnaporthe grisea, with RFLP and RAPD Markers

2000 ◽  
Vol 13 (2) ◽  
pp. 217-227 ◽  
Author(s):  
Waly Dioh ◽  
Didier Tharreau ◽  
Jean Loup Notteghem ◽  
Marc Orbach ◽  
Marc-Henri Lebrun
Keyword(s):  
Genetic Map ◽  
Rice Blast ◽  
Rapd Markers ◽  
Magnaporthe Grisea ◽  
Rice Blast Fungus ◽  
Single Copy ◽  
Avirulence Gene ◽  
Rflp Markers ◽  
Avirulence Genes ◽  
Blast Fungus

Three genetically independent avirulence genes, AVR1-Irat7, AVR1-MedNoï, and AVR1-Ku86, were identified in a cross involving isolates Guy11 and 2/0/3 of the rice blast fungus, Magnaporthe grisea. Using 76 random progeny, we constructed a partial genetic map with restriction fragment length polymorphism (RFLP) markers revealed by probes such as the repeated sequences MGL/MGR583 and Pot3/MGR586, cosmids from the M. grisea genetic map, and a telomere sequence oligonucleotide. Avirulence genes AVR1-MedNoï and AVR1-Ku86 were closely linked to te-lomere RFLPs such as marker TelG (6 cM from AVR1-MedNoï) and TelF (4.5 cM from AVR1-Ku86). Avirulence gene AVR1-Irat7 was linked to a cosmid RFLP located on chromosome 1 and mapped at 20 cM from the avirulence gene AVR1-CO39. Using bulked segregant analysis, we identified 11 random amplified polymorphic DNA (RAPD) markers closely linked (0 to 10 cM) to the avirulence genes segregating in this cross. Most of these RAPD markers corresponded to junction fragments between known or new transposons and a single-copy sequence. Such junctions or the whole sequences of single-copy RAPD markers were frequently absent in one parental isolate. Single-copy sequences from RAPD markers tightly linked to avirulence genes will be used for positional cloning.

Genetic analysis of the avirulence of wheatgrass powdery mildew fungus on common wheat

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 913-917 ◽  
Author(s):  
Y. Tosa
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Genetic Analysis ◽  
Common Wheat ◽  
Erysiphe Graminis ◽  
Wheat Cultivars ◽  
Avirulence Genes ◽  
Powdery Mildew Fungus ◽  
Major Genes ◽  
Formae Speciales

F1 hybrid cultures between Erysiphe graminis f.sp. agropyri (wheatgrass mildew fungus) and E. graminis f.sp. tritici (wheat mildew fungus) were produced by using a common host of the two formae spéciales. When three common wheat cultivars, Triticum aestivum cv. Norin 4, T. aestivum cv. Norin 10, and T. compactum cv. No. 44, were inoculated with a population of F1 cultures, avirulent and virulent cultures segregated in a 3:1 ratio. This indicated that two major genes are involved in the avirulence of E. graminis f.sp. agropyri, Ak-1, on each of the three cultivars. Further analyses revealed that the three pairs of avirulence genes have one gene in common. On T. aestivum cv. Shin-chunaga, T. aestivum cv. Norin 26, and a strain of T. macha, the F1 population segregated in the same pattern as on T. aestivum cv. Norin 4, indicating that the same pair of avirulence genes is operating on these four cultivars. On T. aestivum cv. Red Egyptian the distribution of F1 phenotypes was continuous, suggesting that no major genes are involved in the avirulence of Ak-1 on this cultivar.Key words: powdery mildew, Erysiphe graminis, avirulence, wheat, wheatgrass.

scholarly journals Magnaporthe grisea genes for pathogenicity and virulence identified through a series of backcrosses.

Genetics ◽  
1991 ◽  
Vol 127 (1) ◽  
pp. 87-101 ◽  
Author(s):  
B Valent ◽  
L Farrall ◽  
F G Chumley
Keyword(s):  
Dna Sequences ◽  
Magnaporthe Grisea ◽  
Pathogenic Fungus ◽  
Field Isolate ◽  
Recurrent Parent ◽  
High Fertility ◽  
Rice Cultivars ◽  
Avirulence Genes ◽  
Chromosomal Dna ◽  
Fertile Female

Abstract We have identified genes for pathogenicity toward rice (Oryza sativa) and genes for virulence toward specific rice cultivars in the plant pathogenic fungus Magnaporthe grisea. A genetic cross was conducted between the weeping lovegrass (Eragrostis curvula) pathogen 4091-5-8, a highly fertile, hermaphroditic laboratory strain, and the rice pathogen O-135, a poorly fertile, female-sterile field isolate that infects weeping lovegrass as well as rice. A six-generation backcrossing scheme was then undertaken with the rice pathogen as the recurrent parent. One goal of these crosses was to generate rice pathogenic progeny with the high fertility characteristic of strain 4091-5-8, which would permit rigorous genetic analysis of rice pathogens. Therefore, progeny strains to be used as parents for backcross generations were chosen only on the basis of fertility. The ratios of pathogenic to nonpathogenic (and virulent to avirulent) progeny through the backcross generations suggested that the starting parent strains differ in two types of genes that control the ability to infect rice. First, they differ by polygenic factors that determine the extent of lesion development achieved by those progeny that infect rice. These genes do not appear to play a role in infection of weeping lovegrass because both parents and all progeny infect weeping lovegrass. Second, the parents differ by simple Mendelian determinants, "avirulence genes," that govern virulence toward specific rice cultivars in all-or-none fashion. Several crosses confirm the segregation of three unlinked avirulence genes, Avr 1-CO39, Avr 1-M201 and Avr1-YAMO, alleles of which determine avirulence on rice cultivars CO39, M201, and Yashiro-mochi, respectively. Interestingly, avirulence alleles of Avr1-CO39, Avr1-M201 and Avr1-YAMO were inherited from the parent strain 4091-5-8, which is a nonpathogen of rice. Middle repetitive DNA sequences ("MGR sequences"), present in approximately 40-50 copies in the genome of the rice pathogen parent, and in very low copy number in the genome of the nonpathogen of rice, were used as physical markers to monitor restoration of the rice pathogen genetic background during introgression of fertility. The introgression of highest levels of fertility into the most successful rice pathogen progeny was incomplete by the sixth generation, perhaps a consequence of genetic linkage between genes for fertility and genes for rice pathogenicity. One chromosomal DNA segment with MGR sequence homology appeared to be linked to the gene Avr1-CO39. Finally, many of the crosses described in this paper exhibited a characteristic common to many crosses involving M. grisea rice pathogen field isolates.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Complementation of the Magnaporthe grisea ΔcpkA Mutation by the Blumeria graminis PKA-c Gene: Functional Genetic Analysis of an Obligate Plant Pathogen

2001 ◽  
Vol 14 (12) ◽  
pp. 1368-1375 ◽  
Author(s):  
Lene Bindslev ◽  
Michael J. Kershaw ◽  
Nicholas J. Talbot ◽  
Richard P. Oliver
Keyword(s):  
Signal Transduction ◽  
Genetic Analysis ◽  
Magnaporthe Grisea ◽  
Functional Characterization ◽  
Pathogenic Fungi ◽  
Blumeria Graminis ◽  
Powdery Mildew Fungus ◽  
Reading Frame ◽  
Related Development ◽  
Obligate Pathogen

Obligate plant-pathogenic fungi have proved extremely difficult to characterize with molecular genetics because they cannot be cultured away from host plants and only can be manipulated experimentally in limited circumstances. Previously, in order to characterize signal transduction processes during infection-related development of the powdery mildew fungus Blumeria graminis (syn. Erysiphe graminis) f. sp. hordei, we described a gene similar to the catalytic subunit of cyclic AMP-dependent protein kinase A (here renamed Bka1). Functional characterization of this gene has been achieved by expression in a ΔcpkA mutant of the nonobligate pathogen Magnaporthe grisea. This nonpathogenic M. grisea ΔcpkA mutant displays delayed and incomplete appressorium development, suggesting a role for PKA-c in the signal transduction processes that control the maturation of infection cells. Transformation of the ΔcpkA mutant with the mildew Bka1 open reading frame, controlled by the M. grisea MPG1 promoter, restored pathogenicity and appressorium maturation kinetics. The results provide, to our knowledge, the first functional genetic analysis of pathogenicity in an obligate pathogen and highlight the remarkable conservation of signaling components regulating infection-related development in pathogenic fungi.

Sign in / Sign up

Export Citation Format

Share Document