scholarly journals Analysis of Host Species Specificity of Magnaporthe grisea Toward Foxtail Millet Using a Genetic Cross Between Isolates from Wheat and Foxtail Millet

2003 ◽  
Vol 93 (1) ◽  
pp. 42-45 ◽  
Author(s):  
J. Murakami ◽  
R. Tomita ◽  
T. Kataoka ◽  
H. Nakayashiki ◽  
Y. Tosa ◽  
...  
Keyword(s):  
Host Species ◽  
Magnaporthe Grisea ◽  
Foxtail Millet ◽  
Species Specificity ◽  
The Other ◽  
Single Locus ◽  
Gene Interactions ◽  
Genetic Cross ◽  
Genetic Mechanisms ◽  
Cultivar Specificity

Host species specificity of Magnaporthe grisea toward foxtail millet was analyzed using F1 cultures derived from a cross between a Triticum isolate (pathogenic on wheat) and a Setaria isolate (pathogenic on foxtail millet). On foxtail millet cvs. Beni-awa and Oke-awa, avirulent and virulent cultures segregated in a 1:1 ratio, suggesting that a single locus is involved in the specificity. This locus was designated as Pfm1. On cv. Ki-awa, two loci were involved and one of them was Pfm1. The other locus was designated as Pfm2. Interestingly, Pfm1 was not involved in the pathogenic specificity on cv. Kariwano-zairai. These results suggest that there is no “master gene” that determines the pathogenic specificity on all foxtail millet cultivars and that the species specificity of M. grisea toward foxtail millet is governed by cultivar-dependent genetic mechanisms that are similar to gene-for-gene interactions controlling race-cultivar specificity.

scholarly journals Analysis of Host Species Specificity of Magnaporthe grisea Toward Wheat Using a Genetic Cross Between Isolates from Wheat and Foxtail Millet

2000 ◽  
Vol 90 (10) ◽  
pp. 1060-1067 ◽  
Author(s):  
J. Murakami ◽  
Y. Tosa ◽  
T. Kataoka ◽  
R. Tomita ◽  
J. Kawasaki ◽  
...  
Keyword(s):  
Host Species ◽  
Magnaporthe Grisea ◽  
Foxtail Millet ◽  
Hypersensitive Reaction ◽  
Species Specificity ◽  
Genetic Cross ◽  
Genetic Mechanisms ◽  
Papilla Formation ◽  
Wheat Leaves

A genetic cross was performed between a Setaria isolate (pathogenic on foxtail millet) and a Triticum isolate (pathogenic on wheat) of Magnaporthe grisea to elucidate genetic mechanisms of its specific parasitism toward wheat. A total of 80 F1 progenies were obtained from 10 mature asci containing 8 ascospores. Lesions on wheat leaves produced by the F1 progenies were classified into four types, which segregated in a 1:1:1:1 ratio. This result suggested that the pathogenicity of the F1 population on wheat was controlled by two genes located at different loci. This idea was supported by backcross analyses. We designated these loci as Pwt1 and Pwt2. Cytological analyses revealed that Pwt1 and Pwt2 were mainly associated with the hypersensitive reaction and papilla formation, respectively.

scholarly journals A Gene-for-Gene Relationship Underlying the Species-Specific Parasitism of Avena/Triticum Isolates of Magnaporthe grisea on Wheat Cultivars

2002 ◽  
Vol 92 (11) ◽  
pp. 1182-1188 ◽  
Author(s):  
N. Takabayashi ◽  
Y. Tosa ◽  
H. S. Oh ◽  
S. Mayama
Keyword(s):  
Resistance Gene ◽  
Temperature Sensitivity ◽  
Chinese Spring ◽  
Magnaporthe Grisea ◽  
Gene Interactions ◽  
Wheat Cultivars ◽  
Genetic Mechanisms ◽  
Species Specific ◽  
Cultivar Specificity ◽  
Gene For Gene

To elucidate genetic mechanisms of the species-specific parasitism of Magnaporthe grisea, a Triticum isolate (pathogenic on wheat) was crossed with an Avena isolate (pathogenic on oat), and resulting F1 progeny were subjected to segregation analyses on wheat cvs. Norin 4 and Chinese Spring. We found two fungal loci, Pwt3 and Pwt4, which are involved in the specific parasitism on wheat. Pwt3 operated on both cultivars while Pwt4 operated only on ‘Norin 4’. Using the cultivar specificity of Pwt4, its corresponding resistance gene was successfully identified in ‘Norin 4’ and designated as Rmg1 (Rwt4). The presence of the corresponding resistance gene indicated that Pwt4 is an avirulence locus. Pwt3 was assumed to be an avirulence locus because of its temperature sensitivity. We suggest that gene-for-gene interactions underlie the species-specific parasitism of M. grisea.

Genetic analysis and molecular mapping of the avirulence gene PRE1, a gene for host-species specificity in the blast fungus Magnaporthe grisea

Genome ◽  
2006 ◽  
Vol 49 (8) ◽  
pp. 873-881 ◽  
Author(s):  
Q H Chen ◽  
Y C Wang ◽  
X B Zheng
Keyword(s):  
Genetic Analysis ◽  
Ssr Markers ◽  
Host Species ◽  
Magnaporthe Grisea ◽  
Species Specificity ◽  
Avirulence Gene ◽  
Chromosome 3 ◽  
Genetic Linkage Analysis ◽  
Genetic Mechanisms ◽  
Species Specific

We analyzed host-species specificity of Magnaporthe grisea on rice using 110 F1 progeny derived from a cross between the Oryza isolate CH87 (pathogenic to rice) and the Digitaria isolate 6023 (pathogenic to crabgrass). To elucidate the genetic mechanisms controlling species specificity in M. grisea, we performed a genetic analysis of species-specific avirulence on this rice population. Avirulent and virulent progeny segregated in a 1:1 ratio on the 2 rice cultivars 'Lijiangxintuanheigu' (LTH) and 'Shin2', suggesting that a single locus, designated PRE1, was involved in the specificity. In a combination between 'Kusabue' and 'Tsuyuake', the segregation of the 4 possible phenotypes of F1 progeny was significantly different from the expected 3:1:3:1 and instead fit a ratio of 2:0:1:1. This indicated that 2 loci, PRE1 and AVR2, were involved in specific parasitism on rice. These results suggest that the species specificity of M. grisea on rice is governed by species-dependent genetic mechanisms that are similar to the gene-for-gene interactions controlling cultivar specificity. Pathogenicity tests with various plant species revealed that the Digitaria isolate 6023 was exclusively parasitic on crabgrass. Genetic linkage analysis showed that PRE1 was mapped on chromosome 3 with respect to RAPD and SSR markers. RAPD marker S361 was linked to the avirulence gene at a distance of ~6.4 cM. Two SSR markers, m677–678 and m77–78, were linked to the PRE1 gene on M. grisea chromosome 3 at distances of 5.9 and 7.1 cM, respectively. Our results will facilitate positional cloning and functional studies of this gene.Key words: genetic analysis, graminaceous plants, Magnaporthe grisea, species-specific avirulence gene.

scholarly journals Genetic Analysis of Host Species Specificity of Magnaporthe oryzae Isolates from Rice and Wheat

2006 ◽  
Vol 96 (5) ◽  
pp. 480-484 ◽  
Author(s):  
Y. Tosa ◽  
H. Tamba ◽  
K. Tanaka ◽  
S. Mayama
Keyword(s):  
Genetic Analysis ◽  
Magnaporthe Oryzae ◽  
Host Species ◽  
Hypersensitive Reaction ◽  
Species Specificity ◽  
The Other ◽  
Papilla Formation ◽  
Allelism Tests

A Triticum isolate (pathogenic on wheat) of Magnaporthe oryzae was crossed with an Oryza isolate (pathogenic on rice) to elucidate mechanisms of their parasitic specificity on wheat. When the pathogenicity of their F 1 cultures (hybrids between a Triticum isolate and an Oryza isolate) was tested on wheat, avirulent and virulent cultures segregated in a 7:1 ratio. This result suggests that three loci are involved in avirulence of the Oryza isolate on wheat. One of the three loci conditioned papilla formation, whereas the others conditioned the hypersensitive reaction. Allelism tests revealed that the locus conditioning papilla formation is Pwt2 while one of the two loci conditioning the hypersensitive reaction is Pwt1. The other locus conditioning the hypersensitive reaction was different from any other known loci and, therefore, was designated as Pwt5.

scholarly journals Higher mortality of the less suitable brown trout host compared to the principal Atlantic salmon host when infested with freshwater pearl mussel (Margaritifera margaritifera) glochidia

2021 ◽  
Author(s):  
Janhavi Marwaha ◽  
Per Johan Jakobsen ◽  
Sten Karlsson ◽  
Bjørn Mejdell Larsen ◽  
Sebastian Wacker
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Host Species ◽  
Salmo Trutta ◽  
The Other ◽  
Margaritifera Margaritifera ◽  
Pearl Mussel ◽  
Suitable Host ◽  
Freshwater Pearl Mussel ◽  
Host Interaction

AbstractThe freshwater pearl mussel (Margaritifera margaritifera) is a highly host-specific parasite, with an obligate parasitic stage on salmonid fish. Atlantic salmon (Salmo salar) and brown trout (Salmo trutta f. trutta and Salmo trutta f. fario) are the only hosts in their European distribution. Some M. margaritifera populations exclusively infest either Atlantic salmon or brown trout, while others infest both hosts with one salmonid species typically being the principal host and the other a less suitable host. Glochidial abundance, prevalence and growth are often used as parameters to measure host suitability, with the most suitable host species displaying the highest parameters. However, it is not known if the degree of host specialisation will negatively influence host fitness (virulence) among different host species. In this study we examined the hypothesis that glochidial infestation would result in differential virulence in two salmonid host species and that lower virulence would be observed on the most suitable host. Atlantic salmon and brown trout were infested with glochidia from two M. margaritifera populations that use Atlantic salmon as their principal host, and the difference in host mortality among infested and control (sham infested) fish was examined. Higher mortality was observed in infested brown trout (the less suitable host) groups, compared to the other test groups. Genetic assignment was used to identify offspring from individual mother mussels. We found that glochidia from individual mothers can infest both the salmonid hosts; however, some mothers displayed a bias towards either salmon or trout. We believe that the differences in host-dependent virulence and the host bias displayed by individual mothers were a result of genotype × genotype interactions between the glochidia and their hosts, indicating that there is an underlying genetic component for this parasite-host interaction.

scholarly journals Identification of a Novel Locus Rmo2 Conditioning Resistance in Barley to Host-Specific Subgroups of Magnaporthe oryzae

2012 ◽  
Vol 102 (7) ◽  
pp. 674-682 ◽  
Author(s):  
Nguyen Thi Thanh Nga ◽  
Yoshihiro Inoue ◽  
Izumi Chuma ◽  
Gang-Su Hyon ◽  
Kazuma Okada ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Molecular Mapping ◽  
The Other ◽  
Avirulence Gene ◽  
Barley Cultivar ◽  
Avirulence Genes ◽  
Genetic Crosses ◽  
Barley Cultivars ◽  
Genetic Mechanisms ◽  
Common Parent

Barley cultivars show various patterns of resistance against isolates of Magnaporthe oryzae and M. grisea. Genetic mechanisms of the resistance of five representative barley cultivars were examined using a highly susceptible barley cultivar, ‘Nigrate’, as a common parent of genetic crosses. The resistance of the five cultivars against Setaria, Oryza, Eleusine, and Triticum isolates of M. oryzae was all attributed to a single locus, designated as Rmo2. Nevertheless, the Rmo2 locus in each cultivar was effective against a different range of isolates. Genetic analyses of pathogenicity suggested that each cultivar carries an allele at the Rmo2 locus that recognizes a different range of avirulence genes. One allele, Rmo2.a, corresponded to PWT1, which conditioned the avirulence of Setaria and Oryza isolates on wheat, in a gene-for-gene manner. The other alleles, Rmo2.b, Rmo2.c, and Rmo2.d, corresponded to more than one avirulence gene. On the other hand, the resistance of those cultivars to another species, M. grisea, was conditioned by another locus, designated as Rmo3. These results suggest that Rmo2 is effective against a broad range of blast isolates but is specific to M. oryzae. Molecular mapping revealed that Rmo2 is located on the 7H chromosome.

scholarly journals The barley immune receptor Mla recognizes multiple pathogens and contributes to host range dynamics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jan Bettgenhaeuser ◽  
Inmaculada Hernández-Pinzón ◽  
Andrew M. Dawson ◽  
Matthew Gardiner ◽  
Phon Green ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Stripe Rust ◽  
Resistance Genes ◽  
Host Species ◽  
Plant Pathogens ◽  
Puccinia Striiformis ◽  
Species Specificity ◽  
Wheat Stripe Rust ◽  
Barley Powdery Mildew ◽  
Barley Stripe Rust

AbstractCrop losses caused by plant pathogens are a primary threat to stable food production. Stripe rust (Puccinia striiformis) is a fungal pathogen of cereal crops that causes significant, persistent yield loss. Stripe rust exhibits host species specificity, with lineages that have adapted to infect wheat and barley. While wheat stripe rust and barley stripe rust are commonly restricted to their corresponding hosts, the genes underlying this host specificity remain unknown. Here, we show that three resistance genes, Rps6, Rps7, and Rps8, contribute to immunity in barley to wheat stripe rust. Rps7 cosegregates with barley powdery mildew resistance at the Mla locus. Using transgenic complementation of different Mla alleles, we confirm allele-specific recognition of wheat stripe rust by Mla. Our results show that major resistance genes contribute to the host species specificity of wheat stripe rust on barley and that a shared genetic architecture underlies resistance to the adapted pathogen barley powdery mildew and non-adapted pathogen wheat stripe rust.

scholarly journals The iron-responsive genome of the chiton Acanthopleura granulata

2020 ◽  
Author(s):  
Rebecca M. Varney ◽  
Daniel I. Speiser ◽  
Carmel McDougall ◽  
Bernard M. Degnan ◽  
Kevin M. Kocot
Keyword(s):  
Iron Transport ◽  
West Indian ◽  
The Other ◽  
The West ◽  
Major Clade ◽  
Future Studies ◽  
Form And Function ◽  
Genetic Mechanisms ◽  
Molluscan Evolution ◽  
And Function

ABSTRACTMolluscs biomineralize structures that vary in composition, form, and function, prompting questions about the genetic mechanisms responsible for their production and the evolution of these mechanisms. Chitons (Mollusca, Polyplacophora) are a promising system for studies of biomineralization because they build a range of calcified structures including shell plates and spine- or scale-like sclerites. Chitons also harden the calcified teeth of their rasp-like radula with a coat of iron (as magnetite). Here we present the genome of the West Indian fuzzy chiton Acanthopleura granulata, the first from any aculiferan mollusc. The A. granulata genome contains homologs of many biomineralization genes identified previously in conchiferan molluscs. We expected chitons to lack genes previously identified from pathways conchiferans use to make biominerals like calcite and nacre because chitons do not use these materials in their shells. Surprisingly, the A. granulata genome has homologs of many of these genes, suggesting that the ancestral mollusc had a more diverse biomineralization toolkit than expected. The A. granulata genome has features that may be specialized for iron biomineralization, including a higher proportion of genes regulated directly by iron than other molluscs. A. granulata also produces two isoforms of soma-like ferritin: one is regulated by iron and similar in sequence to the soma-like ferritins of other molluscs, and the other is constitutively translated and is not found in other molluscs. The A. granulata genome is a resource for future studies of molluscan evolution and biomineralization.SIGNIFICANCE STATEMENTChitons are molluscs that make shell plates, spine- or scale-like sclerites, and iron-coated teeth. Currently, all molluscs with sequenced genomes lie within one major clade (Conchifera). Sequencing the genome of a representative from the other major clade (Aculifera) helps us learn about the origins and evolution of molluscan traits. The genome of the West Indian Fuzzy Chiton, Acanthopleura granulata, reveals chitons have homologs of many genes other molluscs use to make shells, suggesting all molluscs share some shell-making pathways. The genome of A. granulata has more genes that may be regulated directly by iron than other molluscs, and chitons produce a unique isoform of a major iron-transport protein (ferritin), suggesting that chitons have genomic specializations that contribute to their production of iron-coated teeth.

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