Identification of an Avirulence Gene in the Fungus Magnaporthe grisea Corresponding to a Resistance Gene at the Pik Locus

A rice isolate of Magnaporthe grisea collected from China was avirulent on rice cvs. Hattan 3 and 13 other Japanese rice cultivars. The rice cv. Hattan 3 is susceptible to almost all Japanese blast fungus isolates from rice. The genetic basis of avirulence in the Chinese isolate on Japanese rice cultivars was studied using a cross between the Chinese isolate and a laboratory isolate. The segregation of avirulence or virulence was studied in 185 progeny from the cross, and monogenic control was demonstrated for avirulence to the 14 rice cultivars. The resistance gene that corresponds to the avirulence gene (Avr-Hattan 3) is thought to be located at the Pik locus. Resistance and susceptibility in response to the Chinese isolate in F3 lines of a cross of resistant and susceptible rice cultivars were very similar to the Pik tester isolate, Ken54-20. Random amplified polymorphic DNA markers and restriction fragment length polymorphism markers from genetic maps of the fungus were used to construct a partial genetic map of Avr-Hattan 3. We obtained several flanking markers and one co-segregated marker of Avr-Hattan 3 in the 144 mapping population.

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Gain of Virulence Caused by Insertion of a Pot3 Transposon in a Magnaporthe grisea Avirulence Gene

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.5.671 ◽

2001 ◽

Vol 14 (5) ◽

pp. 671-674 ◽

Cited By ~ 128

Author(s):

Seogchan Kang ◽

Marc Henri Lebrun ◽

Leonard Farrall ◽

Barbara Valent

Keyword(s):

Disease Resistance ◽

Resistance Gene ◽

Magnaporthe Grisea ◽

Rice Cultivar ◽

Avirulence Gene ◽

Disease Resistance Gene ◽

Rice Cultivars

The avirulence gene AVR-Pita in Magnaporthe grisea prevents the fungus from infecting rice cultivars carrying the disease resistance gene Pi-ta. Insertion of Pot3 transposon into the promoter of AVR-Pita caused the gain of virulence toward Yashiro-mochi, a rice cultivar containing Pi-ta, which demonstrated the ability of Pot3 to move within the M. grisea genome. The appearance of Pot3 in M. grisea seems to predate the diversification of various host-specific forms of the fungus.

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A Consensus Map for Loblolly Pine (Pinus taeda L.). I. Construction and Integration of Individual Linkage Maps From Two Outbred Three-Generation Pedigrees

Genetics ◽

10.1093/genetics/151.1.321 ◽

1999 ◽

Vol 151 (1) ◽

pp. 321-330 ◽

Cited By ~ 4

Author(s):

Mitchell M Sewell ◽

Bradley K Sherman ◽

David B Neale

Keyword(s):

Pinus Taeda ◽

Loblolly Pine ◽

Fragment Length Polymorphism ◽

Random Amplified Polymorphic Dna ◽

Mapping Function ◽

Genetic Maps ◽

Linkage Data ◽

Linkage Maps ◽

Consensus Map ◽

Pinus Taeda L

Abstract A consensus map for loblolly pine (Pinus taeda L.) was constructed from the integration of linkage data from two unrelated three-generation outbred pedigrees. The progeny segregation data from restriction fragment length polymorphism, random amplified polymorphic DNA, and isozyme genetic markers from each pedigree were recoded to reflect the two independent populations of parental meioses, and genetic maps were constructed to represent each parent. The rate of meiotic recombination was significantly greater for males than females, as was the average estimate of genome length for males {1983.7 cM [Kosambi mapping function (K)]} and females [1339.5 cM(K)]. The integration of individual maps allows for the synthesis of genetic information from independent sources onto a single consensus map and facilitates the consolidation of linkage groups to represent the chromosomes (n = 12) of loblolly pine. The resulting consensus map consists of 357 unique molecular markers and covers ∼1300 cM(K).

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Identification and fine mapping of Pi33, the rice resistance gene corresponding to the Magnaporthe grisea avirulence gene ACE1

Theoretical and Applied Genetics ◽

10.1007/s00122-003-1349-2 ◽

2003 ◽

Vol 107 (6) ◽

pp. 1139-1147 ◽

Cited By ~ 88

Author(s):

R. Berruyer ◽

H. Adreit ◽

J. Milazzo ◽

S. Gaillard ◽

A. Berger ◽

...

Keyword(s):

Resistance Gene ◽

Fine Mapping ◽

Magnaporthe Grisea ◽

Avirulence Gene

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A gene controlling sex in grapevines placed on a molecular marker-based genetic map

Genome ◽

10.1139/g99-136 ◽

2000 ◽

Vol 43 (2) ◽

pp. 333-340 ◽

Cited By ~ 88

Author(s):

M A Dalbó ◽

G N Ye ◽

N F Weeden ◽

H Steinkellner ◽

K M Sefc ◽

...

Keyword(s):

Molecular Marker ◽

Dna Markers ◽

Fragment Length Polymorphism ◽

Random Amplified Polymorphic Dna ◽

Basic Number ◽

Genetic Maps ◽

Hybrid Population ◽

Linkage Groups ◽

Starting Point ◽

Map Distance

Genetic maps of Vitis (2n = 38) have been constructed from an interspecific hybrid population of 58 seedlings of the cross 'Horizon' ('Seyval' × 'Schuyler') × Illinois 547-1 (V. cinerea B9 × V. rupestris B38). The maps were initially constructed based on 277 RAPD (random amplified polymorphic DNA) markers using a double-pseudotestcross strategy. Subsequently, 25 microsatellites, 4 CAPS (cleaved amplified polymorphic sequence), and 12 AFLP (amplified fragment length polymorphism) markers were added to the maps. Another 120 markers, mostly those segregating 3:1, were also assigned but not positioned on the linkage groups in the two maps. The 'Horizon' map consisted of 153 markers covering 1199 cM, with an average map distance of 7.6 cM between markers. The Illinois 547-1 map had 179 markers covering 1470 cM, with an average map distance of 8.1 cM. There were 20 linkage groups in each map, one more than the basic number of chromosomes in grapes. Ten linkage groups in each map were identified as homologous using 16 microsatellite and 2 CAPS markers polymorphic in both parents. A single locus controlling sex in grapes mapped close to a microsatellite marker. These maps provide enough coverage of the genome for QTL (quantitative trait loci) analysis and as a starting point for positional gene cloning in grapes. Key words: Vitis, RAPD, microsatellite, SSR, CAPS.

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An anchored AFLP- and retrotransposon-based map of diploid Avena

Genome ◽

10.1139/g00-037 ◽

2000 ◽

Vol 43 (5) ◽

pp. 736-749 ◽

Cited By ~ 35

Author(s):

Gong-Xin Yu ◽

Roger P Wise

Keyword(s):

Resistance Gene ◽

Length Polymorphism ◽

Fragment Length ◽

Rust Resistance ◽

Fragment Length Polymorphism ◽

Random Amplified Polymorphic Dna ◽

Crown Rust ◽

Crown Rust Resistance ◽

Resistance Specificity ◽

Specific Amplification

A saturated genetic map of diploid oat was constructed based on a recombinant inbred (RI) population developed from a cross between Avena strigosa (Cereal Introduction, C.I. 3815) and A. wiestii (C.I. 1994). This 513-locus map includes 372 AFLP (amplified fragment length polymorphism) and 78 S-SAP (sequence-specific-amplification polymorphism) markers, 6 crown-rust resistance loci, 8 resistance-gene analogs (RGAs), one morphological marker, one RAPD (random amplified polymorphic DNA) marker, and is anchored by 45 grass-genome RFLP (restriction fragment length polymorphism) markers. This new A. strigosa × A. wiestii RI map is colinear with a diploid Avena map from an A. atlantica × A. hirtula F2 population. However, some linkage blocks were rearranged as compared to the RFLP map derived from the progenitor A. strigosa × A. wiestii F2 population. Mapping of Bare-1-like sequences via sequence-specific AFLP indicated that related retrotransposons had considerable heterogeneity and widespread distribution in the diploid Avena genome. Novel amplified fragments detected in the RI population suggested that some of these retrotransposon-like sequences are active in diploid Avena. Three markers closely linked to the Pca crown-rust resistance cluster were identified via AFLP-based bulk-segregant analysis. The derived STS (sequence-tagged-site) marker, Agx4, cosegregates with Pc85, the gene that provides resistance specificity to crown-rust isolate 202 at the end of the cluster. This framework map will be useful in gene cloning, genetic mapping of qualitative genes, and positioning QTL (quantitative trait loci) of agricultural importance.Key words: AFLP, Bare-1 retrotransposon, sequence-specific-amplification polymorphism (S-SAP), resistance-gene analog, crown-rust resistance, Pca, Gramineae, grass anchor probe.

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DNA markers for downy mildew resistance genes in sorghum

Genome ◽

10.1139/g95-106 ◽

1995 ◽

Vol 38 (4) ◽

pp. 823-826 ◽

Cited By ~ 21

Author(s):

P. S. Bhavanishankara Gowda ◽

Richard A. Frederiksen ◽

Clint W. Magill ◽

Guo-Wei Xu

Keyword(s):

Downy Mildew ◽

Resistance Gene ◽

Dna Markers ◽

Fragment Length Polymorphism ◽

Mapping Population ◽

Random Amplified Polymorphic Dna ◽

Downy Mildew Resistance ◽

Mildew Resistance ◽

Sorghum Line ◽

Rflp Rapd

The random amplified polymorphic DNA technique was used to find markers for a downy mildew resistance gene in sorghum. Of the 674 random primers screened for polymorphism, 2 amplified fragments were linked to a downy mildew resistance gene in sorghum line SC414. Utilization of an existing restriction fragment length polymorphism mapping population (IS3620C × BTx623) also revealed two markers that are linked to a different resistance gene in another sorghum line, BTx623.Key words: sorghum, downy mildew, RFLP, RAPD.

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Expression of Magnaporthe grisea Avirulence Gene ACE1 Is Connected to the Initiation of Appressorium-Mediated Penetration

Eukaryotic Cell ◽

10.1128/ec.00330-05 ◽

2007 ◽

Vol 6 (3) ◽

pp. 546-554 ◽

Cited By ~ 44

Author(s):

Isabelle Fudal ◽

Jérôme Collemare ◽

Heidi U. Böhnert ◽

Delphine Melayah ◽

Marc-Henri Lebrun

Keyword(s):

Host Plant ◽

Magnaporthe Grisea ◽

Plant Cell Wall ◽

Current Control ◽

Camp Signaling ◽

Avirulence Gene ◽

Rice Cultivars ◽

Avirulence Genes ◽

Specific Expression ◽

Melanin Biosynthesis

ABSTRACT Magnaporthe grisea is responsible for a devastating fungal disease of rice called blast. Current control of this disease relies on resistant rice cultivars that recognize M. grisea signals corresponding to specific secreted proteins encoded by avirulence genes. The M. grisea ACE1 avirulence gene differs from others, since it controls the biosynthesis of a secondary metabolite likely recognized by rice cultivars carrying the Pi33 resistance gene. Using a transcriptional fusion between ACE1 promoter and eGFP, we showed that ACE1 is only expressed in appressoria during fungal penetration into rice and barley leaves, onion skin, and cellophane membranes. ACE1 is almost not expressed in appressoria differentiated on Teflon and Mylar artificial membranes. ACE1 expression is not induced by cellophane and plant cell wall components, demonstrating that it does not require typical host plant compounds. Cyclic AMP (cAMP) signaling mutants ΔcpkA and Δmac1 sum1-99 and tetraspanin mutant Δpls1::hph differentiate melanized appressoria with normal turgor but are unable to penetrate host plant leaves. ACE1 is normally expressed in these mutants, suggesting that it does not require cAMP signaling or a successful penetration event. ACE1 is not expressed in appressoria of the buf1::hph mutant defective for melanin biosynthesis and appressorial turgor. The addition of hyperosmotic solutes to buf1::hph appressoria restores appressorial development and ACE1 expression. Treatments of young wild-type appressoria with actin and tubulin inhibitors reduce both fungal penetration and ACE1 expression. These experiments suggest that ACE1 appressorium-specific expression does not depend on host plant signals but is connected to the onset of appressorium-mediated penetration.

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Evolution of an Avirulence Gene, AVR1-CO39, Concomitant with the Evolution and Differentiation of Magnaporthe oryzae

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-18-1148 ◽

2005 ◽

Vol 18 (11) ◽

pp. 1148-1160 ◽

Cited By ~ 38

Author(s):

Yukio Tosa ◽

Jun Osue ◽

Yukiko Eto ◽

Hong-Sik Oh ◽

Hitoshi Nakayashiki ◽

...

Keyword(s):

Resistance Gene ◽

Ribosomal Dna ◽

Magnaporthe Oryzae ◽

Dna Sequences ◽

Early Stage ◽

Pyricularia Oryzae ◽

Avirulence Gene ◽

Rice Cultivars ◽

Blast Fungus ◽

Specific Subgroup

The significance of AVR1-CO39, an avirulence gene of the blast fungus corresponding to Pi-CO39(t) in rice cultivars, during the evolution and differentiation of the blast fungus was evaluated by studying its function and distribution in Pyricularia spp. When the presence or absence of AVR1-CO39 was plotted on a dendrogram constructed from ribosomal DNA sequences, a perfect parallelism was observed between its distribution and the phylogeny of Pyricularia isolates. AVR1-CO39 homologs were exclusively present in one species, Pyricularia oryzae, suggesting that AVR1-CO39 appeared during the early stage of evolution of P. oryzae. Transformation assays showed that all the cloned homologs tested are functional as an avirulence gene, indicating that selection has maintained their function. Nevertheless, Oryza isolates (isolates virulent on Oryza spp.) in P. oryzae exceptionally noncarriers of AVR1-CO39. All Oryza isolates suffered from one of the two types of known rearrangements at the Avr1-CO39 locus (i.e., G type and J type). These types were congruous to the two major lineages of Oryza isolates from Japan determined by MGR586 and MAGGY. These results indicate that AVR1-CO39 was lost during the early stage of evolution of the Oryza-specific subgroup of P. oryzae. Interestingly, its corresponding resistance gene, Pi-CO39(t), is not widely distributed in Oryza spp.

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Analysis of a detailed genetic linkage map of Lactuca sativa (lettuce) constructed from RFLP and RAPD markers.

Genetics ◽

10.1093/genetics/136.4.1435 ◽

1994 ◽

Vol 136 (4) ◽

pp. 1435-1446

Author(s):

R V Kesseli ◽

I Paran ◽

R W Michelmore

Keyword(s):

Lactuca Sativa ◽

Genetic Linkage ◽

Rapd Markers ◽

Genetic Linkage Map ◽

Fragment Length Polymorphism ◽

Random Amplified Polymorphic Dna ◽

Genetic Maps ◽

Morphological Markers ◽

Linkage Groups ◽

F2 Population

Abstract A detailed genetic map has been constructed from the F2 population of a single intraspecific cross of Lactuca sativa (n = 9). It comprises 319 loci, including 152 restriction fragment length polymorphism (RFLP), 130 random amplified polymorphic DNA (RAPD), 7 isozyme, 19 disease resistance, and 11 morphological markers. Thirteen major, four minor linkage groups and several unlinked markers are identified for this genome which is estimated to be approximately 1950 cM. RFLP and RAPD markers show similar distributions throughout the genome and identified similar levels of polymorphism. RAPD loci were much quicker to identify but more difficult to order. Procedures for generating accurate genetic maps and their limitations are described.

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Genetic and Molecular Analyses in Crosses of Race 2 and Race 7 of Albugo candida

Phytopathology ◽

10.1094/phyto.2003.93.8.959 ◽

2003 ◽

Vol 93 (8) ◽

pp. 959-965 ◽

Cited By ~ 14

Author(s):

Tika B. Adhikari ◽

Jean Q. Liu ◽

Snehlata Mathur ◽

Chunren X. Wu ◽

S. Roger Rimmer

Keyword(s):

Dna Markers ◽

Fragment Length Polymorphism ◽

Random Amplified Polymorphic Dna ◽

Dominant Gene ◽

Avirulence Gene ◽

Susceptible Host ◽

Albugo Candida ◽

White Rust ◽

Differential Cultivars ◽

Race 2

The inheritance of avirulence and polymorphic molecular markers in Albugo candida, the cause of white rust of crucifers, was studied in crosses of race 2 (Ac2), using isolates MiAc2-B1 or MiAc2-B5 (metalaxyl-insensitive and virulent to Brassica juncea cv. Burgonde) with race 7 (Ac7), using isolate MsAc7-A1 (metalaxyl-sensitive and virulent to B. rapa cv. Torch). Hybrids were obtained via co-inoculation onto a common susceptible host. Putative F1 progeny were selfed to produce F2 progeny. The parents and F1 progeny were examined for virulence on the differential cultivars B. juncea cv. Burgonde and B. rapa cv. Torch. Segregation of avirulence or virulence of F2 populations was analyzed on cv. Torch. Putative F1 hybrids were confirmed by random amplified polymorphic DNA markers specific for each parent. Avirulence or virulence of F 2 progeny to B. rapa cv. Torch suggested 3:1 in each of three populations, supporting the hypothesis of a single dominant avirulence gene. Amplified fragment length polymorphism markers also segregated in regular Mendelian fashion among F2 progeny derived from two F1 hybrids (Cr2-5 and Cr2-7) of Cross-2. This first putative avirulence gene in A. candida was designated AvrAc1. These results suggest that a single dominant gene controls avirulence in race Ac2 to B. rapa cv. Torch and provides further evidence for the gene-for-gene relationship in the Albugo-Brassica pathosystem.

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