Mating Type Distribution and Fertility Status of Magnaporthe grisea Populations from Various Hosts in India

Production of perithecia, asci, and ascospores by Indian isolates of Magnaporthe grisea is rare and has not been found among the Southern Indian isolates of the blast pathogen. From among 138 monoconidial isolates that infect rice and other hosts, we now report the distribution of mating types (MAT1-1 and MAT1-2) of M. grisea in finger millet and paragrass (Brachiaria mutica)-infecting isolates. Twenty-eight of the 96 finger millet isolates, 5 of the 16 paragrass isolates, and none of the 26 rice isolates produced fertile perithecia in laboratory matings with fertile testers. Backcrosses of ascospore progenies to the parental M. grisea isolate but not to the tester strain resulted in fertile perithecial formation, and a further backcrossing scheme indicated definite fertility patterns of Mendelian inheritance in M. grisea.

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Cross-Compatibility and Distribution of Mating Type Alleles of the Rice Blast Fungus Magnaporthe grisea in India

Plant Disease ◽

10.1094/pdis.2000.84.6.700 ◽

2000 ◽

Vol 84 (6) ◽

pp. 700-704 ◽

Cited By ~ 24

Author(s):

B. V. Dayakar ◽

N. N. Narayanan ◽

S. S. Gnanamanickam

Keyword(s):

Mating Type ◽

Andhra Pradesh ◽

Magnaporthe Grisea ◽

Finger Millet ◽

Fragment Length Polymorphism ◽

Rice Blast Fungus ◽

Mating Types ◽

Andaman Islands ◽

Cross Compatibility ◽

Pathogenicity Tests

Two hundred twenty-seven isolates of Magnaporthe grisea isolated from blast-infected rice tissues from different states of India were tested with MAT1-1 and MAT1-2 fertile standard testers to determine their mating type. Of the 227 monoconidial isolates, 90 (39.6%) were fertile and 137 (60.4%) were infertile and did not produce perithecia when mated with any of the four testers. In the states of Meghalaya and Himachal Pradesh, both mating types were found. In the states of Andaman Islands, Andhra Pradesh, Karnataka, Haryana, and Punjab, only mating type MAT1-1 was identified. In states where MAT1-2 occurred, its frequency was low. Among the 90 fertile isolates, 40 (44.4%) produced perithecia, asci, and ascospores, and 11 of those isolates produced perithecia, asci, and ascospores with both MAT1-2 testers, KA-9 of finger millet, and GUY11 of rice origin. However, when monoconidial isolates were mated among themselves, isolates from the same field produced only barren perithecia. Pathogenicity tests of the ascospore progeny derived from crosses of field isolates and host-specific testers revealed that none of the ascospore progeny were as virulent as the parents, despite showing compatible reactions with both rice and finger millet cultivars. These results indicate that recombinant progeny may be at a selective disadvantage despite having an increased host range. This is the first report of the occurrence of high levels of fertility (24 to 52%) in rice isolates of M. grisea in different states of India. In a Southern blot analysis, 58% of 74 isolates were identified as MAT1-1 and 41% as MAT1-2. In this population, 23 Magnaporthe grisea repeat (MGR)-restriction fragment length polymorphism groups or lineages were identified. In terms of lineage composition, the 18 isolates from Meghalaya showed maximal diversity with nine lineages.

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Mating-type Distribution and Fertility Status in Magnaporthe grisea Populations from Argentina

Mycopathologia ◽

10.1007/s11046-005-4333-3 ◽

2005 ◽

Vol 160 (4) ◽

pp. 285-290 ◽

Cited By ~ 16

Author(s):

V. F. Consolo ◽

C. A. Cordo ◽

G. L. Salerno

Keyword(s):

Mating Type ◽

Magnaporthe Grisea ◽

Type Distribution ◽

Fertility Status

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Mating Type Distribution and Fertility Status in Magnaporthe grisea Populations from Turfgrasses in Georgia

Plant Disease ◽

10.1094/pdis.2003.87.4.435 ◽

2003 ◽

Vol 87 (4) ◽

pp. 435-441 ◽

Cited By ~ 18

Author(s):

L. P. Tredway ◽

K. L. Stevenson ◽

L. L. Burpee

Keyword(s):

Mating Type ◽

Tall Fescue ◽

Magnaporthe Grisea ◽

Population Analysis ◽

Low Frequency ◽

Type Distribution ◽

Fertility Status ◽

Polymerase Chain ◽

Two Populations

Populations of Magnaporthe grisea associated with tall fescue and St. Augustinegrass in Georgia were analyzed for mating type distribution and fertility status in 1999 and 2000. A polymerase chain reaction based assay for mating type was developed to facilitate population analysis. M. grisea populations from St. Augustinegrass in Georgia were dominated by the Mat1-1 mating type, whereas populations from tall fescue were dominated by Mat1-2. The opposite mating type was found in low frequency (0 to 5.7%) associated with each host. The fertility status of isolates from two populations was determined using controlled crosses in vitro. Seventy-eight Mat1-1 isolates from St. Augustinegrass were sterile in test crosses, but a single Mat1-2 isolate from St. Augustinegrass was male fertile. Of 87 Mat1-2 isolates from tall fescue, 47 were male fertile in test crosses, but 19 produced perithecia that were barren. All Mat1-1 isolates from tall fescue were sterile. Although both mating types exist in M. grisea populations from turfgrasses in Georgia, no female fertile isolates were identified in sample populations. The predominance of one mating type in eight sample populations and absence of female fertile isolates in two sample populations indicates that sexual reproduction may not occur with significant frequency in M. grisea populations associated with turfgrasses in Georgia.

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Distribution of Mating Type Alleles and Fertility Status of Magnaporthe grisea Causing Gray Leaf Spot of Perennial Ryegrass and St. Augustinegrass Turf

Plant Disease ◽

10.1094/pdis.2002.86.8.827 ◽

2002 ◽

Vol 86 (8) ◽

pp. 827-832 ◽

Cited By ~ 16

Author(s):

G. Viji ◽

W. Uddin

Keyword(s):

Mating Type ◽

Perennial Ryegrass ◽

Leaf Spot ◽

Magnaporthe Grisea ◽

Finger Millet ◽

Gray Leaf Spot ◽

Pathogen Population ◽

Fertility Status ◽

Single Location ◽

Single Mating

Isolates of Magnaporthe grisea causing gray leaf spot of perennial ryegrass (PR) (Lolium perenne) and St. Augustinegrass (SA) (Stenotaphrum secundatum) were analyzed for mating compatibility and fertility. A total of 312 isolates of M. grisea from PR and 62 isolates from SA were paired with hermaphroditic tester strains from finger millet (Eleusine coracana), rice (Oryza sativa), and wheat (Triticum aestivum). All the PR isolates belonged to a single mating type, MAT1-2. Male fertility was observed in all these isolates. Asci and ascospores were not produced regardless of their developmental stage. Of the 139 (44.6%) isolates from PR that formed perithecia with the fertile tester strains, 83 (59.7%) were highly fertile, 33 (23.7%) were intermediately fertile, and 23 (16.5%) were low in fertility. Both mating types were observed among the isolates of SA, where MAT1-1 predominated the MAT1-2 type. An equal number of male and female fertile isolates were detected among these isolates obtained from a single location; however, none of the isolates behaved as hermaphrodites. Few ascospores were produced in crosses between two isolates of SA and a finger millet tester. Of the 62 monoconidial isolates of SA tested, 19 (30.6%) isolates formed perithecia, of which 5 (26.3%) were highly fertile, 7 (36.8%) were intermediately fertile, 7 (36.8%) were low in fertility, and 43 (69.4%) were infertile. The results of this study indicate that the sexual stage may not be a significant factor contributing to the genetic variation the gray leaf spot pathogen population.

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Sexually Fertile Magnaporthe grisea Rice Pathogens in Thailand

Plant Disease ◽

10.1094/pdis.1999.83.10.939 ◽

1999 ◽

Vol 83 (10) ◽

pp. 939-943 ◽

Cited By ~ 25

Author(s):

Poonsak Mekwatanakarn ◽

Wichai Kositratana ◽

Tawatchai Phromraksa ◽

R. S. Zeigler

Keyword(s):

Mating Type ◽

Male Fertility ◽

Magnaporthe Grisea ◽

Female Sterility ◽

Diverse Populations ◽

Type Distribution ◽

Northern Regions ◽

Rice Pathogens ◽

Central Thailand

Sexual fertility and mating type distribution of Magnaporthe grisea field isolates collected in Thailand were analyzed from sites previously found to harbor diverse populations of the pathogen. Three hundred forty-one single conidium isolates of M. grisea collected from five sites in north, northeast, and central Thailand were evaluated for in vitro sexual fertility and mating type by pairing with strains of known mating type. Most isolates (67%) were infertile when crossed with the hermaphrodite tester strains; but fertile isolates of each mating type that yielded viable ascospores were detected in all sites from the northeastern and northern regions. MAT1-2 predominated over MAT1-1 in bioassay mating type. Male fertility (female sterility) predominated in fertile MAT1-1 (50 to 75%) and MAT1-2 (50 to 85%) isolates from all locations in Thailand; however, hermaphroditic and/or female fertile isolates were also detected in all but one site. Fertility, as determined by perithecia density, was low (<10 perithecia cm-2) for most isolates, although a few produced in excess of 20 perithecia cm-2.

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Genetic analyses of electrophoretic enzyme variants, mating type, and hermaphroditism in Pyricularia oryzae Cavara

Canadian Journal of Genetics and Cytology ◽

10.1139/g85-104 ◽

1985 ◽

Vol 27 (6) ◽

pp. 697-704 ◽

Cited By ~ 21

Author(s):

Hei Leung ◽

Paul H. Williams

Keyword(s):

Lactate Dehydrogenase ◽

Mating Type ◽

Rice Blast ◽

Magnaporthe Grisea ◽

Finger Millet ◽

Single Gene ◽

Pyricularia Oryzae ◽

Blast Disease ◽

Electrophoretic Variants ◽

Variant Alleles

Pyricularia oryzae (teleomorph: Magnaporthe grisea) parasitizes a variety of gramineous hosts and causes the rice blast disease worldwide. Through matings among P. oryzae isolates from rice, finger millet, and weeping lovegrass the inheritance of electrophoretic variants of six enzymes, phosphoglucomutase (PGM), phosphoglucose isomerase (PGI), glycerate-2-dehydrogenase (G2DH), malate dehydrogenase-3 (MDH-3), lactate dehydrogenase-1 (LDH-1), and lactate dehydrogenase-3 (LDH-3) was determined. All six variants were under single gene control as determined by tetrad and random spore analysis. However, at Ldh-3 and Mdh-3, there were consistent excesses of variant alleles among ascospore segregants. Preliminary data on the genetic control of hermaphroditism suggested that maleness in two Japanese rice isolates might be due to a single gene mutation. Linkage analyses among the six electrophoretic markers, mating type, and hermaphroditism suggested loose linkage between Pgm and G2dh with a recombination frequencies of 43.0%.Key words: linkage, Magnaporthe grisea, rice blast fungus.

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Mating type distribution using a multiplex PCR mating assay and fertility status inDidymella rabieiin chickpea-growing areas in Iran

Archives of Phytopathology and Plant Protection ◽

10.1080/03235408.2013.821806 ◽

2014 ◽

Vol 47 (9) ◽

pp. 1030-1041

Author(s):

Farshid Mahmodi ◽

Ziaeddin Banihashemi ◽

Jugah Kadir ◽

Adam Puteh ◽

Abbas Nasehi

Keyword(s):

Multiplex Pcr ◽

Mating Type ◽

Type Distribution ◽

Fertility Status

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Species and Mating-Type Distribution of Tapesia yallundae and T. acuformis and Occurrence of Apothecia in the U.S. Pacific Northwest

Phytopathology ◽

10.1094/phyto.2002.92.7.703 ◽

2002 ◽

Vol 92 (7) ◽

pp. 703-709 ◽

Cited By ~ 20

Author(s):

G. W. Douhan ◽

T. D. Murray ◽

P. S. Dyer

Keyword(s):

Pacific Northwest ◽

Mating Type ◽

Spatial Scales ◽

Mating Types ◽

Field Plot ◽

Type Distribution ◽

Predominant Species ◽

Tapesia Yallundae ◽

Wheat Stubble ◽

The U.S

Eyespot of wheat is caused by the discomycete fungi Tapesia yallundae and T. acuformis. T. yallundae is considered the most important causal agent of the disease in this region but no apothecia of either species have been found in the U.S. Pacific Northwest (PNW). Two compatible isolates of T. yallundae from the PNW were used to inoculate a field plot in the fall of 1998 and apothecia developed in the spring and fall of 2000 on standing wheat stubble. In the spring of 2000, wheat stubble from eight naturally infected fields was examined for the presence of apothecia of T. yallundae and T. acuformis. Apothecia of T. acuformis were found in two fields but no apothecia of T. yallundae were found. This is the first report of apothecia of the eyespot pathogens occurring in the PNW. Species and mating-type distribution of T. yallundae and T. acuformis in the PNW were determined from 817 isolates collected from diseased wheat over 3 years at spatial scales ranging from within fields to across states. In all, 460 isolates were identified as T. yallundae and 357 isolates were identified as T. acuformis with MAT1-1/MAT1-2 ratios not significantly different from 1:1 based on χ2 tests at most scales tested. The apparent increase in frequency of T. acuformis from previous surveys may indicate a shift in the predominant species causing eyespot. The occurrence of apothecia under field conditions, along with the widespread distribution of mating types of both species, suggests that sexual reproduction may be occurring in both species.

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