Host Range, Mating Type, and Fertility of<i>Pyricularia grisea</i>from Wheat in Brazil

Urashima, Alfredo Seiiti; Igarashi, Seiji; Katô, Hajime

doi:10.1094/pd-77-1211

Cited by 182 publications

(158 citation statements)

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“…This mechanism may be more likely with the wheat blast pathogen in Brazil. Studies have characterized M. grisea from wheat as highly fertile sexually, hermaphroditic, sexually compatible with isolates from other hosts (Urashima et al, 1993), and both MAT1-1 and MAT1-2 mating types exist in a single field (Bruno & Urashima, 2001). The virulence diversity of isolates would also explain why some cultivars resistant in previous studies, BH1146, BR11, CNT8 (Igarashi et al, 1986;Barros et al, 1989;Goulart & Paiva, 1993) were not resistant in the present work.…”

Section: Discussionmentioning

confidence: 99%

Resistance spectra of wheat cultivars and virulence diversity of Magnaporthe grisea isolates in Brazil

Lavorent²,

et al. 2004

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Seventy-two monoconidial isolates of Magnaporthe grisea were obtained from the States of Mato Grosso do Sul and Paraná. The isolates were inoculated on seedlings of 20 wheat (Triticum aestivum) cultivars under greenhouse conditions. The virulence diversity of M. grisea was assessed based on compatible and incompatible reactions of leaf blast on wheat cultivars. Fifty-four distinct virulence patterns were identified on test cultivars among the isolates collected from the two wheat growing States. Sixteen of these isolates corresponding to 22.2% showed similar virulence pattern. None of the wheat cultivars was resistant to all isolates of M. grisea, but the cultivars differed in degree of resistance as measured by the relative spectrum of resistance (RSR) and disease index (DI). Among the cultivars the RSR ranged from 0 to 53.3% and DI from 0.4662 to 0.9662 (0 to 1 scale). The wheat cultivar BR18 exhibited a broad resistance spectrum in relation to the rest of the tested cultivars to the isolates of M. grisea, and can be used in wheat resistance breeding.

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Section: Discussionmentioning

confidence: 99%

Resistance spectra of wheat cultivars and virulence diversity of Magnaporthe grisea isolates in Brazil

Lavorent²,

et al. 2004

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“…However, seed infection seems to play only a minor role in the epidemiology of the disease because spike infection comes from the air-borne conidia mainly from several secondary hosts (Prabhu et al 1992;Urashima et al 1993). Several grass weeds (Cenchrus echinatus, Eleusine indica, Digitaria sanguinalis, Brachiaria plantaginea, Echinocloa crusgalli, Pennisetum setosum, Hyparrhenia rufa and Rhynchelytrum roseum) occur commonly in wheat and rice fields of Brazil and are secondary hosts of Pyricularia, but their role in the epidemiology of wheat blast is not well understood (Prabhu et al 1992).…”

Section: Seed and Secondary Hosts As Source Of Primary Inoculummentioning

confidence: 99%

Pyricularia blast - a threat to wheat cultivation

Kohli¹,

Mehta²,

Rodríguez-Guzmán³

et al. 2011

CZECH J GENET PLANT

169

175

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Wheat blast disease caused by Pyricularia grisea (telemorph Magnaporthe grisea) has become a serious restriction on increasing the area and production of the crop, especially in the tropical parts of the Southern Cone Region of South America. First identified in 1985 in the State of Paraná in Brazil, it has become an endemic disease in the low lying Santa Cruz region of Bolivia, south and south-eastern Paraguay, and central and southern Brazil in recent years. Severe infections have also been observed in the summer planted wheat crop in north-eastern Argentina. So far, only sporadic infections have been seen in Uruguay, especially during the wet and warm years. Spike infection (often confused with Fusarium head blight infection) is the most notable symptom of the disease and capable of causing over 40% production losses. However, under severe infection, the loss of production can be almost complete in susceptible varieties. Wheat blast is mainly a spike disease but can also produce lesions on all the above ground parts of the plant under certain conditions. Depending upon the point of the infection on the rachis, the disease can kill the spike partially or fully. The infected portion of the spike dries out without producing any grain which can be visibly distinguished from the healthy portion. While virulence diversity in the fungus has been reported in the literature and is under further exploration, genetic resistance in the host species has been more difficult to identify. Earlier, Brazilian cultivars such as BH 1146, CNT 8, several IAC and OCEPAR selections were credited as demonstrating different levels of field resistance, but this was not confirmed under artificial inoculation studies. However, other cultivars such as BR18, IPR 85, CD 113, have shown moderate levels of resistance over the years in many locations. Recently, several cultivars and advanced lines derived from the CIMMYT line, Milan, have been observed to carry a high level of resistance to blast disease throughout the endemic region. However, to date, the genetic basis of this resistance is not very clear due to extreme variation in the pathogen. Cultivars showing complete resistance against a few isolates under controlled conditions in the glasshouse, may or may not show field resistance in commercial cultivation. Due to an increase of the area under Milan based resistant wheat cultivars in Bolivia, Brazil and Paraguay, it needs to be combined with other sources of resistance urgently to prevent the selection of a virulent pathotype in the fungus. Besides genetic resistance, avoidance of early dates of seeding and chemical control can reduce the disease severity. Fungicides combining triazols with strobilurins can, under some situations, be effective in disease control at the heading stage. Even when all components of integrated disease management of wheat blast are not in place yet, it is seen as an essential strategy to reduce production losses in this region. Given the threat that the blast disease may pose to world wheat growin...

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“…Recombinação sexual em P. grisea era considerada extremamente rara porque isolados de arroz coletados no campo tinham baixa fertilidade sexual (10,15) e os estudos sobre a distribuição de tipos compatíveis mostraram que somente um tipo compatível ("mating type") predominava numa determinada região rizícola (10,29). No entanto, recentes descobertas de isolados de alta fertilidade, hermafrodita, de ambos "mating type", próximo ao centro de origem do arroz sugerem que a recombinação sexual pode contribuir para a variabilidade genética desse fungo (5, 11,13 (21). Por outro lado, isolados do trigo mostraram alta habilidade de cruzamento sexual, sendo hermafroditas, com presença de ambos os tipos compatíveis num mesmo campo ao mesmo tempo (2,21).…”

Section: Pyricularia Grisea Sacc (Teleomorfa Magnaporte Griseaunclassified

“…Por outro lado, isolados do trigo mostraram alta habilidade de cruzamento sexual, sendo hermafroditas, com presença de ambos os tipos compatíveis num mesmo campo ao mesmo tempo (2,21). Devido a capacidade de P. grisea de produzir peritécio envolver características complexas (25), a fertilidade e capacidade de cruzamento foram usadas como critério para diferenciar os patógenos causadores da brusone do trigo e do arroz (21). Poucos trabalhos enfocando os aspectos sexuais de isolados da brusone de outros hospedeiros no Brasil tem sido realizados (2,21).…”

Section: Pyricularia Grisea Sacc (Teleomorfa Magnaporte Griseaunclassified

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Caracterização, compatibilidade e ocorrência de reprodução sexual entre isolados de Pyricularia grisea de diferentes hospedeiros

Galbieri

Urashima

2008

Summa phytopathol.

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A brusone, causada por Pyricularia grisea (teleomorfa Magnaphorthe grisea), possui uma ampla gama de hospedeiros. No Brasil, arroz, trigo, triticale e cevada são as culturas que sofrem quedas significativas de produtividade devido ao ataque desse patógeno. Além desses cereais, outras gramíneas também têm apresentado sintomas dessa doença. Os objetivos dessa pesquisa foram: a) caracterizar sexualmente isolados de P. grisea desses hospedeiros baseado na determinação do "mating type", fertilidade, sexualidade, compatibilidade sexual, b) analisar o grau de compatibilidade sexual entre isolados de brusone de trigo e de outras gramíneas, c) estudar a ocorrência da reprodução sexual em isolados de trigo. Os resultados obtidos através de ensaios "in vitro" constataram: 1) compatibilidade sexual de P. grisea do trigo com Bromus catharticus, Phalaris canariensis e X. triticosecal; 2) desbalanço entre porcentagem de MAT1-1 e MAT1-2, com predominância de MAT1-1 na população de P. grisea do trigo; 3) existência de um campo de isolados de trigo com baixa habilidade de cruzamento; 4) baixa possibilidade de ocorrência de reprodução sexual de P. grisea em campos de trigo, mesmo com existência de ambos "mating type" num mesmo campo.

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Host Range, Mating Type, and Fertility ofPyricularia griseafrom Wheat in Brazil

Cited by 182 publications

References 0 publications

Resistance spectra of wheat cultivars and virulence diversity of Magnaporthe grisea isolates in Brazil

Resistance spectra of wheat cultivars and virulence diversity of Magnaporthe grisea isolates in Brazil

Pyricularia blast - a threat to wheat cultivation

Caracterização, compatibilidade e ocorrência de reprodução sexual entre isolados de Pyricularia grisea de diferentes hospedeiros

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