The Experts below are selected from a list of 1701 Experts worldwide ranked by ideXlab platform
Karlheinz Kogel - One of the best experts on this subject based on the ideXlab platform.
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the white barley mutant albostrians shows a supersusceptible but symptomless interaction phenotype with the hemibiotrophic fungus Bipolaris sorokiniana
Molecular Plant-microbe Interactions, 2004Co-Authors: Patrick Schafer, Ralph Huckelhoven, Karlheinz KogelAbstract:Bipolaris sorokiniana (teleomorph: Cochliobolus sativus) is a cereal pathogen of increasing global concern, with most significance in Asiatic cropping systems. In order to gain insight into the mechanism of host resistance, we studied fungal development on the supersusceptible barley mutant albostrians and its parent cv. Haisa. A microscopic dissection of early fungal growth on Haisa and green albostrians leaves revealed a distinct epidermis-localized biotrophic and a mesophyll-based necrotrophic phase. White, green, and striped white-green albostrians leaves showed extreme differences in disease development. When comparing cellular defense responses, we found restriction of fungal spreading after successful infection of host mesophyll tissue to be the most important mecha nism limiting outbreak of the disease. Colonization of susceptible green leaves, but not extreme colonization of supersusceptible white albostrians leaves, was associated with macroscopically visible lesion formation and mesophyll accum...
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Bipolaris sorokiniana a cereal pathogen of global concern cytological and molecular approaches towards better control
Molecular Plant Pathology, 2002Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Patrick Schafer, Gregor Langen, Helmut Baltruschat, Elke Stein, Subramaniam Nagarajan, Karlheinz KogelAbstract:Summary Bipolaris sorokiniana (teleomorph Cochliobolus sativus ) is the causal agent of common root rot, leaf spot disease, seedling blight, head blight, and black point of wheat and barley. The fungus is one of the most serious foliar disease constraints for both crops in warmer growing areas and causes significant yield losses. High temperature and high relative humidity favour the outbreak of the disease, in particular in South Asia's intensive ‘irrigated wheat–rice’ production systems. In this article, we review the taxonomy and worldwide distribution, as well as strategies to counteract the disease as an emerging threat to cereal production systems. We also review the current understanding of the cytological and molecular aspects of the interaction of the fungus with its cereal hosts, which makes B. sorokiniana a model organism for studying plant defence responses to hemibiotrophic pathogens. The contrasting roles of cell death and H 2O2 generation in plant defence during biotrophic and necrotrophic fungal growth phases are discussed.
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mlo5 a resistance gene effective against a biotrophic pathogen blumeria graminis fsp hordei confers enhanced susceptibility of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus
2002Co-Authors: Justus Liebig, Jagdish Kumar, Ralph Huckelhoven, Lorant Kiraly, Karlheinz KogelAbstract:The barley resistance gene mlo5 determines race non-specific resistance to the biotrophic powdery mildew pathogen Blumeria graminis f.sp. hordei. On the other hand, we have shown that barley lines that contain the mlo5 gene display enhanced susceptibility to the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus) and its toxic culture filtrate (Kumar et al. 2001). Enhanced susceptibility to necrotic disease symptoms was linked to increased accumulation of hydrogen peroxide (H2O2), a reactive oxygen intermediate. In addition, increased accumulation of transcripts of a barley pathogenesis-related gene (PR1- b) and slight increases in expression of two antioxidant genes, a glutathione S transferase and an ascorbate peroxidase occurred in association with enhanced cell/tissue death and H2O2 accumulation. These results might reflect an unsuccessful attempt by infected mlo5-barley to suppress necrotic disease symptoms and support the hypothesis that the barley Mlo gene product functions as a negative regulator of cell death. Therefore, a compromised Mlo pathway confers effective control of the biotrophic powdery mildew pathogen but not of the necrotroph B. sorokiniana, demonstrating the necessity of different host defense strategies in response to pathogens with different lifestyles (biotroph vs. necrotroph).
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a compromised mlo pathway affects the response of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus and its toxins
Phytopathology, 2001Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Ulrich Beckhove, Subrahmaniam Nagarajan, Karlheinz KogelAbstract:ABSTRACT In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, ...
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a compromised mlo pathway affects the response of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus and its toxins
Phytopathology, 2001Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Ulrich Beckhove, Subrahmaniam Nagarajan, Karlheinz KogelAbstract:ABSTRACT In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, were also more sensitive to Bipolaris sorokiniana toxins than wild-type barley but showed less symptoms than mlo5 parents. Fungal culture filtrates induced an H2O2 burst in all mutants, whereas wild-type (Mlo) barley was less sensitive. The results support the hypothesis that the barley Mlo gene product functions as a suppresser of cell death. Therefore, a compromised Mlo pathway is effective for control of biotrophic powdery mildew fungus but not for necrotrophic Bipolaris sorokiniana. We discuss the problem of finding resistance traits that are effective against both biotrophic and necrotrophic pathogens with emphasis on the role of the anti-oxidative system of plant cells.
Tingyu Duan - One of the best experts on this subject based on the ideXlab platform.
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an arbuscular mycorrhizal fungus and epichloe festucae var lolii reduce Bipolaris sorokiniana disease incidence and improve perennial ryegrass growth
Mycorrhiza, 2018Co-Authors: Fang Li, Michael J Christensen, Yanzhong Li, Tingyu DuanAbstract:Leaf spot of perennial ryegrass (Lolium perenne) caused by Bipolaris sorokiniana is an important disease in temperate regions of the world. We designed this experiment to test for the combined effects of the arbuscular mycorrhizal (AM) fungus Claroideoglomus etunicatum and the grass endophyte fungus Epichloe festucae var. lolii on growth and disease occurrence in perennial ryegrass. The results show that C. etunicatum increased plant P uptake and total dry weight and that this beneficial effect was slightly enhanced when in association with the grass endophyte. The presence in plants of both the endophyte and B. sorokiniana decreased AM fungal colonization. Plants inoculated with B. sorokiniana showed the typical leaf spot symptoms 2 weeks after inoculation and the lowest disease incidence was with plants that were host to both C. etunicatum and E. festucae var. lolii. Plants with these two fungi had much higher activity of peroxidases (POD), superoxide dismutase (SOD) and catalase (CAT) and lower values of malondialdehyde (MDA) and hydrogen peroxide (H2O2). The AM fungus C. etunicatum and the grass endophyte fungus E. festucae var. lolii have the potential to promote perennial ryegrass growth and resistance to B. sorokiniana leaf spot.
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an arbuscular mycorrhizal fungus and epichloe festucae var lolii reduce Bipolaris sorokiniana disease incidence and improve perennial ryegrass growth
Mycorrhiza, 2018Co-Authors: Yane Guo, Michael J Christensen, Ping Gao, Tingyu DuanAbstract:Leaf spot of perennial ryegrass (Lolium perenne) caused by Bipolaris sorokiniana is an important disease in temperate regions of the world. We designed this experiment to test for the combined effects of the arbuscular mycorrhizal (AM) fungus Claroideoglomus etunicatum and the grass endophyte fungus Epichloe festucae var. lolii on growth and disease occurrence in perennial ryegrass. The results show that C. etunicatum increased plant P uptake and total dry weight and that this beneficial effect was slightly enhanced when in association with the grass endophyte. The presence in plants of both the endophyte and B. sorokiniana decreased AM fungal colonization. Plants inoculated with B. sorokiniana showed the typical leaf spot symptoms 2 weeks after inoculation and the lowest disease incidence was with plants that were host to both C. etunicatum and E. festucae var. lolii. Plants with these two fungi had much higher activity of peroxidases (POD), superoxide dismutase (SOD) and catalase (CAT) and lower values of malondialdehyde (MDA) and hydrogen peroxide (H2O2). The AM fungus C. etunicatum and the grass endophyte fungus E. festucae var. lolii have the potential to promote perennial ryegrass growth and resistance to B. sorokiniana leaf spot.
Jagdish Kumar - One of the best experts on this subject based on the ideXlab platform.
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Bipolaris sorokiniana a cereal pathogen of global concern cytological and molecular approaches towards better control
Molecular Plant Pathology, 2002Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Patrick Schafer, Gregor Langen, Helmut Baltruschat, Elke Stein, Subramaniam Nagarajan, Karlheinz KogelAbstract:Summary Bipolaris sorokiniana (teleomorph Cochliobolus sativus ) is the causal agent of common root rot, leaf spot disease, seedling blight, head blight, and black point of wheat and barley. The fungus is one of the most serious foliar disease constraints for both crops in warmer growing areas and causes significant yield losses. High temperature and high relative humidity favour the outbreak of the disease, in particular in South Asia's intensive ‘irrigated wheat–rice’ production systems. In this article, we review the taxonomy and worldwide distribution, as well as strategies to counteract the disease as an emerging threat to cereal production systems. We also review the current understanding of the cytological and molecular aspects of the interaction of the fungus with its cereal hosts, which makes B. sorokiniana a model organism for studying plant defence responses to hemibiotrophic pathogens. The contrasting roles of cell death and H 2O2 generation in plant defence during biotrophic and necrotrophic fungal growth phases are discussed.
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mlo5 a resistance gene effective against a biotrophic pathogen blumeria graminis fsp hordei confers enhanced susceptibility of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus
2002Co-Authors: Justus Liebig, Jagdish Kumar, Ralph Huckelhoven, Lorant Kiraly, Karlheinz KogelAbstract:The barley resistance gene mlo5 determines race non-specific resistance to the biotrophic powdery mildew pathogen Blumeria graminis f.sp. hordei. On the other hand, we have shown that barley lines that contain the mlo5 gene display enhanced susceptibility to the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus) and its toxic culture filtrate (Kumar et al. 2001). Enhanced susceptibility to necrotic disease symptoms was linked to increased accumulation of hydrogen peroxide (H2O2), a reactive oxygen intermediate. In addition, increased accumulation of transcripts of a barley pathogenesis-related gene (PR1- b) and slight increases in expression of two antioxidant genes, a glutathione S transferase and an ascorbate peroxidase occurred in association with enhanced cell/tissue death and H2O2 accumulation. These results might reflect an unsuccessful attempt by infected mlo5-barley to suppress necrotic disease symptoms and support the hypothesis that the barley Mlo gene product functions as a negative regulator of cell death. Therefore, a compromised Mlo pathway confers effective control of the biotrophic powdery mildew pathogen but not of the necrotroph B. sorokiniana, demonstrating the necessity of different host defense strategies in response to pathogens with different lifestyles (biotroph vs. necrotroph).
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a compromised mlo pathway affects the response of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus and its toxins
Phytopathology, 2001Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Ulrich Beckhove, Subrahmaniam Nagarajan, Karlheinz KogelAbstract:ABSTRACT In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, ...
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a compromised mlo pathway affects the response of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus and its toxins
Phytopathology, 2001Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Ulrich Beckhove, Subrahmaniam Nagarajan, Karlheinz KogelAbstract:ABSTRACT In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, were also more sensitive to Bipolaris sorokiniana toxins than wild-type barley but showed less symptoms than mlo5 parents. Fungal culture filtrates induced an H2O2 burst in all mutants, whereas wild-type (Mlo) barley was less sensitive. The results support the hypothesis that the barley Mlo gene product functions as a suppresser of cell death. Therefore, a compromised Mlo pathway is effective for control of biotrophic powdery mildew fungus but not for necrotrophic Bipolaris sorokiniana. We discuss the problem of finding resistance traits that are effective against both biotrophic and necrotrophic pathogens with emphasis on the role of the anti-oxidative system of plant cells.
Ralph Huckelhoven - One of the best experts on this subject based on the ideXlab platform.
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the white barley mutant albostrians shows a supersusceptible but symptomless interaction phenotype with the hemibiotrophic fungus Bipolaris sorokiniana
Molecular Plant-microbe Interactions, 2004Co-Authors: Patrick Schafer, Ralph Huckelhoven, Karlheinz KogelAbstract:Bipolaris sorokiniana (teleomorph: Cochliobolus sativus) is a cereal pathogen of increasing global concern, with most significance in Asiatic cropping systems. In order to gain insight into the mechanism of host resistance, we studied fungal development on the supersusceptible barley mutant albostrians and its parent cv. Haisa. A microscopic dissection of early fungal growth on Haisa and green albostrians leaves revealed a distinct epidermis-localized biotrophic and a mesophyll-based necrotrophic phase. White, green, and striped white-green albostrians leaves showed extreme differences in disease development. When comparing cellular defense responses, we found restriction of fungal spreading after successful infection of host mesophyll tissue to be the most important mecha nism limiting outbreak of the disease. Colonization of susceptible green leaves, but not extreme colonization of supersusceptible white albostrians leaves, was associated with macroscopically visible lesion formation and mesophyll accum...
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Bipolaris sorokiniana a cereal pathogen of global concern cytological and molecular approaches towards better control
Molecular Plant Pathology, 2002Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Patrick Schafer, Gregor Langen, Helmut Baltruschat, Elke Stein, Subramaniam Nagarajan, Karlheinz KogelAbstract:Summary Bipolaris sorokiniana (teleomorph Cochliobolus sativus ) is the causal agent of common root rot, leaf spot disease, seedling blight, head blight, and black point of wheat and barley. The fungus is one of the most serious foliar disease constraints for both crops in warmer growing areas and causes significant yield losses. High temperature and high relative humidity favour the outbreak of the disease, in particular in South Asia's intensive ‘irrigated wheat–rice’ production systems. In this article, we review the taxonomy and worldwide distribution, as well as strategies to counteract the disease as an emerging threat to cereal production systems. We also review the current understanding of the cytological and molecular aspects of the interaction of the fungus with its cereal hosts, which makes B. sorokiniana a model organism for studying plant defence responses to hemibiotrophic pathogens. The contrasting roles of cell death and H 2O2 generation in plant defence during biotrophic and necrotrophic fungal growth phases are discussed.
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mlo5 a resistance gene effective against a biotrophic pathogen blumeria graminis fsp hordei confers enhanced susceptibility of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus
2002Co-Authors: Justus Liebig, Jagdish Kumar, Ralph Huckelhoven, Lorant Kiraly, Karlheinz KogelAbstract:The barley resistance gene mlo5 determines race non-specific resistance to the biotrophic powdery mildew pathogen Blumeria graminis f.sp. hordei. On the other hand, we have shown that barley lines that contain the mlo5 gene display enhanced susceptibility to the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus) and its toxic culture filtrate (Kumar et al. 2001). Enhanced susceptibility to necrotic disease symptoms was linked to increased accumulation of hydrogen peroxide (H2O2), a reactive oxygen intermediate. In addition, increased accumulation of transcripts of a barley pathogenesis-related gene (PR1- b) and slight increases in expression of two antioxidant genes, a glutathione S transferase and an ascorbate peroxidase occurred in association with enhanced cell/tissue death and H2O2 accumulation. These results might reflect an unsuccessful attempt by infected mlo5-barley to suppress necrotic disease symptoms and support the hypothesis that the barley Mlo gene product functions as a negative regulator of cell death. Therefore, a compromised Mlo pathway confers effective control of the biotrophic powdery mildew pathogen but not of the necrotroph B. sorokiniana, demonstrating the necessity of different host defense strategies in response to pathogens with different lifestyles (biotroph vs. necrotroph).
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a compromised mlo pathway affects the response of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus and its toxins
Phytopathology, 2001Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Ulrich Beckhove, Subrahmaniam Nagarajan, Karlheinz KogelAbstract:ABSTRACT In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, ...
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a compromised mlo pathway affects the response of barley to the necrotrophic fungus Bipolaris sorokiniana teleomorph cochliobolus sativus and its toxins
Phytopathology, 2001Co-Authors: Jagdish Kumar, Ralph Huckelhoven, Ulrich Beckhove, Subrahmaniam Nagarajan, Karlheinz KogelAbstract:ABSTRACT In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, were also more sensitive to Bipolaris sorokiniana toxins than wild-type barley but showed less symptoms than mlo5 parents. Fungal culture filtrates induced an H2O2 burst in all mutants, whereas wild-type (Mlo) barley was less sensitive. The results support the hypothesis that the barley Mlo gene product functions as a suppresser of cell death. Therefore, a compromised Mlo pathway is effective for control of biotrophic powdery mildew fungus but not for necrotrophic Bipolaris sorokiniana. We discuss the problem of finding resistance traits that are effective against both biotrophic and necrotrophic pathogens with emphasis on the role of the anti-oxidative system of plant cells.
Michael J Christensen - One of the best experts on this subject based on the ideXlab platform.
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an arbuscular mycorrhizal fungus and epichloe festucae var lolii reduce Bipolaris sorokiniana disease incidence and improve perennial ryegrass growth
Mycorrhiza, 2018Co-Authors: Fang Li, Michael J Christensen, Yanzhong Li, Tingyu DuanAbstract:Leaf spot of perennial ryegrass (Lolium perenne) caused by Bipolaris sorokiniana is an important disease in temperate regions of the world. We designed this experiment to test for the combined effects of the arbuscular mycorrhizal (AM) fungus Claroideoglomus etunicatum and the grass endophyte fungus Epichloe festucae var. lolii on growth and disease occurrence in perennial ryegrass. The results show that C. etunicatum increased plant P uptake and total dry weight and that this beneficial effect was slightly enhanced when in association with the grass endophyte. The presence in plants of both the endophyte and B. sorokiniana decreased AM fungal colonization. Plants inoculated with B. sorokiniana showed the typical leaf spot symptoms 2 weeks after inoculation and the lowest disease incidence was with plants that were host to both C. etunicatum and E. festucae var. lolii. Plants with these two fungi had much higher activity of peroxidases (POD), superoxide dismutase (SOD) and catalase (CAT) and lower values of malondialdehyde (MDA) and hydrogen peroxide (H2O2). The AM fungus C. etunicatum and the grass endophyte fungus E. festucae var. lolii have the potential to promote perennial ryegrass growth and resistance to B. sorokiniana leaf spot.
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an arbuscular mycorrhizal fungus and epichloe festucae var lolii reduce Bipolaris sorokiniana disease incidence and improve perennial ryegrass growth
Mycorrhiza, 2018Co-Authors: Yane Guo, Michael J Christensen, Ping Gao, Tingyu DuanAbstract:Leaf spot of perennial ryegrass (Lolium perenne) caused by Bipolaris sorokiniana is an important disease in temperate regions of the world. We designed this experiment to test for the combined effects of the arbuscular mycorrhizal (AM) fungus Claroideoglomus etunicatum and the grass endophyte fungus Epichloe festucae var. lolii on growth and disease occurrence in perennial ryegrass. The results show that C. etunicatum increased plant P uptake and total dry weight and that this beneficial effect was slightly enhanced when in association with the grass endophyte. The presence in plants of both the endophyte and B. sorokiniana decreased AM fungal colonization. Plants inoculated with B. sorokiniana showed the typical leaf spot symptoms 2 weeks after inoculation and the lowest disease incidence was with plants that were host to both C. etunicatum and E. festucae var. lolii. Plants with these two fungi had much higher activity of peroxidases (POD), superoxide dismutase (SOD) and catalase (CAT) and lower values of malondialdehyde (MDA) and hydrogen peroxide (H2O2). The AM fungus C. etunicatum and the grass endophyte fungus E. festucae var. lolii have the potential to promote perennial ryegrass growth and resistance to B. sorokiniana leaf spot.