Pathogenicity of Stagonospora nodorum requires malate synthase

A gene encoding malate synthase, a key enzyme of the glyoxylate cycle, has been cloned and characterized in the necrotrophic wheat pathogen Stagonospora nodorum. Expression studies of Mls1 showed high levels of transcript in ungerminated spores whereas malate synthase enzyme activities were low. Exp...

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Main Authors: Solomon, P., Lee, Robert, Wilson, T., Oliver, Richard
Format: Journal Article
Published: 2004
Online Access:http://hdl.handle.net/20.500.11937/46081
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author Solomon, P.
Lee, Robert
Wilson, T.
Oliver, Richard
author_facet Solomon, P.
Lee, Robert
Wilson, T.
Oliver, Richard
author_sort Solomon, P.
building Curtin Institutional Repository
collection Online Access
description A gene encoding malate synthase, a key enzyme of the glyoxylate cycle, has been cloned and characterized in the necrotrophic wheat pathogen Stagonospora nodorum. Expression studies of Mls1 showed high levels of transcript in ungerminated spores whereas malate synthase enzyme activities were low. Expression studies in planta found that Mls1 transcript levels decreased ≈ 10-fold upon germination before slowly increasing throughout the remainder of the infection. To characterize Mls1 further, the gene was disrupted in S. nodorum by homologous recombination. In the absence of any supplied carbon source, the mls1 spores were unable to germinate and consequently the mutants were non-pathogenic. Germination and pathogenicity could be restored by the addition of either glucose or sucrose, implying that S. nodorum is reliant upon the catabolism of lipids for infection. Furthermore, analysis of lipid bodies in the mutant strain indicated that lipid mobilization and, consequently, peroxisomal β-oxidation of fatty acids is delayed or inhibited by the disruption of the glyoxylate cycle. This study has demonstrated for the first time in a fungal phytopathogen the requirement of malate synthase for pathogenicity, suggesting that gluconeogenesis is both dependent on the glyoxylate cycle and required for infection.
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spelling curtin-20.500.11937-460812020-08-21T03:23:24Z Pathogenicity of Stagonospora nodorum requires malate synthase Solomon, P. Lee, Robert Wilson, T. Oliver, Richard A gene encoding malate synthase, a key enzyme of the glyoxylate cycle, has been cloned and characterized in the necrotrophic wheat pathogen Stagonospora nodorum. Expression studies of Mls1 showed high levels of transcript in ungerminated spores whereas malate synthase enzyme activities were low. Expression studies in planta found that Mls1 transcript levels decreased ≈ 10-fold upon germination before slowly increasing throughout the remainder of the infection. To characterize Mls1 further, the gene was disrupted in S. nodorum by homologous recombination. In the absence of any supplied carbon source, the mls1 spores were unable to germinate and consequently the mutants were non-pathogenic. Germination and pathogenicity could be restored by the addition of either glucose or sucrose, implying that S. nodorum is reliant upon the catabolism of lipids for infection. Furthermore, analysis of lipid bodies in the mutant strain indicated that lipid mobilization and, consequently, peroxisomal β-oxidation of fatty acids is delayed or inhibited by the disruption of the glyoxylate cycle. This study has demonstrated for the first time in a fungal phytopathogen the requirement of malate synthase for pathogenicity, suggesting that gluconeogenesis is both dependent on the glyoxylate cycle and required for infection. 2004 Journal Article http://hdl.handle.net/20.500.11937/46081 10.1111/j.1365-2958.2004.04178.x restricted
spellingShingle Solomon, P.
Lee, Robert
Wilson, T.
Oliver, Richard
Pathogenicity of Stagonospora nodorum requires malate synthase
title Pathogenicity of Stagonospora nodorum requires malate synthase
title_full Pathogenicity of Stagonospora nodorum requires malate synthase
title_fullStr Pathogenicity of Stagonospora nodorum requires malate synthase
title_full_unstemmed Pathogenicity of Stagonospora nodorum requires malate synthase
title_short Pathogenicity of Stagonospora nodorum requires malate synthase
title_sort pathogenicity of stagonospora nodorum requires malate synthase
url http://hdl.handle.net/20.500.11937/46081