A comparative analysis of the heterotrimeric G-protein Gα, Gβ and Gγ subunits in the wheat pathogen Stagonospora nodorum
Date
2012
Authors
Gummer, Joel
Trengove, Robert D.
Oliver, Richard P.
Solomon, Peter
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Publisher
BioMed Central Ltd.
Abstract
Background: It has been well established that the G subunit of the heterotrimeric G-protein in the wheat pathogen Stagonospora nodorum is required for a variety of phenotypes including pathogenicity, melanisation and asexual differentiation. The roles though of the G and G subunits though were unclear. The objective of this study was to identify and understand the role of these subunits and assess their requirement for pathogenicity and development. Results: G-protein G and G subunits, named Gga1 and Gba1 respectively, were identified in the Stagonospora nodorum genome by comparative analysis with known fungal orthologues. A reverse genetics technique was used to study the role of these and revealed that the mutant strains displayed altered in vitro growth including a differential response to a variety of exogenous carbon sources. Pathogenicity assays showed that Stagonospora nodorum strains lacking Gba1 were essentially non-pathogenic whilst Gga1-impaired strains displayed significantly slower growth in planta. Subsequent sporulation assays showed that like the previously described G subunit mutants, both Gba1 and Gga1 were required for asexual sporulation with neither mutant strain being able to differentiate either pycnidia nor pycnidiospores under normal growth conditions. Continued incubation at 4°C was found to complement the mutation in each of the G-protein subunits with nearly wild-type levels of pycnidia recovered. Conclusion: This study provides further evidence on the significance of cAMP-dependent signal transduction for many aspects of fungal development and pathogenicity. The observation that cold temperatures can complement the G-protein sporulation defect now provides an ideal tool by which asexual differentiation can now be dissected.
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Keywords
Keywords: Gba1 protein; Gga1 protein; guanine nucleotide binding protein beta subunit; guanine nucleotide binding protein gamma subunit; unclassified drug; article; fungal virulence; fungus; genetic procedures; in vitro study; nonhuman; phenotype; plant disease; sp Asexual sporulation; cAMP-independent signal transduction; Fungal wheat pathogen; G-protein
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Source
BMC Microbiology
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Journal article
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Open Access
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