Functions of the Magnaporthe oryzae Flb3p and Flb4p transcription factors in the regulation of conidiation.
The Magnaporthe oryzae genes FLB3 and FLB4, orthologues of the Aspergillus nidulans regulators of conidiation FlbC and FlbD, were inactivated. These genes encode C2H2 zinc finger and Myb-like transcription factors, respectively, in A. nidulans. Analysis of the resultant mutants demonstrated that FLB4 is essential for spore formation and that strains lacking this gene are fluffy in their colony morphology due to an inability to complete conidiophore formation. Meanwhile, FLB3 is required for normal levels of aerial mycelium formation. We identified genes dependent on both transcription factors using microarray analysis. This analysis revealed that the transcription of several genes encoding proteins implicated in sporulation in Magnaporthe oryzae and other filamentous fungi are affected by FLB3 or FLB4 inactivation. Furthermore, the microarray analysis indicates that Flb3p may effectively reprogramme the cell metabolically by repressing transcription of genes encoding biosynthetic enzymes and inducing transcription of genes encoding catabolic enzymes. Additionally, qRT-PCR was employed and showed that FLB3 and FLB4 transcripts are enriched in synchronously sporulating cultures, as were the transcripts of other genes that are necessary for normal conidiation, consistent with a role for their gene products in this process.
Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger-Str. 56, D-67663 Kaiserslautern, Germany.
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Matheis
Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger-Str. 56, D-67663 Kaiserslautern, Germany. Electronic address: yemelin@ibwf.de.
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Yemelin
Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger-Str. 56, D-67663 Kaiserslautern, Germany.
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Scheps
Institut für Mikrobiologie und Weinforschung, Johann-Joachim-Becherweg 15, D-55128 Mainz, Germany.
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Andresen
Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger-Str. 56, D-67663 Kaiserslautern, Germany.
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Jacob
Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger-Str. 56, D-67663 Kaiserslautern, Germany; Institut für Mikrobiologie und Weinforschung, Johann-Joachim-Becherweg 15, D-55128 Mainz, Germany.
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Thines
Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger-Str. 56, D-67663 Kaiserslautern, Germany. Electronic address: A.J.Foster@exeter.ac.uk.
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Foster
D015536:Down-Regulation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D020082:Magnaporthe / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008543:Melanins / Q000096:biosynthesis / Q000378:metabolism; D009024:Morphogenesis / Q000235:genetics / Q000502:physiology; D009154:Mutation; D025282:Mycelium / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D012331:RNA, Fungal / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015854:Up-Regulation
D005656:Fungal Proteins; D008543:Melanins; D012331:RNA, Fungal; D014157:Transcription Factors
Conidiation; Fluffy gene; Magnaporthe; Melanization; Metabolic reprogramming; Transcription factor