Cloning and expression analysis of two opsin-like genes in the phytopathogenic fungus Bipolaris oryzae.

Two opsin-like genes, OPS1 and OPS2, were identified from a subtracted cDNA library for the identification of near-UV (NUV) radiation-enhanced genes using suppression subtractive hybridization methods in the brown leaf spot fungus Bipolaris oryzae. The OPS1 and OPS2 genes encode predicted proteins of 306 and 304 amino acids, respectively. Real-time PCR analysis showed that the OPS1 transcript is expressed weakly in mycelia under dark conditions but shows enhanced expression after NUV irradiation.

Characterization of the BMR1 gene encoding a transcription factor for melanin biosynthesis genes in the phytopathogenic fungus Bipolaris oryzae.

We isolated and characterized Bipolaris melanin regulation 1 gene (BMR1) encoding a transcription factor for melanin biosynthesis genes in the phytopathogenic fungus Bipolaris oryzae. Sequence analysis showed that the BMR1 gene encodes a putative protein of 1012 amino acids that has 99% sequence similarity to transcription factor Cmr1 of Cochliobolus heterostrophus. The predicted B.

Cloning and characterization of the BLR2, the homologue of the blue-light regulator of Neurospora crassa WC-2, in the phytopathogenic fungus Bipolaris oryzae.

Bipolaris oryzae is a filamentous ascomycetous fungus that causes brown leaf spot disease in rice. We isolated and characterized BLR2, a gene that encodes a putative blue-light regulator similar to Neurospora crassa white collar-2 (WC-2). The deduced amino acid sequence of the BLR2 showed significant homology to other fungal blue-light regulator proteins in the Per-Arnt-Sim (PAS) protein-protein interaction domain, nuclear localization signal, and GATA zinc finger DNA-binding domains.

Characterization of the BLR1 gene encoding a putative blue-light regulator in the phytopathogenic fungus Bipolaris oryzae.

Bipolaris oryzae is a filamentous ascomycetous fungus that causes brown leaf spot disease in rice. We isolated and characterized BLR1, a gene that encodes a putative blue-light regulator similar to Neurospora crassa white-collar 1 (WC-1). The deduced amino acid sequence of BLR1 showed high degrees of similarity to other fungal blue-light regulator protein.

RNA-mediated gene silencing in the phytopathogenic fungus Bipolaris oryzae.

The Ascomycetous fungus Bipolaris oryzae is the causal agent of brown leaf spot disease in rice and is a model for studying photomorphogenetic responses by near-UV radiation. Targeted gene disruption (knockout) for functional analysis of photomorphogenesis-related genes in B. oryzae can be achieved by homologous recombination with low efficiency.

Disruption of SRM1, a mitogen-activated protein kinase gene, affects sensitivity to osmotic and ultraviolet stressors in the phytopathogenic fungus Bipolaris oryzae.

Mitogen-activated protein kinases (MAPKs) play key roles in biological processes including differentiation, growth, proliferation, survival, and stress responses. We isolated and characterized the SRM1 gene, which encodes an MAPK related to yeast High-osmolarity glycerol 1 (Hog1), from the rice leaf pathogen Bipolaris oryzae. The deduced amino sequence of the SRM1 gene showed significant homology with Hog1-type MAPK homologues from other phytopathogenic fungi and contained a TGY motif for phosphorylation.

A MAP kinase gene, BMK1, is required for conidiation and pathogenicity in the rice leaf spot pathogen Bipolaris oryzae.

We isolated and characterized BMK1, a gene encoding a mitogen-activated protein kinase (MAPK), from the rice leaf spot pathogen Bipolaris oryzae. The deduced amino acid sequence showed significant homology with Fus3/Kss1 MAPK homologues from other phytopathogenic fungi. The BMK1 disruptants showed impaired hyphal growth, no conidial production, and loss of virulence against rice leaves, indicating that the BMK1 is essential for conidiation and pathogenicity in B.

Insertional mutagenesis and characterization of a polyketide synthase gene (PKS1) required for melanin biosynthesis in Bipolaris oryzae.

A polyketide synthase gene named PKS1, involved in the melanin biosynthesis pathway of the phytopathogenic fungus Bipolaris oryzae, was isolated using restriction enzyme-mediated integration. Sequence analysis showed that the PKS1 encodes a putative protein that has 2155 amino acids and significant similarity to other fungal polyketide synthases. Targeted disruption of the PKS1 gene showed that it is necessary for melanin biosynthesis in B.

Cloning, functional characterization, and near-ultraviolet radiation-enhanced expression of a photolyase gene (PHR1) from the phytopathogenic fungus Bipolaris oryzae.

Photolyase is a DNA repair enzyme that can absorb blue/ultraviolet A light as energy and split a pyrimidine dimer induced by ultraviolet radiation. We isolated and characterized PHR1, a gene encoding photolyase, from the phytopathogenic fungus Bipolaris oryzae. Sequence analysis showed that PHR1 encodes a putative protein that has 634 amino acids, a molecular mass of 72.

Expression of THR1, a 1,3,8-trihydroxynaphthalene reductase gene involved in melanin biosynthesis in the phytopathogenic fungus Bipolaris oryzae, is enhanced by near-ultraviolet radiation.

1,3,8-Trihydroxynaphthalene (1,3,8-THN) reductase is involved in the production of fungal dihydroxynaphthalene (DHN) melanin. We isolated and characterized THR1, a gene encoding 1,3,8-THN reductase, from the phytopathogenic fungus Bipolaris oryzae. Sequence analysis showed that THR1 encodes a putative protein of 267 amino acids having a molecular weight of 28.

Cloning, functional analysis and expression of a scytalone dehydratase gene ( SCD1) involved in melanin biosynthesis of the phytopathogenic fungus Bipolaris oryzae.

Scytalone dehydratase is involved in the production of fungal dihydroxynaphthalene melanin. We isolated and characterized SCD1, a gene encoding scytalone dehydratase, from the phytopathogenic fungus Bipolaris oryzae. Sequence analysis showed that SCD1 encodes a putative protein that has 185 amino acids, a molecular weight of 21 kDa and 51-75% sequence identity to other fungal scytalone dehydratases.

Increased tryptophan decarboxylase and monoamine oxidase activities induce Sekiguchi lesion formation in rice infected with Magnaporthe grisea.

Sekiguchi lesion (sl)-mutant rice infected with Magnaporthe grisea showed increased light-dependent tryptophan decarboxylase (TDC) and monoamine oxidase (MAO) activities. TDC and MAO activities were observed before the penetration of M. grisea to rice cells and maintained high levels even after Sekiguchi lesion formation.