RESUMO
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. oryzae. Northern blot analysis showed that PKS1 transcripts were specifically enhanced by near-ultraviolet radiation (300-400 nm) and that its temporal transcriptional patterns were similar to those of THR1 and SCD1 genes involved in the melanin biosynthesis pathway of B. oryzae.
Assuntos
Ascomicetos/enzimologia , Genes Fúngicos , Melaninas/biossíntese , Policetídeo Sintases/genética , Policetídeo Sintases/metabolismo , Sequência de Aminoácidos , Ascomicetos/genética , Sequência Conservada , DNA Fúngico/química , DNA Fúngico/isolamento & purificação , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Dados de Sequência Molecular , Mutagênese Insercional , Fases de Leitura Aberta , Policetídeo Sintases/química , RNA Fúngico/biossíntese , RNA Mensageiro/biossíntese , Alinhamento de Sequência , Análise de Sequência de DNA , Transcrição Gênica , Raios UltravioletaRESUMO
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. Targeted disruption of SCD1 showed that this gene is necessary for melanin biosynthesis in B. oryzae. Northern blot analysis showed that SCD1 transcripts are specifically enhanced by near-ultraviolet (300-400 nm) radiation.
