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. oryzae Bmr1 protein has two DNA-binding motifs, two Cys2His2 zinc finger domains, and a Zn(II)2Cys6 binuclear cluster domain at the N-terminal region of Bmr1. Targeted disruption of the BMR1 gene showed that BMR1 is essential for melanin biosynthesis in B. oryzae. The overexpression of the BMR1 gene led to more dark colonies than in the wild-type strain under dark conditions. Real-time PCR analysis showed that the BMR1 expression of the overexpression transformant was about 10-fold that of the wild type under dark conditions and of the expression of three melanin biosynthesis genes. These results indicated that BMR1 encodes the transcription factor of melanin biosynthesis genes in B. oryzae.
Kihara
Junichi
J
Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan. j-kihara@life.shimane-u.ac.jp
Moriwaki
Akihiro
A
Tanaka
Nozomi
N
Tanaka
Chihiro
C
Ueno
Makoto
M
Arase
Sakae
S
D000595:Amino Acid Sequence; D001203:Ascomycota / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D008543:Melanins / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D010944:Plants / Q000382:microbiology*; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000528:radiation effects; D014466:Ultraviolet Rays
D005656:Fungal Proteins; D008543:Melanins; D014157:Transcription Factors