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 28.5 kDa and 68-98% sequence identity to other fungal 1,3,8-THN reductases. Targeted disruption of the THR1 gene showed that it is essential for melanin biosynthesis in B. oryzae. Northern blot analysis showed that THR1 transcripts are constitutively expressed during normal growth but are specifically enhanced by near-ultraviolet (NUV) radiation in a dose-dependent manner. These results indicate that THR1 expression is transcriptionally enhanced by NUV radiation 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
Ito
Machiko
M
Arase
Sakae
S
Honda
Yuichi
Y
D001203:Ascomycota / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D001483:Base Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal / Q000528:radiation effects; D005822:Genetic Vectors; D008543:Melanins / Q000096:biosynthesis / Q000528:radiation effects; D008969:Molecular Sequence Data; D015394:Molecular Structure; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014466:Ultraviolet Rays
D005656:Fungal Proteins; D008543:Melanins; C086024:tetrahydroxynaphthalene reductase; D044925:Oxidoreductases Acting on CH-CH Group Donors