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. By contrast, the OPS2 transcript is constitutively expressed at a high level in mycelia under dark conditions but is only weakly enhanced after NUV irradiation. These enhancement patterns of OPS1 and OPS2 gene expression after NUV irradiation did not occur in the blue-light regulator 1 (BLR1)-deficient mutant, suggesting that NUV radiation-enhanced gene expression of OPS1 and OPS2 could be controlled by the BLR1 in B. oryzae.