The function and properties of the transcriptional regulator COS1 in Magnaporthe oryzae

The conidiophore stalk-less1 (COS1) gene encodes a novel transcription factor in Magnaporthe oryzae, and mutation of COS1 (M2942) resulted in developmental failure of conidiophores. COS1 putatively encodes a 491-amino-acid protein, which contains four multiple adjacent C2H2-type zinc-finger domains. The motifs are homologous to the zinc-finger protein Azf1 of Saccharomyces cerevisiae. Here, we report that the differences of expression profile between M2942 and the wild-type isolate Y34 by RNA-Sequence. DNA sequence analysis of promoter regions of those of COS1-dependent genes showed enrichment in the DNA sequence AAAAGAAA (A4GA3), the putative COS1-binding motif. Gel shift experiments showed that COS1 binds to DNA elements with A4GA3 motif. These suggest that many of the COS1-dependent transcripts may be regulated directly by COS1 binding.