Functional redundancy in Echinocandin B in-cluster transcription factor ecdB of Emericella rugulosa NRRL 11440

Echinocandin B is a potent antifungal against the majority of fungal pathogens and its biosynthesis occurred by ecd and hty gene clusters in Emericella rugulosa NRRL 11440. We elucidated the functional necessity of in-clustered transcription factor; ecdB in the production of echinocandin B. We deleted the ecdB gene and found that ΔecdB mutant has no significant effect on echinocandin B production. The expression level of most of the ecd and hty cluster genes was not significantly altered except few of them up-regulated in knockout strain. The complete abrogation in ecdB gene expression was observed in ΔecdB strain. However, the interactions of purified EcdB protein with DNA sequence of ecdA, ecdH, ecdK and ecdI promoter was confirmed in-vitro. Our results conclude that EcdB protein in-vitro binds to the ecdA, ecdH, ecdK and ecdI promoter but in-vivo, it could not significantly affect the gene expression and echinocandin B production in Emericella rugulosa.