Functional redundancy in Echinocandin B in-cluster transcription factor ecd B 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; ecd B in the production of echinocandin B. We deleted the ecd B gene and found that Δ ecd B 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 ecd B gene expression was observed in Δ ecd B strain. However, the interactions of purified EcdB protein with DNA sequence of ecd A, ecd H, ecd K and ecd I promoter was confirmed in-vitro . Our results conclude that EcdB protein in-vitro binds to the ecd A, ecd H, ecd K and ecd I promoter but in-vivo , it could not significantly affect the gene expression and echinocandin B production in Emericella rugulosa.