Recombinant Snakin-1 (SN1r) antifungal activity in vitro involves membrane permeabilization.

MUÑOZ F*;; ALMASIA, NI; PAGANO M,; HOPP, HE; DALEO G,; VAZQUEZ- ROVERE, C; GUEVARA M*

Cordoba

Congreso; XLIV Reunion Anual SAIB; 2008

SAIB

Snakin1 (SN1) is a cysteine-rich peptide isolated from potato tubers with a MW of 6,922 kDa. Previous reports show that SN1 has antimicrobial activity on fungal and bacterial plant pathogens. This protein is able to induce liposome aggregation but it is unable to leakage liposome composed by PC: PG phospholipids. In order to analyze in depth the antimicrobial mechanism of action of SN1, we have successfully subcloned the SN1 cDNA into pQE70 vector, expressed into M15 cells, induced with 1mM IPTG after 2 h. and purified in a Ni-agarose column. Recombinant SN1 (StSN1r) was able to inhibit F. solani spores germination and hyphae growth at the same concentrations reported to SN1wt in vitro (<10 ìM) in a dose dependent manner. When F. solani hyphae and spores were incubated with different concentrations of StSN1r, membrane permeabilization of these microbial structures was observed, as shown by the uptake of the fluorescent dye SYTOX Green. These results shown that, as well as the reported to others plants antimicrobial cysteine-rich peptide, citotoxic activity of StSN1 involves plasma membrane permeabilization.