Cloning, Characterization, and Bacterial Over-Expression of an Osmotin-like Protein Gene from Solanum nigrum L. with Antifungal Activity Against Three Necrotrophic Fungi

• DOI: 10.1007/s12033-014-9831-4
• Publication Date: 2015-01-07T23:40:31Z
• Authors: Supriyo Chowdhury; Arpita Basu; Surekha Kundu
• Keywords: 0303 health sciences; Antifungal Agents; Protein Stability; Cell Membrane; Fungi; Microbial Sensitivity Tests; Hydrogen-Ion Concentration; Recombinant Proteins; 3. Good health; 03 medical and health sciences; Escherichia coli; Cloning, Molecular; Plant Proteins; Solanum nigrum

A new osmotin-like protein gene from Solanum nigrum L. var indica (SindOLP) was cloned and overexpressed in Escherichia coli. The full-length intron-less gene is 744 bp, encoding a mature protein of 247 amino acids with a molecular mass of 26 kDa. The protein has an N-terminal cleavable signal sequence of 21 amino acids. There is the Thaumatin family signature pattern, with one each of amidation, N-myristoylation, casein kinase II phosphorylation, tyrosine kinase phosphorylation, and protein kinase C phosphorylation sites. Hydropathy plot showed that it has six transmembrane helices. It has antifungal activity and can permeabilize fungal hyphae and spores. SindOLP is most active at pH 8, 25 °C and its antifungal activity is retained after 75 °C for 30 min. SindOLP inhibits fungal spore germination. The protein however lacks glucanase activity. The potential for SindOLP in developing fungus-resistant, transgenic crops is discussed.