Tejesvi MV, Andersen B, Antcheva N, Brinch KS, Koskimaki JJ, Kristensen HH, Tossi A and Pirttila AM
Endophytes induce plant growth and protect host plants against abiotic and biotic stresses, such as phytopathogenic bacteria and fungi. Here we explored the genome of plant growth-promoting, intracellular endophyte Methylobacterium extorquens DSM13060, isolated from bud meristems of Pinus sylvestris L., for antimicrobial peptides. A defensin-like antimicrobial peptide MB1533 was identified using computational and prediction models from the genome sequence. MB1533 was produced in Escherichia coli with a molecular weight of 6160.26 Da. The antimicrobial activity was tested against several strains of bacteria and yeasts, and the peptide had activity against the gram-positive Staphylococcus aureus and Bacillus subtilis at 128 μg/ml. The potency of the peptide can be improved further by rational-design-techniques. MB1533 is the first defensin-like peptide identified from Methylobacterium genus and from bacterial endophytes, in general.