Defensins are a superfamily of antimicrobial peptides, present in vertebrates, invertebrates,
fungi and plants, suggesting that they appeared prior to the divergence in eukaryotes. The destitution
of toxicity to mammalian cells of plant defensins has led to a new research ground, i.e., their potential
medical use against human infectious diseases. Isolating defensins from natural sources, like plant tissues,
can be time-consuming, labor intensive and usually present low yields. Strategies for large-scale
production of purified active defensins have been employed using heterologous expression systems
(HES) for defensin production, usually based in E. coli system. Like any other technology, HES present
limitations and drawbacks demanding a careful experimental design prior the system selection.
This review is proposed to discuss some of the major concerns when choosing to heterologously express
plant defensins, with special attention on bacterial expression systems.