Plant defensins—Prospects for the biological functions and biotechnological properties

Abstract

Plant defensins are a prominent family of cationic peptides in the plant kingdom. They are structurally and functionally related to defensins that have been previously characterized in mammals and insects. They present molecular masses between 5 and 7kDa and possess a pattern of eight conserved Cys residues. The three-dimensional structure of plant defensins is small and globular. It has three anti-parallel beta-sheets and one alpha-helix that is stabilized by a structural motif composed of disulfide bridges. This motif is found in other peptides with biological activity and is called the Cys stabilized alphabeta motif (CSalphabeta). Based on the growing knowledge on defensin structure, gene expression and regulation, and also their in vitro biological activity, it has become clear that plant defensins are complex and sophisticated peptides whose function extends beyond their role in defense of plants against microbial infection. This review discusses recent data and will present comprehensive information regarding the study of defensins.

Expression, purification and characterization of the recombinant cysteine-rich antimicrobial peptide snakin-1 in Pichia pastoris

“…Many AMPs are cysteine-stabilized and these have been classified into several families [14], including cyclotides [15], defensins [16], hevein-like peptides [17], lipid transfer proteins [18], and snakins [11,19]. The snakin family is a novel plant antimicrobial peptide family which shows good similarity with the members of the gibberellic acid stimulated transcript (GAST) and gibberellic acid stimulated in Arabidopsis (GASA) protein families in Arabidopsis [20].…”

PvD1 defensin, a plant antimicrobial peptide with inhibitory activity against Leishmania amazonensis

“…Plant defensins are capable of inhibiting the growth of a wide variety of filamentous fungi and yeast [5,6,23,22,26,27]. Despite the wide inhibitory activity that plant defensins have against different micro-organisms, there is a gap in our knowledge regarding the mechanism of action of plant defensins against protozoa.…”

“…This structure is stabilized by four disulfide bonds, which form a cysteine-stabilized α-helix β-strands motif, commonly found in these peptides [5,6]. The antimicrobial activity of plant defensins is mainly observed Figure 1 Inhibition of the proliferation of L. amazonensis promastigotes in the presence of PvD 1 Proliferation was observed for a 48 h period.…”

Nematode-derived drosomycin-type antifungal peptides provide evidence for plant-to-ecdysozoan horizontal transfer of a disease resistance gene

“…In plants and the ecdysozoans with this gene, most of DTAFPs also exist as multigene families and some have evolved novel biological functions. For example, in addition to major antifungal activity, some plant DTAFPs have developed diverse activities as inhibitors of protein translation, enzymes and bacterial growth, mediators of zinc tolerance, and blockers of ion channels 44 . Similarly, drosomycin has been found to gain ability in interacting with the fly voltage-gated sodium channel, possibly acting as a neuropeptide 25 .…”