Antifungal plant defensins: Insights into modes of action and prospects for engineering disease-resistant plants

Abstract

Defensins are small, cysteine-rich peptides that are ubiquitously present in all plants. They are important components of the plant immune system and serve as first line of defense against invading pathogens. Plant defensins share conserved tetradisulfide connectivity but vary in their sequence, net charge, and hydrophobicity. A number of plant defensins with potent broad-spectrum antifungal activity have been identified and characterized. Studies conducted during the past decade have highlighted the diverse modes of action (MOA) of a few antifungal defensins. Constitutive expression of these defensins has been demonstrated to confer in planta resistance to several economically important fungal and oomycete pathogens in transgenic crops. Here, we provide a brief review of recent findings that have contributed to our current understanding of the MOA of these peptides and their deployment for disease resistance in crops.