In the universe of extant antimicrobial molecules, antimicrobial peptides (AMPs) hold great promise to protect crop plants, farm animals, and even humans against pathogens and insects (Lei et al., 2019). Unlike the existing armamentarium of antimicrobial drugs, one interesting feature of AMPs is their nonspecific mode of action, which is to destabilize the membrane of microbial pathogens. This results in considerably less development of bacterial resistance than seen with conventional antibiotics (Lei et al., 2019; Mwangi et al., 2019).

AMPs are peptides chains composed of 6 to 50 amino acid residues (Srivastava et al., 2021) expressed by almost all living organisms as part of their innate immune system (Nguyen et al., 2011; Zasloff, 2002, Zasloff, 2006). In eukaryotic cells, they are either constitutively expressed or induced upon abiotic and abiotic stresses (Nawrot et al., 2014). The prevalence of cationic amino acid residues such as lysine and arginine over the acidic ones make AMPs have positive net charged (+2 to +12), enabling more effective electrostatic interactions with negatively charged membrane components (Da Costa et al., 2015; Sani and Separovic, 2016). As of December 2023, around 21,367 AMPs have been characterized, including 1923 AMPs from plants (https://dbaasp.org/home).

Purothionin, which is found in the endosperm of wheat kernels, was the first plant-derived AMP isolated and characterized (Balls et al., 1942). Since then, hundreds of AMPs belonging to different classes have been isolated from plant organs and species (Table 1). Similar to other AMPs classes, plant peptides have been also classified based on their amino acids sequence, number of disulfide bridges, mechanism of action (Lay and Anderson, 2005), and net charge (Barbosa Pelegrini et al., 2011). In addition to their antimicrobial activities, some plant AMPs have been shown to regulate plant growth and development (Li et al., 2021). Although a number of plant-derived AMPs have been proposed as potential alternatives to conventional antibiotics, none are currently used in clinical practice to treat fungal or bacterial infections (Porto et al., 2018; Divyashree et al., 2020), partly because most plant encoding AMPs undergo post-translational modifications, so often to achieve a therapeutic effect, a high dose is needed.