RANDOM PEPTIDE MIXTURES AS NEW CROP PROTECTION AGENTS

Bacteria are among the most important causal agents of plant diseases. Almost all major crops are severely affected by one or more important bacterial diseases, which might cause significant food losses. The chemical control of bacterial plant diseases in the field mostly relies on copper-based bactericides, which possess limited efficacy. In addition, copper-resistant strains often emerge after their continuous application.

Host defense peptides (HDPs) have emerged as potential candidates to tackle the antibiotic resistance crisis. However, these type of peptides present two major disadvantages: the ability of bacteria to develop resistance towards them, and their high cost. Recently, the concept of Random Peptide Mixtures (RPMs) has been introduced with a modification of the conventional Fmoc-based solid-phase synthesis method. It was previously shown that RPMs of hydrophobic and cationic amino acids, such as ^Lphenylalanine-^L/Dlysine (FK and FdK, respectively) displays strong antimicrobial activity¹.

We explored the potential of these two RPMs as crop protection agents. We screened their ability to inhibit the growth as well as their bactericidal activity on several important plant-pathogenic bacteria. The RPMs were also tested for their ability to reduce disease severity of tomato and kohlrabi plants infected with Xanthomonas perforans and Xanthomonas campestris pv. campestris, respectively. Our findings support that the FK and FdK RPMs possess strong antimicrobial activity towards plant pathogenic bacteria and have the potential to be exploited as novel crop protection agents.

1. Hayouka, Z.; Chakraborty, S.; Liu, R.; Boersma, M. D.; Weisblum, B.;Gellman, S. H. J Am Chem Soc 2013.2