Transgenic plants expressing cationic peptide chimeras exhibit broad-spectrum resistance to phytopathogens

Abstract

Here we describe a strategy for engineering transgenic plants with broad-spectrum resistance to bacterial and fungal phytopathogens. We expressed a synthetic gene encoding a N terminus-modified, cecropin-melittin cationic peptide chimera (MsrA1), with broad-spectrum antimicrobial activity. The synthetic gene was introduced into two potato (Solanum tuberosum L.) cultivars, Desiree and Russet Burbank, stable incorporation was confirmed by PCR and DNA sequencing, and expression confirmed by reverse transcription (RT)-PCR and recovery of the biologically active peptide. The morphology and yield of transgenic Desiree plants and tubers was unaffected. Highly stringent challenges with bacterial or fungal phytopathogens demonstrated powerful resistance. Tubers retained their resistance to infectious challenge for more than a year, and did not appear to be harmful when fed to mice. Expression of msrA1 in the cultivar Russet Burbank caused a striking lesion-mimic phenotype during leaf and tuber development, indicating its utility may be cultivar specific. Given the ubiquity of antimicrobial cationic peptides as well as their inherent capacity for recombinant and combinatorial variants, this approach may potentially be used to engineer a range of disease-resistant plants.

An amphibian antimicrobial peptide variant expressed in Nicotiana tabacum confers resistance to phytopathogens

“…Hybrid peptides retaining the ability to kill bacteria without harming plant cells were also investigated. Plants expressing a cecropin-melittin cationic chimaera showed resistance to bacteria as well as fungi [7], although the efficacy of the chimaera was cultivar-specific.…”

“…Advances in genetic engineering have made possible the development of plants with new predictable phenotypes [1,2]. In particular, to increase resistance against diseases, different genetic strategies have been proposed, which include utilization of antibacterial proteins of both plant [3][4][5] and non-plant origin [6,7].…”

Genome Editing with Engineered Nucleases in Economically Important Animals and Plants: State of the Art in the Research Pipeline

“…Several resistant varieties have been successfully developed using transgenesis, such as the ringspot virus-resistant papaya (Fitch et al, 1992) or the fungusresistant Innate™ Russet Burbank Potato (Osusky et al, 2000). The cultivation of diseaseresistant plants has the potential to reduce the " 44…”

Antimicrobial peptides

“…Undesirably, application of AMPs to engineer pathogen resistance in plants suffers from some limitations, namely species-and race-specificity of the peptides, 120 slight enhanced resistance, 106 induction of infertility, 121 and leakage of conferred resistance after a while due to resiliency of disease-causing microbes. 38 To alleviate these drawbacks as well as to increase the antimicrobial potency of existing peptides, several approaches have been proposed to follow.…”

“…120,123,124 Expression of antibody-AMP fusion proteins has been shown to control microbial pathogens, more efficiently and durably. 125,126 Also, targeting the AMPs into endoplasmic reticulum instead of intercellular spaces dramatically drops the probability of infertility.…”