AUTHOR=Shcherbak Nataliia , Prochaska Heike , Lystvan Kateryna , Prokhorova Yelizaveta , Giritch Anatoli , Kuchuk Mykola 

TITLE=Accumulation of colicin M protein and its biological activity in transgenic lettuce and mizuna plants

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1271757

DOI=10.3389/fpls.2023.1271757

ISSN=1664-462X

ABSTRACT=<p>Food-borne illnesses caused by pathogenic <italic>Escherichia coli</italic> strains, especially enterohaemorrhagic <italic>E. coli</italic> (EHEC), are a serious public health problem, as debilitating disease and even death from such food poisonings have been repeatedly reported. Colicin M (ColM), a non-antibiotic antimicrobial protein produced by some strains of <italic>E. coli</italic>, has shown promising activity in controlling multiple enteropathogenic strains of <italic>E. coli</italic> and related pathogens. As contaminated green leafy vegetables are a frequent source of pathogenic <italic>E. coli</italic> infections, we genetically modified (GM) two edible crops, lettuce (<italic>Lactuca sativa</italic> L.) and mizuna (<italic>Brassica rapa</italic> subsp. nipposinica var. laciniata), to stably express the ColM gene and assessed the antibacterial activity of tissue extracts from these plants against selected <italic>E. coli</italic> strains <italic>in vitro</italic>. Transgenic plants of these species were developed using <italic>Agrobacterium</italic>-mediated transformation with a vector containing the ColM-coding gene (<italic>cma</italic>) under the control of the 35S promoter. Western blot analysis of recombinant ColM protein was performed in selected transgenic plants to confirm <italic>cma</italic> gene expression and quantify ColM accumulation. Extracts of transgenic plants expressing ColM showed significant activity against two major strains of EHEC (O157:H7 and O104:H4) as well as <italic>E. coli</italic> strains resistant to beta-lactam- and carbapenem-class antibiotics. Importantly, the antibacterial activity persisted in several subsequent generations of transgenic lettuce and mizuna plants that stably expressed the ColM gene. In addition, our results also show that the antibacterial activity of dried (up to 40°C) biomass of transgenic plants remained stable without a decrease for at least three months.</p>