Challenges of using protein antibiotics for pathogen control.

Bacterial phytopathogens represent a significant threat to many economically important crops. Current control measures often inflict harm on the environment and may ultimately impact on human health through the spread of antibiotic resistance. Antimicrobial proteins such as bacteriocins have been suggested as the next generation of disease control agents since they are able to specifically target the pathogen of interest with minimal impact on the wider microbial community and environment. However, substantial gaps in knowledge with regards to the efficacy and application of bacteriocins to combat phytopathogenic bacteria remain. Here we highlight the immediate challenges the community must address to ensure maximum exploitation of antimicrobial proteins in the field. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Bacteriocins Targeting Gram-Negative Phytopathogenic Bacteria: Plantibiotics of the Future.

Gram-negative phytopathogenic bacteria are a significant threat to food crops. These microbial invaders are responsible for a plethora of plant diseases and can be responsible for devastating losses in crops such as tomatoes, peppers, potatoes, olives, and rice. Current disease management strategies to mitigate yield losses involve the application of chemicals which are often harmful to both human health and the environment. Bacteriocins are small proteinaceous antibiotics produced by bacteria to kill closely related bacteria and thereby establish dominance within a niche. They potentially represent a safer alternative to chemicals when used in the field. Bacteriocins typically show a high degree of selectivity toward their targets with no off-target effects. This review outlines the current state of research on bacteriocins active against Gram-negative phytopathogenic bacteria. Furthermore, we will examine the feasibility of weaponizing bacteriocins for use as a treatment for bacterial plant diseases.

Engineering bacteriocin-mediated resistance against the plant pathogen Pseudomonas syringae.

The plant pathogen, Pseudomonas syringae (Ps), together with related Ps species, infects and attacks a wide range of agronomically important crops, including tomato, kiwifruit, pepper, olive and soybean, causing economic losses. Currently, chemicals and introduced resistance genes are used to protect plants against these pathogens but have limited success and may have adverse environmental impacts. Consequently, there is a pressing need to develop alternative strategies to combat bacterial disease in crops. One such strategy involves using narrow-spectrum protein antibiotics (so-called bacteriocins), which diverse bacteria use to compete against closely related species. Here, we demonstrate that one bacteriocin, putidacin L1 (PL1), can be expressed in an active form at high levels in Arabidopsis and in Nicotiana benthamiana in planta to provide effective resistance against diverse pathovars of Ps. Furthermore, we find that Ps strains that mutate to acquire tolerance to PL1 lose their O-antigen, exhibit reduced motility and still cannot induce disease symptoms in PL1-transgenic Arabidopsis. Our results provide proof-of-principle that the transgene-mediated expression of a bacteriocin in planta can provide effective disease resistance to bacterial pathogens. Thus, the expression of bacteriocins in crops might offer an effective strategy for managing bacterial disease, in the same way that the genetic modification of crops to express insecticidal proteins has proven to be an extremely successful strategy for pest management. Crucially, nearly all genera of bacteria, including many plant pathogenic species, produce bacteriocins, providing an extensive source of these antimicrobial agents.

Draft Genome Sequence of the Necrotrophic Plant-Pathogenic Bacterium Pectobacterium carotovorum subsp. carotovorum Strain LMG 2410.

Here, we report the draft genome sequence of Pectobacterium carotovorum subsp. carotovorum strain LMG 2410, isolated from cucumber in the United Kingdom. The draft genome is 4,773,000 bp, with a G+C content of 51.9%, and carries a total of 4,536 coding sequences.