Pseudomonas protegens CS1 fromthe lemon phyllosphere as a candidate for citrus canker biocontrol agent

MICHAVILA, GABRIELA; ADLER, CONRADO; DE GREGORIO, PRISCILA; LAMI, MARÍA JESUS; CARAM DI SANTO, MARÍA CAROLINA; ZENOFF, ANA; DE CRISTOBAL, RICARDO EZEQUIEL; VINCENT, PAULA

PLANT BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017

1435-8603

Citrus canker is a worldwide-distributed disease caused by Xanthomonas citri subsp.citri. One of the most used strategies to control the disease is centred on copper-basedcompounds that cause environmental problems. Therefore, it is of interest to developnew strategies to manage the disease. Previously, we reported the ability of the siderophorepyochelin, produced by the opportunistic human pathogen Pseudomonas aeruginosa,to inhibit in vitro several bacterial species, including X. citri subsp. citri. Theaction mechanism, addressed with the model bacterium Escherichia coli, was connectedto the generation of reactive oxygen species (ROS). This work aimed to find anon-pathogenic strain from the lemon phyllosphere that would produce pyochelinand therefore serve in canker biocontrol.? An isolate that retained its capacity to colonise the lemon phyllosphere and inhibitX. citri subsp. citri was selected and characterised as Pseudomonas protegens CS1. Froma liquid culture of this strain, the active compound was purified and identified as thepyochelin enantiomer, enantio-pyochelin.? Using the producing strain and the pure compound, both in vitro and in vivo, wedetermined that the action mechanism of X. citri subsp. citri inhibition also involvedthe generation of ROS. Finally, the potential application of P. protegens CS1 was evaluatedby spraying the bacterium in a model that mimics the natural X. citri subsp. citriinfection.? The ability of P. protegens CS1 to reduce canker formation makes this strain an interestingcandidate as a biocontrol agent.