Heterologous expression of CECMEL11 bactericidal peptides against Xylella fastidiosa in Nicotiana benthamiana plants

Xylella fastidiosa (Xf) diseases have emerged in recent years as several outbreaks of considerable intensity and extension in Europe. Their management is currently based on the use of pathogen-free propagation plant material, quarantine and eradication measures, and vector control. However, no cure of the disease exists up to now. Antimicrobial peptides have been identified as potential candidates for plant disease control, and have demonstrated a strong potential for the control of Xf. Specifically, it has been reported that the BP100 derivative peptide, BP178, synthetized for being expressed in plants, show high in vitro antibacterial activity against a collection of Xf strains. Although the application of bactericidal compounds to control xylem and phloem limited bacterial diseases has been tested by spray or trunk injection, the production of transgenic plant lines expressing antimicrobial peptides has been reported as promising alternative in the control of Xf. We have developed a transient-expression system based on Potato virus X (PVX) in Nicotiana benthamiana plants, for the production of the BP178 peptide in plants and evaluation of their potential in controlling Xf. The BP178 sequence was engineered in a PVX viral vector to be expressed in fusion with the NH2 Coat protein terminus. The release of the peptide occurs by the proteolytic activity of a Foot and Mouth Disease Virus 2A sequence. Western blot analysis showed that the BP178-CP fused proteins were expressed in N. benthamiana plants infected with the recombinant PVX-BP178-CP. Co-inoculations of N. benthamiana plants with PVX-BP178-CP and Xff strain IVIA 5387.2 are ongoing with initial results showing efficacy in controlling the pathogen over time.
ES; PPT; laura.montesinos@udg.edu