Olive Trees, Bacteria, Fungi, and High-throughput Screens

Manuel Anguita Maeso, a Ph.D. student, presented at the Nanopore Community Meeting 2021 a short session entitled: “Unravelling the whole genome of olive antagonistic xylem-inhabiting bacteria, to fight vascular plant pathogens in olive trees.” Anguita Maeso is from the Institute for Sustainable Agriculture, CSIC, in Cordoba, Spain. They began with an introduction to the two vascular pathogens affective olive trees: Verticillium dahliae and Xylella fastidiosa. The olive microbiome impacts plant health and plant growth. The objective of the study was to investigate the olive xylem microbiota as a source of biocontrol agents to confer protection against the xylem-inhabiting pathogens V. dahliae and X. fastidiosa.” This is fascinating! The team started by collecting samples from cultivated olive trees and wild olive trees. They selected samples from trees that are susceptible, highly susceptible, and moderately resistant to these organisms. They put branches in a Scholander chamber to extract xylem. In total, they selected 108 xylem bacterial strains. They used TSB as a control culture medium and olive xylem sap and performed a high-throughput fungal-bacterial interaction screen. The team grew numerous plates for several days to identify strains with high effects on the bacteria. Anguita Maeso and team then sequenced the genomes of the isolates. Whole genome sequencing with Nanopore technologies was then used to identify and compare coding sequences. The specific strains and coding sequences may now help determine the genes that will help fight vascular plant pathogens in olive trees. The study used sequencing and high-throughput screening to find a handful of promising isolates.

close up of olive tree leaves and branches
How can high-throughput screening and sequencing help identify biocontrol organisms to protect against olive tree pathogens? Photo by Rafael Rodrigues on Pexels.com