The study of microbial endophytes is a promising research area for selecting possible biocontrol agents against Xylella fastidiosa. Plant scientists have already unraveled some of the microbiome-related mechanisms inhibiting the multiplication of the bacterium in resistant grapevines. But very little is known about the interaction of X. fastidiosa with the microbial population in the olive xylem vessels and its potential role in limiting infections.
XF-Actors scientists investigated the effect of X. fastidiosa infection on the xylem microbiome in field-grown trees of susceptible (Kalamata) and resistant (FS17) olive cultivars. Researchers screened the plants, collecting genetic sequences, in two different stages and seasons.
In both cultivars, the analysis showed that X. fastidiosa suppresses the diversity of the microbiome. However, in the resistant cultivar FS17, this characteristic appeared mitigated and X. fastidiosa average abundance ratio over total bacteria was reduced.
However, the host cultivar had a negligible effect on the microbial community composition. Scientists found no clear associations of a single taxon or microbial consortia with the resistant cultivar. The results suggest that resistance mechanisms likely lie on factors that are independent of the microbiome structure.
Overall, Proteobacteria, Actinobacteria, Firmicutes, and Bacteriodetes dominated the bacterial microbiome while Ascomycota and Basidiomycota those of Fungi.