The influence of endophytic bacteria on plants and animals’ response to infections is renowned, although many details are still missing. Microbial endophytes can protect plants against pathogens and represent a promising research area for controlling xylem-colonizing pathogens, such as Xylella fastidiosa.
The vast majority of microbial communities inhabiting the olive xylem, however, is still unknown. This work provides new insights into the olive xylem microbiome, characterizing the bacterial taxa that shape the olive xylem sap microbial communities. Researchers used culture-dependent and culture-independent approaches, determining to which extent the type of plant extract, the olive genotype and the culture media affect the composition, diversity, and structure of the isolated xylem sap bacterial microbiome.
The results indicated significant differences in the bacterial communities detected in the xylem sap depending on the genotype of the olive tree studied and, to a minor extent, on the type of sap extraction method used. Some of the xylem-inhabiting bacteria isolated are known biocontrol agents of plant pathogens. For others, this paper provides the first report on their presence in olive trees, and their potential role in protecting olive trees against xylem pathogens requires further research.