Metabolomic, Ionomic and Microbial Characterization of Olive Xylem Sap Reveals Differences According to Plant Age and Genotype

Vascular pathogens are the causal agents of main diseases threatening health and growth olive crops worldwide. The use endophytic microorganisms represents a challenging promising strategy for management vascular in olive. Although current research has been focused on analyzing structure diversity microbial communities inhabiting xylem, characterization this ecological niche overlooked to date remain unexplored, despite that xylem sap composition is essential unravel nutritional requirements xylem-limited microorganisms. In study, branches from plantlets adult trees cultivars Picual Arbequina were selected characterize chemical extracted using Scholander pressure chamber. Metabolome ionome analyses performed by proton nuclear magnetic resonance (NMR) spectroscopy-based inductively coupled plasma with optical emission spectroscopy (ICP-OES), respectively. Olive metabolites included higher relative percentage sugars (54.35%), followed alcohols (28.85%), amino acids (8.01%), organic (7.68%), osmolytes (1.12%). Within each these groups, mannitol, ethanol, glutamine, acetic acid, trigonelline, whereas K Cl− element inorganic anion, Metabolomic profile varied when comparing plant age genotype. levels glucose, fructose, sucrose choline, B PO43− significantly than both genotypes, NO3− Rb content showed opposite behavior. On other hand, aspartic phenylalanine, Na ‘Picual’ ‘Arbequina’, Fe behavior, but only trees. Microbiome identified Firmicutes (67%), Proteobacteria (22%) Actinobacteriota (11%) as phyla, while at genus level Anoxybacillus (52%), Cutibacterium (7%), Massilia (6%), Pseudomonas (3%) most representative. Both non-supervised hierarchical clustering analysis supervised PLS-DA differentiated first, according then revealed B, Fe, sucrose, Sr, Anoxybacillus, Cutibacterium, Bradyrhizobium significant compounds bacterial genera, respectively, discrimination plantlets. Knowledge will lead better understanding complex xylem-inhabiting microorganisms, including their potential antagonists, may allow design artificial growing media improve culturing microbiome.