Unraveling the Spatio-Temporal Dynamics of Soil and Root-Associated Microbiome in Texas Olive Orchards: A Comprehensive Analysis

Understanding the structure and diversity of microbiomes is critical to establishing olives in non-traditional production areas. Limited studies have investigated soil and root-associated microbiota dynamics in olives across seasons or locations in the United States. We explored the composition and spatiotemporal patterns in two niches (roots and soils), seasons (spring, summer, and fall), and domains (bacteria and fungi) in the microbiome of the olive variety Arbequina across three olive orchards in Texas to investigate the structure of the olive-associated microbial communities and specificity to the root endosphere and soil rhizosphere zones. The bacterial populations in the rhizosphere (16.42%) and endosphere (15.49%) were dominated by Phylum Proteobacteria , followed by Actinobacteriota (RS, 12.63%; RE, 16.47%). Rubrobacter (5.27%) and Actinophytocola (3.49%) were dominant taxa in the rhizosphere and root endosphere at the genus level. Among fungal communities, phylum Ascomycota was prevalent in the rhizosphere (71.09%) and endosphere (41.37%). Members of the Chaetomiaceae taxon outnumbered (17.61%) another taxon in the root endosphere. As Per the alpha diversity indices, rhizosphere soil at Moulton showed much higher richness and diversity than other places, which predicted a significant difference in rhizosphere between locations for bacterial diversity and richness. There was no significant variation in the bacterial diversity in the niches and the fungal diversity within the root endosphere between locations. Beta diversity analysis confirmed the effect of compartments (Fungi: 12.3%; Bacteria: 45.1%) in influencing community differences. Microbial diversity was apparent within the endosphere (Bacteria:14.6%, Fungi:15.6%) and rhizosphere (30.5%, Fungi: 21.6%). The seasons influenced only the rhizosphere fungal diversity (8.5%), contrasting the bacterial diversity in either niche. The research provided a comprehensive overview of the microbial diversity present in both the rhizosphere and endosphere of olive trees. The abundance and composition of OTUs associated with the rhizosphere soil of Arbequina suggest its role as a source reservoir in defining the potential endophytes.