The date palm (Phoenix dactylifera) is a crucial crop in arid regions. In this study, we examined how plant genotype and fertilizer type affect the eukaryotic communities in the date palm rhizosphere. Samples were taken from one wild population, five cultivars from two farms, and a factorial fertilizer experiment involving organic, chemical, and biofertilizers in Qatar. The eukaryotic communities were sequenced using next-generation sequencing, revealing 2,422 Operational Taxonomic Units (OTUs) across 15 phyla, with Chlorophyta, Streptophyta, Imbricatea, Chytridiomycota, Ascomycota, and Olpidiomycota being the most dominant.
Wild date palms exhibited fewer OTUs than cultivated palms, likely due to higher soil salinity and lower moisture. However, wild palms had the highest number of unique OTUs. Principal Component Analysis (PCA) showed that the eukaryotic microbiomes of wild palms were distinct from those of cultivated palms, and diversity varied among cultivars in similar conditions. High levels of biofertilizers and chemical fertilizers reduced species diversity, whereas combining high biofertilizer concentrations with low chemical fertilizer levels enhanced diversity.
We conclude that both cultivar type (biotic factor) and fertilizer type and dosage (abiotic factors) significantly influence rhizosphere microbiome diversity. The wild date palm population may harbor salt- and drought-tolerant eukaryotes, which should be further explored for developing biofertilizers suited to dry environments.