Salinity of irrigation water selects distinct bacterial communities associated with Date palm (Phoenix dactylifera L.) root

Saline water irrigation has been used extensively in date palm (Phoenix dactylifera L.) agriculture as an alternative to non-saline freshwater due to water scarcity in hyper-arid environments. However, how saline water irrigation affects date palm root-associated bacterial communities is unknown. Here, we investigated the effect of irrigation sources (non-saline vs saline water) on date palm root-associated bacterial communities and their diversity using 16S rRNA gene metabarcoding. The bacterial richness, Shannon diversity and evenness didn’t differ significantly between the irrigation sources. Soil electrical conductivity (EC) and irrigation water pH were negatively related to Shannon diversity and evenness respectively, while soil organic matter displayed a positive correlation with Shannon diversity. Of total, 40.5% OTUs were unique to non-saline water irrigation and 26% to saline water irrigation. The multivariate analyses displayed strong structuring of bacterial communities according to irrigation sources, and both soil EC and irrigation water pH were the major factors affecting communities. The genera Bacillus, Micromonospora and Mycobacterium were dominated while saline water irrigation whereas contrasting pattern was observed for Rhizobium, Streptomyces and Acidibacter. This study suggests that while saline water irrigation date palm root select specific bacterial taxa, potentially playing a crucial role in alleviating salinity stress of the host.