Abstract
Actinobacteria have received much attention due to their capacity for plant growth promotion, a promising approach in sustainable development of agriculture. Date palm (Phoenix dactylifera L.) is an important crop, particularly in semi-arid regions of the world, due to the high nutritional and health-promoting values of its fruits. The present study was conducted to investigate the utilization of actinobacteria as an approach to support soil fertility and enhance production and functional food value of date palm fruits in a semi-arid environment. To achieve this purpose, actinobacterial strains were isolated from palm rhizosphere, characterized and screened for bioactivity. Then the potent isolates, based on plant growth promoting assays, were inoculated into the soil rhizosphere of five-target palms (Ajwa, Sokary, Khodry, Rashodia and Saffawy) before flowering and during fruiting stages in two successive seasons. Interestingly, the actinobacterial inoculants increased soil fertility and improved fruit yield of the tested palms. The treated date fruits accumulated higher levels of valuable phytochemicals such as sugars, organic acids, essential amino acids, unsaturated fatty acids, phenolic acids, flavonoids, vitamins and minerals, as compared with the untreated ones. Moreover, actinobacterial treatment induced the biological activities (antioxidant, antibacterial, antifungal and anticancer) of the produce dates. Conclusively, results presented herein suggest the promising application of actinobacteria for supporting the production and functional food value of date palms in semi-arid regions.