Some Direct and Indirect Mechanisms of Endophytic Bacteria That Associated with The Medicinal Plant Areva javanica from Shada Al-Asfal Mountain

Abstract

Endophytes are ubiquitous organisms that reside within plant organs and contribute to the growth and well-being of plants. Nevertheless, there is limited knowledge regarding the plant growth-promoting endophytes found in medicinal plants. Therefore, the aims of the present work were to isolate some endophytic bacteria associated with roots, stems, leaves and inflorescences of Aerva javanica, collected from the Shada Alasfal Mountain at Albaha region, Saudi Arabia. After that, they were screened for some of their direct and indirect plant growth-promoting mechanisms. Finally, based upon their internal transcribed spacer 16S rRNA gene sequencing, the isolates were identified. The results showed that the selected endophytes differentially produced IAA and ammonia, and solubilized phosphate as direct mechanisms. In addition, they had exhibited variable capacities to produce some lytic enzymes and HCN beside their antifungal activities. Furthermore, they showed abilities to tolerate some stress conditions. The bacterial endophytes were identified by molecular methods and belonged to the genera of Micrococcus, Enterobacter, Pseudomonas, Delftia and Bacillus. The findings of this study indicated that the bacterial endophytes isolated from Aerva javanica are possessing crucial functions to improve plant growth and could be utilized as biofertilizers or bioagents to establish a sustainable crop production system.