Endophytic bacteria associated with endangered plant Ferula sinkiangensis K. M. Shen in an arid land: diversity and plant growth-promoting traits

Ferula spp. are traditional medicinal plants found in arid land. Large-scale excavation for extracting bioactive compounds from the plants in arid regions of Xinjiang over the last few years has, however, significantly decreased their distributions. Due to the urgent need for preservation of these plant resources, along with the need of searching for alternative source of the useful metabolites, it is important to screen the endophytic microbial resources associated with the plant Ferula sinkiangensis K. M. Shen. In the study, a total of 125 endophytic bacteria belonging to 3 phyla, 13 orders, 23 families, and 29 genera were isolated based on 16S rRNA gene sequencing data. Among the different isolates, three strains isolated from roots were potential novel species of the genera Porphyrobacter, Paracoccus and Amycolatopsis. In this study, 79.4% and 57.1% of the total isolates were capable of producing indole-3-acetic acid (IAA) and siderophore, respectively. And, 40.6% of the strains inhibit the growth of fungal pathogen Alternaria alternata, 17.2% and 20.2% strains were positive for antagonism against Verticillium dahlia 991 and V. dahlia 7, respectively. These results demonstrated that F. sinkiangensis is a rich reservoir of endophytic bacterial resources with potential for production of biologically important functions such as plant growth-promoting factors.