Isolation and characterization of endophytic bacteria from medicinal plants ( Berberis aristata and Xanthium strumarium) for Rosemary plant growth promotion

Medicinal plants constitute a diverse range of the endophytic microbes of economical importance. The endophytic microbial communities have a huge potential in promoting the growth and maintaining the health of their host. The present investigation highlights the isolation of endophytic bacteria from the medicinal plants growing around Baru Sahib region and their potential role as bioinoculants to improve the growth of the rosemary plants. In present study, 22 endophytic bacteria from Berberis aristata and Xanthium strumarium were isolated and screened for different plant growth promoting (PGP) attributes of nitrogen fixation, K and P solubilization, and production of indole-3-acetic acid, siderophores, HCN and ammonia. On the basis of PGP attributes, three endophytic bacteria identified using 16S rRNA gene sequencing as Serratia marcescens EU-NLB-03 (N 2 -fixer), Citrobacter freundii EU-NSB-18 (P-solubilizer) and Bacillus cereus EU-KLB-08 (K-solubilizer) were used as bioinoculants for plant growth promotion of rosemary plants in a pot experiment under green house conditions. The PGP endophytic bacterial strains as consortium and single inoculum positively influenced the growth parameters such as root length, shoot length, fresh and dry weight and physiological parameters such as content of chlorophyll, carotenoids, sugar, phenolic and flavonoids of rosemary plants and could be used as bioinoculants for improving agricultural sustainability. To best of our knowledge, the present study is first report of Serratia marcescens , Citrobacter freundii and Bacillus cereus from Berberis aristata and Xanthium strumarium and their role in plant growth promotion of rosemary plants.