Context: Pinellia ternata (Thunb.) Berit., a perennial herb belonging to Araceae, is one of the few medicinal plants to produce purine alkaloids. It is speculated that endophytic bacteria from P. ternata may produce guanosine or inosine. However, there is no report about endophytic bacteria in P. ternata.
Objective: In this study, endophytic bacteria were isolated from P. ternata and examined for the first time. This study finds a novel way to increase the yield of P. ternata herb, and to provide some new alkaloid producers.
Materials and methods: Plant material includes leaves, tubers, and roots of cultivated and wild P. ternata. The dilutions were smeared onto beef extract-peptone medium and cultured at 28 °C in darkness for 48-72 h. Co-culture treatments were prepared by inoculating 100 mL liquid 1/2 MS medium with bacterial culture broth at concentrations of 0 (control), 0.5%, and 1.5% (v/v).
Results: Of the 34 endophytic bacterial colonies isolated from P. ternata leaves, roots, and tubers, five strains were able to produce purine alkaloids. Results from 16s rDNA sequence analysis indicated that the bacteria belonged to Bacillus cereus, Aranicola proteolyticus, Serratia liquefaciens, Bacillus thuringiensis, and Bacillus licheniformis. Co-culture with living Serratia liquefaciens cells increased PLB growth by 58-71%. Co-culture with living Bacillus licheniformis cells increased PLB growth by 4-11%.
Conclusion: This study provides a novel way for improving the yield of P. ternata herb, and for the production of purine alkaloids by the fermentation industry.
Keywords: Alkaloids; Pinellia ternata; endophytic bacteria; guanosine; herb; inosine; secondary metabolites.