Chemical-genetics based screening for furanonaphthoquinone producing endophytic actinomycetes from seeds of Trewia nudiflora

Abstract:

Abstract:［Objetive］ The seeds of Trewia nudiflora containing maytansine (an anticancer agent)，was investigated to explore the endophytic actinomycetes diversity and screen for naphthoquinones producing strain．［Methods］The seeds of Trewia nudiflora were sliced and plated on different selective media after surface sterilization． Clones that looked like actinomycetes were selected，and classified according to the 16S rRNA sequences． Isolated strains were screened for furanonaphthoquinone biosynthesis gene by PCR， and tested for antibacterial and antifungal activity using Staphyloccocusaureus，Pseudomon-asaeruginosa，Bacillus subtilis，Rhizoctoniasolani and Gibberellasaubinetii． LC-MS and NMR were used to determine the structure of candidate compounds．［Results］ More than 100 endophytic bacteria were isolated． Among them 66 were streptomycetes． FNQ6 (polyketide synthase Type III) and FNQ21 (carboxymuconate cycloisomerase) were only detected in Streptomyces sp． HTZ 27．We got 5 mg pure furanonaphthoquinone (FNQI) from 1 liter Streptomyces sp．HTZ 27 agar fermentation medium． ［Conclusion］ The use of chemical-genetics method increased the efficiency of screening for target compound producing bacteria．