Abstract:

The chemical interactions between endophytes and plant hosts have been an interesting topic since the coining of the concept of symbiosis and co-evolution. Streptomyces sp. WXC was an endophytic strain isolated from the seed of Trewia nudiflora. Culture medium optimization revealed that supplemented with the aqueous extract of T. nudiflora seeds, S. sp. WXC grew faster, and the production of frenolicin B was increased by ca. 3-fold as well. Real-time PCR analysis revealed that the expression levels of frenolicin B biosynthetic genes were induced by the seed extract, which correlated to the increased production of frenolicin B indicated by HPLC analysis. These results indicated that host’s chemical components may induce the endophytic S. sp. WXC to increase the production of antifungal compound. This work shows, for the first time, that intimate chemical interaction exists between endophytic actinomycete and its host.

Key words: T. nudiflora seed extract, Streptomyces sp. WXC, Frenolicin B, Biosynthetic genes