Supplementary Material for: Heterologous Expression of Spinosyn Biosynthetic Gene Cluster in Streptomyces Species Is Dependent on the Expression of Rhamnose Biosynthesis Genes

Spinosyns are a group of macrolide insecticides produced by Saccharopolyspora spinosa. Although S. spinosa
can be used for industrial-scale production of spinosyns, this might
suffer from several limitations, mainly related to its long growth
cycle, low fermentation biomass, and inefficient utilization of starch.
It is crucial to generate a robust strain for further spinosyn
production and the development of spinosyn derivatives. A BAC vector,
containing the whole biosynthetic gene cluster for spinosyn (74 kb) and
the elements required for conjugal transfer and site-specific
integration, was introduced into different Streptomyces hosts in order to obtain heterologous spinosyn-producing strains. The exconjugants of different Streptomyces strains did not show spinosyn production unless the rhamnose biosynthesis genes from S. spinosa genomic DNA were present and expressed under the control of a strong constitutive ermE*p promoter. Using this heterologous expression system resulted in yields of 1 μg/mL and 1.5 μg/mL spinosyns in Streptomyces coelicolor and Streptomyces lividans, respectively. This report demonstrates spinosyn production in 2 Streptomyces
strains and stresses the essential role of rhamnose in this process.
This work also provides a potential alternative route for producing
spinosyn analogs by means of genetic manipulation in the heterologous
hosts.