刺糖多胞菌合成多杀菌素的基因研究

Study on Spinosad Synthetic Genes in Saccharopolyspora spinosa

多杀菌素是由刺糖多孢菌产生的一种新型大环内酯类混合次级代谢产物,为新型、高效、安全的生物杀虫剂。该类化合物由一个12元大环内酯以及一个中性糖和一个胺糖构成。多杀菌素生物合成基因大部分聚集在刺糖多孢菌基因组上约80kb大小的区域中。该区域DNA已被完全测序,并通过破坏目的基因的方法,对这一区域DNA的特性和功能进行了深入研究。多杀菌素生物合成基因簇包括5个编码I型聚酮合成酶的基因和14个与大环内酯结构修饰有关的基因,另外还有4个编码鼠李糖的基因未包含在上述基因簇中。

As a serial of novel, efficient and safe bio-insecticides, spinosad are produced by Saccharopolyspora spinosa and are catalogued into macrolide secondary metabolites. These compounds are composed by one neutral sugar （rhamnose）, an amino sugar （forosamine）, and a 5,6,5-tricyclic ring system fused to a 12-membered macrocyclic lactone. In the bacteria producing these compounds, most of the macrolide biosynthetic genes clustered together in a 70-80kb region of the genome. DNA in this region has been sequenced and the character and function of it has been intensively studied by interrupting target gene. The gene clusters in charge of spinosad biosynthesis include 5 genes encoding polyketide synthase type I （PKS- I ）, 14 genes required for modification ofmacrolide. Another 4 genes encoding for rhamnose are not included in the above-mentioned gene clusters.