Sophorolipids (SLs) are surface-active molecules produced by the non-pathogenic yeast Starmerella bombicola CGMCC 1576. Several genes involved in the synthesis of SLs have been identified. However, the regulation mechanism of the synthesis pathway for SLs has not been investigated. We recently discovered a protein in S. bombicola, which is structurally related to Yarrowia lipolytica YlBro1. To identify the function of the protein SbBro1 in S. bombicola, the deletion, overexpression, and complementary mutant strains were constructed. We found that the deletion mutant no longer produced SLs. Transcriptome analysis indicated that the expression levels of the key enzyme genes of SLs biosynthetic pathway were significantly down-regulated in the Δbro1, especially the expression level of cyp52m1 encoding the first rate-limiting enzyme in SL synthesis pathway was down-regulated 13-folds and the expression of fatty acid β-oxidation-related enzymes was also down-regulated. This study can give insight into the regulation of SL synthesis.

中文翻译：

---

鉴定和表征Starmerella bombicola中槐糖脂合成必需的蛋白质Bro1。

槐糖脂（SLs）是由非致病性酵母Starmerella bombicola CGMCC 1576产生的表面活性分子。已经鉴定了一些参与SLs合成的基因。然而，尚未研究SL的合成途径的调节机制。我们最近在S. bombicola中发现了一种蛋白质，该蛋白质在结构上与解脂耶氏酵母Y1Bro1有关。为了鉴定S. bombicola中蛋白质SbBro1的功能，构建了缺失，过度表达和互补突变株。我们发现缺失突变体不再产生SL。转录组分析表明，SLbros生物合成途径的关键酶基因的表达水平在Δbro1中显着下调，特别是SL合成途径中编码第一个限速酶的cyp52m1的表达水平下调了13倍，脂肪酸β-氧化相关酶的表达也下调了。这项研究可以深入了解SL合成的调控。