Effects of RKAcat2 overexpression on carotenoid production in Rhodosporidium kratochvilovae

Abstract:

[Background] Acetyl-CoA acetyltransferase (Acat) belongs to thiolase family and it can be classified into two types (I and II). Type II Acat acts as the first rate-limiting enzyme of the mevalonate (MVA) pathway, and its expression level and catalytic activity affect the production of terpenoids and their derivatives. [Objective] To study whether Acat2 overexpression can increase the carotenoid biosynthesis in Rhodosporidium kratochvilovae. [Methods] A gene encoding type II Acat, named RKAcat2, was cloned from R. kratochvilovae strain YM25235 and then introduced into YM25235 for overexpression. [Results] Compared with the control, RKAcat2 overexpression in YM25235 increased the carotenoid content by 50.53% while decreased the lipid content, oleic acid content, and acetyl-CoA level by 22.80%, 17.78%, and 13.64%, respectively. [Conclusion] RKAcat2 overexpression promoted the entry of more acetyl-CoA into MVA pathway. Consequently, the carotenoid biosynthesis in YM25235 was increased, which is consistent with the results of transcriptional analysis of some genes in MVA and carotenoid biosynthesis pathways. This study may provide a reference for further research on improving the contents of carotenoid and its specific compositions in oil-producing red yeast by metabolic engineering.

Key words:Rhodosporidium kratochvilovae;acetyl coenzyme A acyltransferase;gene overexpression;carotenoid;acetyl coenzyme A