Regulation of a novel DsGATA1 from Dunaliella salina on the synthesis of carotenoids under red light

Abstract

Background Dunaliella salina is a high-quality industrial effector for carotenoid production. Although the accumulation of carotenoids in D. salina increases under red light conditions, the content of carotenoids in the algal cell decreases. The mechanism by which red light regulates carotenoid synthesis is still unclear.Results In this study, a transcription factor of DsGATA1 with a distinct structure was discovered in D. salina. The recognition motif of DsGATA1 was comparable to that of plant and fungal GATA, despite its evolutionary proximity to animal-derived GATA. The expression of DsGATA1 in D. salina was still noticeably decreased when exposed to red light. Analysis of physiological and biochemical transcriptomic data from overexpressed, interfering and wild-type strains of DsGATA1 revealed that DsGATA1 acts as a global regulator of D. salina carotenoid synthesis. The upregulated genes in the CBP pathway by DsGATA1 were involved in its regulation of the synthesis of carotenoids. DsGATA1 also enhanced carotenoid accumulation under red light by affecting N metabolism. DsGATA1 was found to directly bind to the promoter of nitrate reductase to activate its expression, promoting D. salina nitrate uptake and accelerating biomass accumulation. DsGATA1 affected the expression of the genes encoding GOGAT, GDH and ammonia transporter proteins. Moreover, our study revealed that the regulation of N metabolism by DsGATA1 led to the production of NO molecules that inhibited carotenoid synthesis. However, DsGATA1 significantly enhanced carotenoid synthesis by NO scavenger removal of NO. The D. salina carotenoid accumulation under red light was elevated by 46% in the presence of overexpression of DsGATA1 and NO scavengers.Conclusion It was found that a transcription factor of DsGATA1 from D. salina has a distinct structure and recognition motif. The novel gene encoding DsGATA1 enhanced the production of carotenoids under red light and endowed D. salina with high algal biomass. The regulation of terpenoid metabolism by DsGATA1 is different from that reported for GATA factors. DsGATA1 yet enhanced the production of NO in D. salina. Nevertheless, our results indicated that DsGATA1 could be an important target for engineering carotenoid production.

Involvement of Transcription Factors and Regulatory Proteins in the Regulation of Carotenoid Accumulation in Plants and Algae

“…Additionally, other transcription factors such as tomato SlBBX20, banana MaSPL16, papaya CpSBP1, and chrysanthemum CmGATA4 are also involved in the regulation of carotenoid metabolism (Table ), indicating that transcription factors are species-specific to this regulatory process and the involved transcription factors are diversified. There are novel transcription factors such as DsGATA1 from the green alga Dunaliella salina involved in the regulation of carotenoid metabolism, indicating the complexity and diversity of this regulatory process.…”