Identification of Interacting Proteins of Transcription Factor DpAP2 Related to Carotenoid Biosynthesis From Marine Microalga Dunaliella parva

Abstract

Carotenoids are widely distributed and structurally diverse, which have significant roles in the photosynthesis of plants. As a precursor of vitamin A, carotenoids are also antioxidants that reduce various chronic diseases, which are beneficial for human health. Currently, the existing studies concerned the biological roles of APETALA2 (AP2)/ethylene-responsive factor (ERF) genes originated from higher plants. The AP2 superfamily of the transcriptional regulator was identified in higher plants, which was related to growth, development, carotenoid metabolism, and responses to various stresses. However, the regulatory mechanisms of the AP2-modulating carotenoid metabolism have not been reported in microalgae, which remain to be elucidated. Dunaliella parva AP2 (i.e., DpAP2), an important transcription factor, promotes carotenoid accumulation by binding to the promoter of target gene. Here, we identified an important AP2/ERF transcription factor, DpAP2, which could promote carotenoid accumulation by binding to the promoter of target gene. To demonstrate the function of DpAP2, the interacting proteins were identified by the yeast two-hybrid system. The results showed that DpAP2 could interact with three proteins with different activities (DNA-binding transcription factor activity, protein kinase activity, and alpha-D-phosphohexomutase activity); these proteins may be associated with multiple biological processes. This paper laid a good foundation for a deep understanding of the regulatory mechanisms of DpAP2 and genetic engineering breeding in D. parva.

Emerging technologies for advancing microalgal photosynthesis and metabolism toward sustainable production

“…Specifically, DpAP2 can interact with three proteins, which may be associated with multiple biological processes. This lays a good foundation for a deep understanding of the regulatory mechanisms of DpAP2 and genetic engineering breeding (Shang et al, 2022). Recently, a comprehensive survey of genes and enzymes related to the carotenoid biosynthetic pathway has now been conducted, and structural modeling of three important enzymes, 1-deoxy-D-xylulose 5-phosphate reductase (DXR), 15-cis-phytoene synthase (PSY), and zeta-carotene desaturase (ZDS), has been achieved (Narang et al, 2021).…”

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

“…For algae, overexpression of DpAP2 genes in Dunaliella parva could lead to an increase of carotenoid content; however, the regulatory mechanism of AP2/ERF transcription factors regulating carotenoid metabolism is unclear in algae.…”

“…77 MaEIL9 positively regulated transcription of MaDXR1, MaPDS1, MaZDS1, and MaSPL16 through directly targeting their promoters, thus elevating carotenoid accumulation of banana fruit. 78 For algae, overexpression of DpAP2 genes in Dunaliella parva could lead to an increase of carotenoid content; 79 however, the regulatory mechanism of AP2/ERF transcription factors regulating carotenoid metabolism is unclear in algae.…”

Physiological changes of microalga Dunaliella parva under the treatment of PEG, CaCl2

“…parva FACHB-815 was purchased from Freshwater Algae Culture Collection at the Institute of Hydrobiology (Wuhan, China). Cells of D. parva were cultured in Dm medium described by our previous study [6,22]. D. parva was cultured under light intensity of 34 μmol photons/ (m 2 xs) with day-night cycle (14 h light and 10 h dark) at 25˚C.…”

“…It was found that carotenoids content reached the highest values of 3.11mg/g DW and 2.78mg/g DW under the treatment of 40 ppm CaCl 2 and 80 ppm PEG, which increased by 58.67% and 41.84% compared with control group (1.96mg/g DW). Carotenoids are synthesized from several steps such as desaturation, cyclization, hydroxylation and epoxidation within the plastids [22]. Key enzymes of carotenoids synthesis pathway include DXS, DXR, GGPS, PSY and PDS.…”