Molecular evolution and diversification of phytoene synthase (PSY) gene family

Abstract

Phytoene synthase (PSY) is a crucial enzyme required for carotenoid biosynthesis, encoded by a gene family conserved in carotenoid-producing organisms. This gene family is diversified in angiosperms through distinct duplication events. Understanding diversification patterns and the evolutionary history of the PSY gene family is important for explaining carotenogenesis in different plant tissues. This study identified 351 PSY genes in 166 species, including Viridiplantae, brown and red algae, cyanobacteria, fungi, arthropods, and bacteria. All PSY genes displayed conserved intron/exon organization. Fungi and arthropod PSY sequences were grouped with prokaryote PSY, suggesting the occurrence of horizontal gene transfer. Angiosperm PSY is split into five subgroups. One includes the putative ortholog of PSY3 (Subgroup E3) from eudicots, and the other four subgroups include PSY from both monocots and eudicots (subgroups E1, E2, M1, and M2). Expression profile analysis revealed that PSY genes are constitutively expressed across developmental stages and anatomical parts, except for the eudicot PSY3, with root-specific expression. This study elucidates the molecular evolution and diversification of the PSY gene family, furthering our understanding of variations in carotenogenesis.

Functional Characterization of the First Bona Fide Phytoene Synthase in Red Algae from Pyropia yezoensis

“…Because of the conservation of carotenoid biosynthesis, PSY has been extensively investigated via homology searching and pigment complementary characterization, especially in crops, fruits and microalgae [ 6 , 10 ]. It has been predicted that carotenoid biosynthetic genes are present in many algae [ 12 ]; however, no phytoene synthase has been functionally characterized.…”

“…To date, these genes have been characterized in many organisms, such as Arabidopsis thaliana , Oryza sativa , Triticum aestivum , etc. In some land plants, PSYs are encoded by a small gene family and have different functions [ 10 ]. The sub-functions of PSY enable the accumulation of carotenoids in non-photosynthetic tissues responding to environmental stresses and provide various regulatory mechanisms for carotenoid biosynthesis [ 2 ].…”

“…The active site structure of extant PSYs resembles those of their progenitors, further proving the prokaryote origin of the carotenogenic genes [ 14 ]. The sub-functionalization of PSYs in land plants might be a result of gene duplication and subsequent loss from a common progenitor [ 10 ].…”

Comparison of Bioactive Compounds and Antioxidant Activities in Differentially Pigmented Cerasus humilis Fruits

“…PSY is the first key rate-limiting enzyme in the carotenoid biosynthesis pathway [33]. Overexpression of PSY in maize callus has been found to significantly increase the accumulation of carotenoids (p < 0.05) [34].…”