Phytoene Synthase Gene ( PSY ) from Sweet Potato ( Ipomoea batatas Lam . ) Enhances Tolerance to Abiotic Stress

Abstract

Phytoene synthase (PSY) is the rate-limiting enzyme for carotenoid biosynthesis. To date, several studies focused on PSY genes in the context of abiotic stress responses. In this study, two phytoene synthase encoding genes, IbPSY1 and IbPSY2, were identified from a published transcriptome and bioinformatic analysis showed that they shared conserved domains with phytoene synthases from other plants. The IbPSY1 gene was cloned and carefully characterized. Digital gene expression profiling (DGE) showed that the highest transcription level of IbPSY1 was in young leaves, and the lowest level was in stems. In vivo expression levels of IbPSY1 under abiotic stress were observed to be highest in stems at day 11. Over-expression of IbPSY1 in Escherichia coli and yeast cells endowed the cells with better growth under salt and drought stress than the control cells. This study demonstrated that IbPSY1 not only played an important role in vivo, but also in E. coli and yeast to improve tolerance to salinity and drought stress. Thus, IbPSY1 may be aid in the development of transgenic plants with enhanced stress tolerance.

Flesh Color Diversity of Sweet Potato: An Overview of the Composition, Functions, Biosynthesis, and Gene Regulation of the Major Pigments

“…The purple and red coloration of the leaves, stem, and storage roots of sweet potato results from the accumulation of acylated anthocyanins Orange-fleshed [48]. Peonidin and cyanidin, acylated with either hydroxybenzoic, ferulic, or caffeic acids are the main anthocyanins among the 39 anthocyanins identified in purple-fleshed sweet potato [11,30]. In recent years, anthocyanins from purple-fleshed sweet potato have extensively been studied due to their potential beneficial health effects on humans.…”

“…For instance, IbPSY1, a carotenoid gene was reported to be crucial in plants' resistance to abiotic stress in vivo. In some plant species (daffodil, maize, potato), the upregulation of the PSY gene was reported to highly increase carotenoid levels [11], this then explains the ability of the IbPSY1 gene to increase tolerance to environmental stress including drought, salinity, and high/low temperature which may negatively affect growth and yield of sweet potato. Another gene observed to improve sweet potato resistance to environmental stress is IbOr, a gene involved in carotenoid accumulation, and its overexpression improves resistance to heat stress and oxidative damage [19,85].…”

“…With the orange-and purple-fleshed varieties of sweet potato being the major accumulators of carotenoid and anthocyanin, pigment studies focus on these two types with little information available for the other colors. The nutritional composition, cultivar adaptability, extra-nutritional constituents, and morphological traits may also influence varietal differences [11].…”

Sweet Potato (Ipomoea batatas (L.) Lam): A Review of Modern Varieties and Production Guidelines for Enhanced Food and Nutrition Security

“…Being a drought-tolerant crop, sweet potato is more efficient in using limited available water than non-drought-tolerant crops [54,55]. Drought tolerance in sweet potato is related more to its survival and fast recovery after dry spells than to yield potential under drought conditions [56].…”

A Dual Strategy of Breeding for Drought Tolerance and Introducing Drought-Tolerant, Underutilized Crops into Production Systems to Enhance Their Resilience to Water Deficiency

“…Although, sweet potatoes ( Ipomoea batatas ) cannot be categorized as a NUS, in certain countries, this species is not cultivated and could have high potential, since it shows the ability to grow and produce under adverse conditions. In this species, the role of phytoene synthase (IbPSY1) regulated by the orange protein (IbOr) in abiotic stress tolerance has been confirmed [ 67 , 68 ]. Both proteins are related to carotenoid biosynthesis and accumulation.…”