Exploring the Mechanisms Underlying Petal Pigmentation Differences in Two Cultivars of <i>Physalis philadelphica</i> Based on HPLC and NGS

Abstract

Physalis philadelphica, a member of the Solanaceae family, commonly known as Physalis, is a one-year-old herbaceous plant with both medicinal and edible properties, as well as ornamental value. At present, only limited research is available on the flower color of P. philadelphica. This study aimed to elucidate the metabolic characteristics underlying the flower color of P. philadelphica and to identify key genes associated with flower color metabolism. We selected two representative varieties of P. philadelphica with significant differences in flower color, namely, “Tieba” (yellow flower) and “Qingjin” (yellow-purple flower), as the experimental materials. The analysis of related pigment components and the determination of relative content by high-performance liquid chromatography were conducted to investigate the flower color-related metabolic pathways of P. philadelphica. Through next-generation sequencing, these pathways were further investigated for the characteristics and differentially expressed genes (DEGs) associated with flower color formation. The results of the research show that: Anthocyanin is the main component of petal coloring of P. philadelphica var. Qingjin, while malvidin pigment, pelargonidin, delphinidin, and cyanidin are the main components of flower color intensity. Carotenoids are the main components of the petal coloring of P. philadelphica var. Tieba and β-carotene is the main component of flower color intensity. Comparing different developmental stages of these two kinds of Physalis pubescens, we identified two key transcription factors (TFs) (eBP and STAT) that were involved in the inhibition of anthocyanin synthesis and regulate the inhibition of pf05G124640 (dihydroflavonol 4-reductase) and pf09G224140 (anthocyanin synthase) in anthocyanin synthesis. One heat shock transcription factor was found to regulate the flavonoid and flavonol synthesis pathway of pf01G020090 (anthocyanin 3-O-glucosyltransferase); two key TFs (NAC and G2-Like), pf10G255070 (isoricin dehydrogenase) and pf09G237080 (abscisic acid 8′-hydroxylase), played important roles in carotene biosynthesis. This study provides new insights for further exploration of the genetic diversity of petal coloring in P. philadelphica and establishes a foundation for subsequent molecular breeding efforts.

Keywords

• <i>Physalis philadelphica</i>
• petal coloring
• anthocyanin
• carotenoid
• transcription factor