Inferring the Genetic Determinants of Fruit Colors in Tomato by Carotenoid Profiling.

Hee Yoo,Gyu-Myung Lee,Inhwa Yeam,Chang Kim,Dong-Chan Won,Woo Park,Chang-Sik Oh,Je Lee

doi:10.3390/molecules22050764

Abstract

Carotenoids are essential for plant and animal nutrition, and are important factors in the variation of pigmentation in fruits, leaves, and flowers. Tomato is a model crop for studying the biology and biotechnology of fleshy fruits, particularly for understanding carotenoid biosynthesis. In commercial tomato cultivars and germplasms, visual phenotyping of the colors of ripe fruits can be done easily. However, subsequent analysis of metabolic profiling is necessary for hypothesizing genetic factors prior to performing time-consuming genetic analysis. We used high performance liquid chromatography (HPLC), employing a C30 reverse-phase column, to efficiently resolve nine carotenoids and isomers of several carotenoids in yellow, orange, and red colored ripe tomatoes. High content of lycopene was detected in red tomatoes. The orange tomatoes contained three dominant carotenoids, namely δ-carotene, β-carotene, and prolycopene. The yellow tomatoes showed low levels of carotenoids compared to red or orange tomatoes. Based on the HPLC profiles, genes responsible for overproducing δ-carotene and prolycopene were described as lycopene ε-cyclase and carotenoid isomerase, respectively. Subsequent genetic analysis using DNA markers for segregating population and germplasms were conducted to confirm the hypothesis. This study establishes the usefulness of metabolic profiling for inferring the genetic determinants of fruit color.

Highlights

Tomato (Solanum lycopersicum L.) is a model crop for studying the biology of fleshy fruits, especially carotenoid biosynthesis [1]
We investigated the simultaneous use of metabolite profiling and genetic analysis for identifying the genes regulating the fruit color and carotenoid accumulation in tomato
To separate and identify the carotenoid compounds in red tomatoes, carotenoids were extracted from the pericarp of S. lycopersicum ‘LA3475’ (Scheme 2) and analyzed by high performance liquid chromatography (HPLC) using a C30 reverse-phase column and photodiode array detector (PDA) (Figure 1)

Summary

Introduction

Tomato (Solanum lycopersicum L.) is a model crop for studying the biology of fleshy fruits, especially carotenoid biosynthesis [1]. Carotenoids protect the cells from excessive radiation and render various colors, such as yellow, orange, and red to flowers, fruits, and vegetative organs [2]. The bright colors of flowers and fruits attract the pollinators and seed dispersers, and thereby, facilitate the propagation of plants. Carotenoids are precursors of plant hormones, such as abscisic acid (ABA). Strigolactones, as well as of various apocarotenoids [3]. Dietary carotenoids are essential for the health of humans as they are unable to synthesize carotenoids de novo [4]. Each carotenoid has its own function in promoting human health. Β-carotene, the precursor of vitamin A, is essential

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Conclusion