Tocochromanols and Chlorophylls Accumulation in Young Pomelo (Citrus maxima) during Early Fruit Development.

Yihan Zhao,Qiuming Gu,Junhao Li,Xinbo Guo,Huayong Li,Yutao Liu,Yuwei Hu,Shaohua Huang

doi:10.3390/foods10092022

Yihan Zhao, Qiuming Gu + Show 6 more

Open Access

https://doi.org/10.3390/foods10092022

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Abstract

Pomelo is an important cultivar of the genus Citrus that contains a variety of beneficial nutrients, and its young fruit is an agricultural by-product that is currently not fully utilized because it is often thrown away during cultivation and management. In this study, the dynamics of tocochromanol during young pomelo development were investigated by measuring chlorophyll content, tocochromanol accumulation, and expression levels of related genes during early fruit development. The results showed that chlorophyll content decreased overall during these four developmental stages and had some synergism with tocochromanol. Four tocochromanol components were detected in pomelo of both genotypes, and α-tocopherol was the main component. The tocochromanol content of honey pomelo was highest in the first period, reaching 70 ± 5 μg/g in dry weight (DW), and golden pomelo peaked in the second period at 86.10 ± 0.18 μg/g DW, with an overall decreasing trend in both genotypes. The different gene expression patterns of the tocochromanol biosynthesis pathway could partially explain the changes in these components and further elucidate the regulatory mechanisms of tocochromanol accumulation during early fruit development. As a natural product, young pomelo fruit is an attractive source of tocochromanol and has potential application in industrial production. The results of this study may provide directions for the high additional value utilization of young pomelo fruit.

Highlights

Introduction published maps and institutional affilTocochromanol is considered an effective fat-soluble natural antioxidant, which is synthesized mainly in photosynthetic organisms such as plants, algae, and some cyanobacteria [1]
Tocochromanol is synthesized by a polar phenolic moiety, p-hydroxyphenylpyruvic acid (HPP), and a polyprenyl side chain derived from isopentenyl diphosphate (IPP)
The results showed that the encoding gene of hydroxyphenylpropanoic acid dioxygenase (HPPD) was up-regulated at S2, but significantly down-regulated at S3 and S4 in honey pomelo

Summary

Introduction

Tocochromanol is considered an effective fat-soluble natural antioxidant, which is synthesized mainly in photosynthetic organisms such as plants, algae, and some cyanobacteria [1]. Studies have found that tocochromanol plays a fundamental biological role in protecting cells and tissues from oxidative damage and other side effects caused by cytotoxic drugs [2]. From the perspective of structure, tocochromanol is a derivative of benzodihydropyran, including tocopherol and tocotrienol. There are eight monomers of tocochromanol, namely α, β, γ, δ-tocopherol and α, β, γ, δ-tocotrienol [3]. Tocopherols widely exist in fruits, leaf chloroplasts, cotyledons, hypocotyls, and stems, and α-tocopherol is the main form of tocochromanol in photosynthetic tissue. Tocochromanol is synthesized by a polar phenolic moiety, p-hydroxyphenylpyruvic acid (HPP), and a polyprenyl side chain derived from isopentenyl diphosphate (IPP).

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