Molecular Basis of Carotenoid Accumulation in Horticultural Crops

Abstract

Carotenoids are isoprenoid pigments, which are widely distributed in nature. In fruits and flowers, carotenoids are responsible for bright yellow, orange, and red colors and provide a substrate to form flavor compounds, which attract pollinators and seed dispersers. In leaves, carotenoids play an essential role in photosynthesis. When carotenoids are ingested in the diet, they play a vital role in human nutrition and health as a precursor of vitamin A, antioxidants, and anti-inflammatory agents. It is therefore important to control carotenoid accumulation to improve the commercial value of horticultural crops. Carotenoid accumulation is regulated by flux through the carotenoid biosynthetic pathway, and also by degradation and sequestration into plastids, which function as sink organelles. These processes are mostly controlled at the transcriptional levels of relevant genes. In this review, we summarize recent advances in studies on the molecular mechanisms that regulate carotenoid accumulation in vegetables, fruits, and ornamental flowers.

Low temperature transcriptionally modulates natural peel degreening in lemon (Citrus limon L.) fruit independently of endogenous ethylene

“…Citrus peel degreening is also complemented by a change in the content and composition of carotenoids having varied colours (Kato, 2012; Ohmiya et al ., 2019). Therefore, we sought to determine the changes in peel carotenoid content triggered by ethylene treatment and storage temperature.…”

“…Phytoene desaturase (PDS) and ζ-carotene desaturase (ZDS) successively convert phytoene to lycopene, which is then converted to either α-carotene or β-carotene by lycopene ε-cyclase (LCYe) and lycopene β-cyclase (LCYb) respectively. α-carotene is later converted to lutein via sequential hydroxylation by ε-ring hydroxylase and β-ring hydroxylase (CHYb), whereas β-carotene is converted to zeaxanthin via β-cryptoxanthin by CHYb (Cunningham et al ., 1996; Ohmiya et al ., 2019). Genes encoding various enzymes for the main steps of chlorophyll degradation and carotenoid metabolism have been isolated and functionally characterized (Rodrigo et al ., 2013).…”

Transcriptome Profiling of Ornithogalum dubium Leaves and Flowers to Identify Key Carotenoid Genes for CRISPR Gene Editing

“…However, most of the transcripts in the carotenoid pathway, including phytoene synthase (PSY), phytoene dehydrogenase (PDS), ζ-carotene desaturase (ZDS), lycopene β-cyclase (LCYB), β-carotene hydroxylase (BCH), etc., were upregulated in flowers. Carotenoids are one of the most widespread pigment groups responsible for bright red, yellow and orange hues in many fruits, vegetables and ornamental plants [13,14]. Previous reports have focused on carotenoid contents in the flower coloration of O. dubium and O. thyrsoides (two morphologically distinct species).…”

“…For O. dubium, a stable transformation and regeneration system has already been established and used to produce hundreds of transgenic plantlets and plants [2,3]. Moreover, it is a relatively straightforward process to identify target genes in the biosynthetic and regulatory pathways of anthocyanin and carotenoid synthesis, because these genes are well-studied and fairly conserved among different plant species [13][14][15][16]. Nevertheless, the genomic resources for O. dubium are scarce, thus limiting the pigment-related target sequences available for editing.…”

Letters to Vavilov Journal of Genetics and Breeding

“…Фиолетовая окраска обусловлена флавоноидными пигментами антоцианами (Nadeem et al, 2011). Разные системы генов и клеточные механизмы контролируют синтез антоцианов и каротиноидов в плодах перца (Liu et al, 2018;Ohmiya et al, 2019). Все названные соединения входят в антиоксидантный пул, однако каротиноиды относятся к жиро-, а антоцианы -к водорастворимым пигментам.…”