Microscopic Analyses of Fruit Cell Plastid Development in Loquat (Eriobotrya japonica) during Fruit Ripening

Abstract

Plastids are sites for carotenoid biosynthesis and accumulation, but detailed information on fruit plastid development and its relation to carotenoid accumulation remains largely unclear. Here, using Baisha (BS; white-fleshed) and Luoyangqing (LYQ; red-fleshed) loquat (Eriobotrya japonica), a detailed microscopic analysis of plastid development during fruit ripening was carried out. In peel cells, chloroplasts turned into smaller chromoplasts in both cultivars, and the quantity of plastids in LYQ increased by one-half during fruit ripening. The average number of chromoplasts per peel cell in fully ripe fruit was similar between the two cultivars, but LYQ peel cell plastids were 20% larger and had a higher colour density, associated with the presence of larger plastoglobules. In flesh cells, chromoplasts could be observed only in LYQ during the middle and late stages of ripening, and the quantity on a per-cell basis was higher than that in peel cells, but the size of chromoplasts was smaller. It was concluded that chromoplasts are derived from the direct conversion of chloroplasts to chromoplasts in the peel, and from de novo differentiation of proplastids into chromoplasts in flesh. The relationship between plastid development and carotenoid accumulation is discussed.

Carotenoid Biosynthesis and Plastid Development in Plants: The Role of Light

“…Fruits are sink organs that store mainly sugars and pigments such as carotenoids [ 100 ], which accumulate at high levels in chromoplasts in crystals-like structures or plastoglobules [ 101 , 102 , 103 , 104 ].…”

Research on physicochemical properties, microscopic characterization and detection of different freezing-damaged corn seeds

“…The seed embryos of each treatment were selected for TEM observation. In order to better understand the effect of freezing damage on the seed coat and seed embryo cells, a series of pre-observation processing steps were conducted on the selected samples to be suitable for observing the relevant microscopic changes ( Liu et al, 2022 , Lu et al, 2019 ).…”

Expression of a Chromoplast-Specific Lycopene β-Cyclase Gene (CYC-B) Is Implicated in Carotenoid Accumulation and Coloration in the Loquat

“…They are also significant precursors for the biosynthesis of metabolites, such as vitamin A, strigolactone, and abscisic acid [12][13][14][15][16]. Furthermore, carotenoids are thought to protect the human body from oxidative stress by removing free radicals, which can prevent cancer, cardiovascular diseases, and other chronic diseases [17][18][19].Sites for the biosynthesis and accumulation of plant carotenoids are plastids, containing chloroplasts and chromoplasts [20]. The plant carotenoid biosynthesis and cleavage pathway is shown in Supplementary Figure S1.…”

“…Sites for the biosynthesis and accumulation of plant carotenoids are plastids, containing chloroplasts and chromoplasts [20]. The plant carotenoid biosynthesis and cleavage pathway is shown in Supplementary Figure S1.…”