Study of the Relationship between Leaf Color Formation and Anthocyanin Metabolism among Different Purple Pakchoi Lines

Abstract

Purple pakchoi (Brassica rapa ssp. Chinensis) is particularly appreciated due to its high edible quality and ornamental value, but there are few studies on the underlying mechanisms of leaf color formation. To comprehensively assess the differences in purple formation in pakchoi, four lines of pakchoi with different purple leaves were used in this experiment to determine the pigment content and to investigate the distribution and components of anthocyanin using LCMS (Liquid Chromatography Mass Spectrometry) and leaf cross-sections. Moreover, the expression levels of anthocyanin synthesis-related genes in four lines were calculated by qRT-PCR. The results showed that three new purple lines rich in anthocyanin and of high-quality were bred, and the anthocyanin were mainly distributed in both the upper epidermis and lower epidermis of leaves. Thirteen anthocyanin components were separated and identified, all the anthocyanins were acylated and glycosylated cyanidins; the main anthocyanins in purple pakchoi were a diacylated form of cyanidin 3-trans-(feruloyl)diglucoside-5-(malonyl)glucoside. Both the ratio of non-aromatic acylated cyanidin to aromatic acylated cyanidin and the ratio of anthocyanin content to chlorophyll content were responsible for the color formation in different purple pakchoi lines. When the ratio was high, the leaf appeared reddish purple, and when the ratio was low, the leaf appeared deep purple, even blackish purple. The expression level of BrF3H was significantly correlated with the content of anthocyanin through the correlation coefficient, which was speculated to be the main anthocyanin synthesis-related gene resulting in color differences among the four purple pakchoi lines. These results will enhance our understanding for the cultivation of new purple pakchoi varieties.

Unraveling the Mechanism of Purple Leaf Formation in Brassica napus by Integrated Metabolome and Transcriptome Analyses

“…The anthocyanin content in B. napus leaves was determined and found to correspond with color intensity, which was 7.66–65.34 mg 100 g –1 FW in the green to purple leaves of B. napus ( Figures 1A–C ). Furthermore, anthocyanin was accumulated on the adaxial surface of B. napus leaves ( Figures 1A,B ), which is consistent with results of a previous study on B. napus ( He et al, 2021b ), however, inconsistent with those related to B. juncea ( Heng et al, 2020b ) and B. rapa ( Song et al, 2020b ). The marked difference in anthocyanin accumulation and distribution may be due to differences in cultivars and heredity ( He et al, 2021b ).…”

“…It is well-known that cyanidin, delphinidin, pelargonidin, peonidin, petunidin, and malvidin are common anthocyanin pigments ( Jaakola, 2013 ). In general, cyanidin and peonidin are classified as red pigments, delphinidin, petunidin, and malvidin are categorized as blue pigments ( Song et al, 2020b ), and pelargonidin as an orange and red pigment ( Khoo et al, 2017 ). Purple color is produced by combining red and blue pigments ( Song et al, 2020b ).…”

The Potential of High-Anthocyanin Purple Rice as a Functional Ingredient in Human Health

“…The purple rice is highly valued, particularly among the health-conscious consumers as a functional compound for human health among everyday sources of carbohydrate [12]. In other staple food crops, anthocyanin has been reported in purple maize, a variety that is rarely consumed in comparison with other non-staple food crops such as Brassica, Solanaceous species, and some edible flowers [13][14][15][16]. Additionally, anthocyanin can be directly taken from the concentrate in capsules for convenience, but this can be quite expensive [17,18].…”

Transcriptome Analysis and Metabolic Profiling of Anthocyanins Accumulation in Loropetalum Chinense var. Rubrum With Different Colors of Leaf

“…The color formation of leaves was due to the interaction of pigments such as chlorophyll, anthocyanin, and carotenoid, and the ratio of anthocyanin to chlorophyll content would affect the color presentation of plants [39]. From our ndings, the content of the photosynthetic pigment in GL was higher than those in ML and PL, while the anthocyanin content in ML and PL was signi cantly higher than it in GL.…”