Metabolite Profiling and Transcriptome Analysis Provide Insight into Seed Coat Color in Brassica juncea

Abstract

The allotetraploid species Brassica juncea (mustard) is grown worldwide as oilseed and vegetable crops; the yellow seed-color trait is particularly important for oilseed crops. Here, to examine the factors affecting seed coat color, we performed a metabolic and transcriptomic analysis of yellow- and dark-seeded B. juncea seeds. In this study, we identified 236 compounds, including 31 phenolic acids, 47 flavonoids, 17 glucosinolates, 38 lipids, 69 other hydroxycinnamic acid compounds, and 34 novel unknown compounds. Of these, 36 compounds (especially epicatechin and its derivatives) accumulated significantly different levels during the development of yellow- and dark-seeded B. juncea. In addition, the transcript levels of BjuDFR, BjuANS,BjuBAN, BjuTT8, and BjuTT19 were closely associated with changes to epicatechin and its derivatives during seed development, implicating this pathway in the seed coat color determinant in B. juncea. Furthermore, we found numerous variations of sequences in the TT8A genes that may be associated with the stability of seed coat color in B. rapa, B. napus, and B. juncea, which might have undergone functional differentiation during polyploidization in the Brassica species. The results provide valuable information for understanding the accumulation of metabolites in the seed coat color of B. juncea and lay a foundation for exploring the underlying mechanism.

Metabolite Profiling and Transcriptome Analyses Provide Insight Into Phenolic and Flavonoid Biosynthesis in the Nutshell of Macadamia Ternifolia

“…These results predict that flavonoids pathway genes expression and the abundance of flavonoids compounds are most likely interlinked with each other. A recent study in Brassica juncea revealed a strong correlation between flavonoids pathway genes expression and the abundance of flavonoids compounds ( Shen et al, 2021 ). Flavonoids pathway genes are well understood in Arabidopsis ( Saito et al, 2013 ), brassica ( Liu et al, 2013 ), and pear ( Feng et al, 2010 ).…”

“…In recent years, multi-omic analyses such as the integration of transcriptomic and metabolomic data have gained much importance to investigate the regulatory mechanism of metabolite substances in plants ( Chen et al, 2014 ; Shen et al, 2021 ). In this regard, mass spectrometry has been broadly applied to analyze the composition and concentration of metabolic substances ( Matsuda et al, 2009 ; Fang et al, 2019 ).…”

Metabolite Characteristics Analysis of Siliques and Effects of Lights on the Accumulation of Glucosinolates in Siliques of Rapeseed

“…However, they had widely been reported in Brassica vegetables, such as Brassica rapa (Padilla et al, 2007;Barbieri et al, 2008;Kim et al, 2010;Baek et al, 2016;Klopsch et al, 2018), Brassica oleracea (Rungapamestry et al, 2006;Wang et al, 2012), Brassica campestris (Chen et al, 2008), B. napus (Kittipol et al, 2019), and Brassica juncea (Sun et al, 2019). In addition, numerous metabolites had also been identified from seeds of Brassica species (Shao et al, 2014;Wang et al, 2018;Qu et al, 2020;Shen et al, 2021), but few were reported in siliques of B. napus. Herein, we identified 22 GSLs from rapeseed siliques (Supplementary Table 2), of which 10 common differential GSLs between GH06 and ZY821 showed significant differences after shading the siliques (Figure 4 and Supplementary Table 3), indicating that these GSLs were synthesized in the siliques of rapeseed, and affected by light factor.…”

“…Numerous metabolites, such as phenolic acid, flavonoids, GSLs, and other hydroxycinamic acid are widely detected in rapeseed ( Qu et al, 2013 , 2020 ; Yin et al, 2019 ; Shen et al, 2021 ), which were easily affected by different kinds of environmental factors in B. napus ( Naguib et al, 2012 ). However, siliques are the dominant photosynthetic organ for supporting the seed filling during late stages in rapeseed ( Tan et al, 2020 ), which should be acted as one of the main parameters for secondary metabolite synthesis.…”

“…napus ( Kittipol et al, 2019 ), and Brassica juncea ( Sun et al, 2019 ). In addition, numerous metabolites had also been identified from seeds of Brassica species ( Shao et al, 2014 ; Wang et al, 2018 ; Qu et al, 2020 ; Shen et al, 2021 ), but few were reported in siliques of B . napus .…”