A Comprehensive Gene Inventory for Glucosinolate Biosynthetic Pathway in Arabidopsis thaliana

Abstract

Glucosinolates (GSLs) are plant secondary metabolites comprising sulfur and nitrogen mainly found in plants from the order of Brassicales, such as broccoli, cabbage, and Arabidopsis thaliana. The activated forms of GSL play important roles in fighting against pathogens and have health benefits to humans. The increasing amount of data on A. thaliana generated from various omics technologies can be investigated more deeply in search of new genes or compounds involved in GSL biosynthesis and metabolism. This review describes a comprehensive inventory of A. thaliana GSLs identified from published literature and databases such as KNApSAcK, KEGG, and AraCyc. A total of 113 GSL genes encoding for 23 transcription components, 85 enzymes, and five protein transporters were experimentally characterized in the past two decades. Continuous efforts are still on going to identify all molecules related to the production of GSLs. A manually curated database known as SuCCombase (http://plant-scc.org) was developed to serve as a comprehensive GSL inventory. Realizing lack of information on the regulation of GSL biosynthesis and degradation mechanisms, this review also includes relevant information and their connections with crosstalk among various factors, such as light, sulfur metabolism, and nitrogen metabolism, not only in A. thaliana but also in other crucifers.

Differential Effects of Low Light Intensity on Broccoli Microgreens Growth and Phytochemicals

“…Among 9 glucosinolates in broccoli microgreens, the content of glucoerucin (GER, an aliphatic glucosinolate) was the highest, followed by glucoraphanin (GRA, an aliphatic glucosinolate), which accounted for about 50% and 30% of total glucosinolate, respectively (Table 1). Side-chain modification of GER led to GRA synthesis [37]. Significantly higher GER content in all treatments might lead to the relatively inefficient conversion of GER to GRA [35].…”

Potential Arabidopsis thaliana glucosinolate genes identified from the co-expression modules using graph clustering approach

“…The transcriptional components in GSL biosynthesis were divided into their respective GSL regulatory mechanism, such as activator, repressor, and mediator. The GSL regulatory network would affect several GSL biosynthetic pathways that can be grouped into side-chain elongation, core structure synthesis, co-substrate pathways, and side chain modification ( Harun et al, 2020 ). GSL degradation refers to the formation of activated GSL products that are known to confer protection in plants against the biotic, and abiotic stresses ( Halkier & Gershenzon, 2006 ; Liu et al, 2020 ).…”

“…Tryptophan metabolism pathway was found in the gene network as shown in Fig. 4 where all genes directly linked to tryptophan metabolism are involved in indolic GSLs (Seo & Kim, 2017;Harun et al, 2020). The genes can be grouped based on their function in the indolic GSL biosynthesis: GSL core structure synthesis (CYP79B2, CYP79B3, CYP83B1, SUR1, and UGT74B1), as well as GSL degradation (TGG1, TGG2, and TGG4).…”

“…Before this study, only 46 known GSL genes were identified by Sønderby, Geu-Flores & Halkier (2010) . Following that, we performed a comprehensive literature and pathway databases search in KEGG ( ) ( Kanehisa et al, 2016 ) and AraCyc ( ) ( Mueller, Zhang & Rhee, 2003 ) to identify more known GSL genes using keywords, such as glucosinolate AND Arabidopsis, in journals published in 2020 ( Harun et al, 2020 ). The list of updated GSL genes were also added in our manually curated sulfur compound database, SuCComBase ( ) ( Harun et al, 2019 ).…”

“…Recently ( Harun et al, 2020 ) have compiled a total of 113 known GSL genes with experimental evidences from the published research conducted for the last 20 years. They classified the genes according to their annotation and grouped them into TFs, biosynthetic genes, and protein transporters.…”