Genetic regulation of glucoraphanin accumulation in Beneforté^® broccoli

Abstract

Diets rich in broccoli (Brassica oleracea var italica) have been associated with maintenance of cardiovascular health and reduction in risk of cancer. These health benefits have been attributed to glucoraphanin that specifically accumulates in broccoli. The development of broccoli with enhanced concentrations of glucoraphanin may deliver greater health benefits.Three high-glucoraphanin F1 broccoli hybrids were developed in independent programmes through genome introgression from the wild species Brassica villosa. Glucoraphanin and other metabolites were quantified in experimental field trials. Global SNP analyses quantified the differential extent of B. villosa introgressionThe high-glucoraphanin broccoli hybrids contained 2.5–3 times the glucoraphanin content of standard hybrids due to enhanced sulphate assimilation and modifications in sulphur partitioning between sulphur-containing metabolites. All of the high-glucoraphanin hybrids possessed an introgressed B. villosa segment which contained a B. villosa Myb28 allele. Myb28 expression was increased in all of the high-glucoraphanin hybrids. Two high-glucoraphanin hybrids have been commercialised as Beneforté® broccoli.The study illustrates the translation of research on glucosinolate genetics from Arabidopsis to broccoli, the use of wild Brassica species to develop cultivars with potential consumer benefits, and the development of cultivars with contrasting concentrations of glucoraphanin for use in blinded human intervention studies.

A 2-Oxoglutarate-Dependent Dioxygenase Mediates the Biosynthesis of Glucoraphasatin in Radish

“…In many pharmacological studies, sulforaphane, an isothiocyanate derived from glucoraphanin (4-methylsulfinylbutyl glucosinolate), has been shown to have health-promoting activities (Juge et al, 2007). To increase the glucoraphanin composition, a MYB28 allele derived from the wild species Brassica villosa was introgressed into broccoli (B. oleracea var italica; Traka et al, 2013). These metabolite-engineering efforts permit the breeding of new vegetables beneficial to human health.…”

Accumulation of Glucosinolates in Broccoli

“…Recently, researchers of this group cloned the major dominant QTL and identified an MYB28 allele resulted in higher expression of MYB28 in the leaves of highglucoraphanin hybrids compared to the standard broccoli cultivars. There are three SNPs identified in the MYB28 allele: two located in the intronic region upstream of exon 3 and one at the 5'-end of exon 3 [120]. Sotelo et al [121] used a DH mapping population of F 1 from a Chinese kale and a DH broccoli line to detect the significant QTLs in leaves, flower buds, and seeds.…”

“…A high-glucoraphanin commercial hybrid, Beneforté ® , was developed by Mithen's group through genome introgression from the wild species Brassica villosa [120]. In former surveys of this group, a major quantitative trait locus (QTL) on linkage group 2 that determined the concentrations of methionine-derived glucosinolates in the high-glucoraphanin hybrids was found, and a microsatellite marker OI12-F02 originated from a wild species Brassica villosa was developed [68,91].…”

Biosynthesis of cabbage phytoalexins from indole glucosinolate

“…Small molecules produced by crucifers, especially the glucosinolate family of natural products, have been implicated in these beneficial effects on both agriculture and human health. For example, accumulated evidence for the link between certain glucosinolates and cancer prevention has motivated an intensive breeding campaign to produce Brassica varieties that contain elevated levels of these molecules (7). These plants are currently commercially available and the subject of major human dietary intervention studies (8), one of the first of its kind where the effect of altered metabolite content in an edible plant on human disease prevention is being investigated.…”