Genetic Variation in Glucosinolate Content Within Brassica Rapa Vegetables

Abstract

Glucosinolates (GSs) were analyzed in 56 accessions of Brassica rapa grown in the greenhouse. Eight different glucosinolates were identified in the Brassica rapa group. They are the aliphatic glucosinolates progoitrin (PRO), gluconapin (NAP), glucobrassicanapin (GBN), the indolyl glucosinolates 4-hydroxyglucobrassicin (4OH), glucobrassicin (GBC), 4-methoxyglucobrassicin (4ME), neoglucobrassicin (NEO) and the aromatic glucosinolate gluconasturtiin (NAS). Gluconapin, glucobrassicanapin, progoitrin and gluconasturtiin are the most abundant GSs in the Brassica rapa, but there is considerable variation in content among accessions. The total glucosinolate contents in Brassica rapa group varied substantially between the different accessions. The highest amount of GSs (361 mol/100 g FW) was observed in leaves of vegetable turnip, followed by rapid cycling and yellow sarson, with the amount of 200 and 178 mol/100 g FW respectively. Whereas the lowest GSs content was found in turnip greens (20.8 mol/100 g FW) and Wutacai (22.6 mol/100 g FW). The total aliphatic GSs proportion varied from 50 to 90% of the total GS, while generally the content of indolyl glucosinoloates, especially 4OH glucobrassicin and neoglucobrassicin is low. Gluconasturtiin was found in relatively high concentrations in komastsuna (14.6 μmol/100 g FW), yellow sarson (7.1 μmol/ 100 g FW) and constitutes as much as 24% of the total amount of glucosinolates. Relatively high amounts of gluconapin (281 mol/100 g FW) and glucobrassicanapin (60.0 mol/100 g FW) were observed in the leaves of vegetable turnip. Compared with the Brassica oleracea group, Brassica rapa lacks glucoraphanin and sinigrin but contains gluconapin and glucobrassicanapin. Variations in glucosinolate content among genotypes suggest differences in their health-promoting properties and the opportunity for enhancement of their levels through breeding or genetic modification.

Variability of Glucosinolates in Pak Choy (Brassica rapa subsp. chinensis) Germplasm

“…However, the least detected GSL was GBC according to He and co-workers [ 30 ], contrasting with the Sinalbin (SNB) compound that is observed in our current study [ 31 ]. Clear variations in GSL content and individual GSL profiles exists among Brassica vegetables [ 30 , 32 ]. For example, leaf mustard ( B. juncea ), turnips ( B. rapa var.…”

“…Previous studies on GSLs from various B. rapa vegetables revealed that choi sum has high GNA content compared to other Brassica vegetables [ 12 , 30 ]. However, the least detected GSL was GBC according to He and co-workers [ 30 ], contrasting with the Sinalbin (SNB) compound that is observed in our current study [ 31 ]. Clear variations in GSL content and individual GSL profiles exists among Brassica vegetables [ 30 , 32 ].…”

“…sabellica ) exhibit higher total GSL levels compared to pak choy and choy sum ( B. chinensis var. parachinensis ) [ 30 ]. While aliphatic GSLs are generally abundant in Brassica species [ 33 ], choi sum and Chinese cabbage mainly contain GNA and GBN [ 24 ].…”

Glucosinolate Diversity Analysis in Choy Sum (Brassica rapa subsp. chinensis var. parachinensis) Germplasms for Functional Food Breeding

“…Finally, glucobrassicin, an indolic GSL was detected at an average of 333.30 µmol·kg −1 DW, accounting for 3.62% of the total GSLs ( Figure 1 ). Several studies have been made on the GSL content of plants, especially Brassica vegetables [ 12 , 18 , 25 , 26 , 27 ]. Earlier studies on the GSLs from various rapa vegetables indicated that choy sum possessed specifically high levels of GNA among the GSLs compared to other vegetables of Brassica [ 18 , 25 ].…”

“…Several studies have been made on the GSL content of plants, especially Brassica vegetables [ 12 , 18 , 25 , 26 , 27 ]. Earlier studies on the GSLs from various rapa vegetables indicated that choy sum possessed specifically high levels of GNA among the GSLs compared to other vegetables of Brassica [ 18 , 25 ]. However, the least detected GSL was GBC in the case of He et al, 2003, against SNB observed in the current study [ 18 ].…”