Glucosinolate content of seedlings, tissue cultures, and regenerant plants of Brassica juncea (Indian mustard)

Abstract

Seeds, cotyledons, and leaves of the Indian Brassica juncea line CPI 81793 all contained (2-hydroxybutenyl) -, [ (4-hydroxyindolyl) methyl] -, pen ten yl-, (indolylmethyl) -, [ (4-methoxyindolyl) methyl] -, (phenylethy1)-, butenyl-, and allylglucosinolates. Butenyl-and allylglucosinolates predominated in all tissues and were also detected in callus tissue and regenerated plants derived from cotyledon cultures.The glucosinolate content of intact 7-day-old cotyledons was similar to that of whole seeds, but thereafter seedling cotyledon glucosinolates declined gradually to approximately 10% of the seed level at 21 days, just before abscission. A rapid decline in glucosinolate content occurred when 7-day-old cotyledons were excised and cultured in vitro, reaching approximately 2% of the seed level after 13 days in culture. Prolific root and shoot regeneration occurred in these cultures, but glucosinolate levels remained very low in all nontransferred cultures. Leaf glucosinolate content increased markedly when regenerant plants were transferred to fresh medium. After 31 days in fresh medium, the leaf glucosinolate content of regenerant plants was comparable to that of mature leaves from 8-week-old seedlings.Agronomic characteristics such as reduced pod-shattering, good tolerance of heat and drought, low erucic acid oil, and high-protein seed meal render modern varieties of Indian mustard potentially valuable alternatives to rapeseed (Brassica napus, Brassica campestrk) in warm and dry climates; however, the usefulness of this crop is still severely limited by the unacceptably high content of goitrogenic glucosinolates in the seed meal (Kirk and Oram, 1978, 1981).Conventional breeding and selection of low-glucosinolate Brassica sp. would be greatly facilitated by a better understanding of the physiology and biochemistry of glucosinolates and the development of improved screening techniques. The recent premature announcement of "glucosinolate-free" lines of Brassica juncea by Cohen et al. (1983) highlights the difficulties that plant breeders face in recognizing heritable differences in glucosinolate metabolism; these workers subsequently found the glucosinolate-free character to be unstable in generations grown after 1983 (W. Thies, personal communication).

A heritable glucosinolate polymorphism within natural populations of Barbarea vulgaris

“…Organs that are most closely linked to plant fitness, such as seeds and flowers, are predicted to be defended constitutively at higher levels than leaf tissue (Zangerl and Nitao, 1998). Indeed, the seeds had the highest total glucosinolate content in both types, which is consistent with earlier findings in other crucifer species, such as Arabidopsis thaliana (Brown et al, 2003), and Brassica juncea (Palmer et al, 1987). Between the types, the anatomical distribution of total glucosinolate contents did not differ.…”

Structure of α-hydroximinopentyl 1-thio-β-D-glucopyranoside

“…They may be detected and analyzed (Palmer, Yeung & Sang, 1987) by treatment with arylsulfatase followed by high performance liquid chromatography of the desulfoglucosinolate, (II).…”

Application of new methodology to canola protein isolation

“…It is generally agreed thaL the glucosi nol-ates ere found in the parenchymal tissue in rapeseed (Mieth et âf., t983; Appelqvist and Ohlson, I972). Various studies have shown the concentration of glucosinolates to be highest in the seed itself, slightJ-y declining with maturity (Kondo et âf., 1985;Palmer et al, 1987;McGregor, 1988).…”