Composition and content of glucosinolates in developing Arabidopsis thaliana

Abstract

The glucosinolate composition and content in various tissues of Arabidopsis thaliana (L.) Heynh. ecotype Columbia during development from seeds to bolting plants were determined in detail by high-performance liquid chromatography. Comparison of the glucosinolate profiles of leaves, roots and stems from mature plants with those of green siliques and mature seeds indicated that a majority of the seed glucosinolates were synthesized de novo in the silique. A comparison of the glucosinolate profile of mature seeds with that of cotyledons indicated that a major part of seed glucosinolates was retained in the cotyledons. Turnover of glucosinolates was studied by germination of seeds containing radiolabelled p-hydroxybenzylglucosinolate (p-OHBG). Approximately 70% of the content of [14C]p-OHBG in the seeds was detected in seedlings at the cotyledon stage and [14C]p-OHBG was barely detectable in young plants with rosettes of six to eight leaves. The turn-over of p-OHBG was found to coincide with the expression of the glucosinolate-degrading enzyme myrosinase, which was detectable at very low levels in seedlings at the cotyledon stage, but which dramatically increased in leaves from plants at later developmental stages. This indicates that there is a continuous turnover of glucosinolates during development and not only upon tissue disruption.

Exogenous glucosinolate produced by Arabidopsis thaliana has an impact on microbes in the rhizosphere and plant roots

“…DNA-SIP and continuous labelling of plant allow showing the global impact of glucosinolates and derivatives on active and growing microbial communities in rhizosphere. It could also be interesting to follow the temporal variations of microbial community structure during the plant growth (Petersen et al, 2002;Brown et al, 2003). An RNA-SIP approach combined with pulse labelling could be adequate for detection of punctual changes in active populations at a determined stage during plant culture.…”

Occurrence and formation of indole-3-acetamide in Arabidopsis thaliana

“…ii. IAN is abundant in seeds and very young plants (Müller et al 1998), as is the IAN precursor, glucobrassicin (Petersen et al 2002).…”

“…Seed glucosinolates are rapidly metabolized during the onset of germination (Elliot and Stowe 1971;Bodnaryk and Palaniswamy 1990) including glucobrassicin, a major seed glucosinolate in A. thaliana (Petersen et al 2002). iv.…”

Metabolite profiling of Arabidopsis seedlings in response to exogenous sinalbin and sulfur deficiency

“…However, the mechanism of glucosinolate catabolism is still unknown. Increased turnover of sinalbin (1) was found to coincide with elevated levels in activity of the glucosinolate-degrading enzyme myrosinase, which indicated the possibility that there was a continuous turnover of glucosinolates mediated by myrosinase during development and not only upon tissue disruption (Petersen et al, 2002). However, in extracts of sinalbin (1)-supplemented plants, although the nitrile breakdown product of sinalbin was detected and shown to be an artifact of extraction, other nitriles or isothiocyanates generated by in vivo myrosinase activity were not detected and the contents of SO 2À 4 relative to sulfur-deficient plants decrease.…”

“…These results suggest that plants can use sinalbin (1) as a sulfur source and under sulfur-deficient conditions glucosinolate can be catabolized to release sulfur to support primary metabolic processes, such as protein synthesis. Glucosinolate catabolism is evident in the fate of radiolabelled sinalbin (1) taken up by germinating Arabidopsis seeds (Petersen et al, 2002). In seedlings at the cotyledon stage, approximately 30% of radiolabelled glucosinolate was lost and in young plants with rosettes of six to eight leaves, radiolabelled glucosinolate could not be detected.…”