Effect of sulphur levels on transgenic double-low Brassica napus plants expressing a seed-specific gene encoding a methionine-rich 2S albumin

The effects of supplying varying levels of sulphur to transgenic Brassica napus plants expressing the Brazil nut 2S albumin in their seeds were studied in the field. The aim was to determine if transgenic plants responded differently to such stress, and whether expression of the transgene would be effected. The transgenic plants were similar to normal plants in their response to sulphur stress. Increases in sulphur concentration were correlated with an increase in fresh and dry matter quantities as well as an increase in the carbon, nitrogen and sulphur levels in the vegetative parts of the plants. No effect on yield parameters was observed. Increasing sulphur levels resulted in an increase in the glucosinolate content, and shifts in fatty acid composition were observed. None of these changes could be correlated with the response of the transgene. The expression of the latter was altered at neither the mRNA nor the protein levels, presumably because the promoter used does not respond directly to sulphur level changes. The procedures used to create the transgenic plants in this work appear not to result in plants that respond to sulphur stress differently from normal plants in the ranges studied.