ENGINEERING CHANGES IN WHEAT-FLOUR BY GENETIC-TRANSFORMATION

The strength and elasticity of doughs made from wheat (Triticum aestiv um) flours have been correlated to their content of high-molecular-wei ght glutenin subunits (HMW-GS). The development of a reliable method f or genetic transformation has enabled us to make directed modification s in the amounts and composition of these storage proteins by adding g enes to wheat that encode a modified HMW-GS. A number of transgenic wh eat lines have been obtained in which the accumulation of the introduc ed gene product is additive to that of the endogenous HMW-GS. However, in one line, addition of HMW-GS genes resulted in partial suppression of endogenous subunit accumulation. Patterns of transgene expression have been stable in homozygous derivatives of these lines for as many as seven generations of growth in the greenhouse. The ability to chang e the levels and composition of the HMW-GS of wheat seeds by genetic e ngineering raises the possibility of tailoring flour properties to end -user specifications of dough strength.