369 Manipulating dough strength in wheat by the introduction and over expression of high molecular weight glutenin gene 1Ax1: Recent progress on wheat transformation, from the lab to the field.

J. Zhao (1), S. Bean (2), P. McCluskey (2), G. Lookhart (3), H.-P. Zhou (1), W. Goure (1), F. Altpeter (4), V. Vasil (4), and I. K. VASIL (4). (1) Monsanto, St. Louis, MO 63167; (2) Dept. Grain Sci. & Ind., Kansas State Univ., Manhattan, KS 66506; (3) USDA, ARS GMPRC, Manhattan, KS 66502; (4) Lab. of Plant Cell & Mol. Biol., Univ. of Florida, Gainesville, FL 32611-0690.

Bobwhite wheat contains 6 high molecular weight glutenin genes (1Ay, Ax2, Dx5, Bx7, By9, Dy10), but only 5 are expressed, as 1Ay is always silent. We have introduced a 7th HMW-GS gene, 1Ax1, into Bobwhite and demonstrated its expression and accumulation in the endosperm. The transgenic lines expressing 1Ax1 were analyzed for stability of gene expression and their effect on food functionality. The expression of the 6th HMW-GS (1Ax1) in R4 generation plants under field growing conditions did not disrupt the expression of the 5 native HMW-GS, and was similar to that found in R2 generation plants from a growth chamber, indicating that the high level expression of 1Ax1 under its own promoter is stable. Some 1Ax1 transgenic lines had increased levels of insoluble polymeric protein (IPP), indicating that the over expressed 1Ax1 was incorporated into the large polymeric protein network. Correlations were found between IPP and dough properties: these results are consistent with the hypothesis that increasing HMW-GS level will increase dough strength and bake mix times of wheat flour.