A A C C   2 0 0 0   A n n u a l   M e e t i n g

A US wheat cultivar Triticum aestivum'Butte 86' was grown under defined regimes of temperature, water and fertilizer from anthesis until maturity and the accumulation of transcripts for the major gluten gene families was analyzed. Transcripts from all of the major gene families accumulated coordinately in developing kernels under all environmental regimes. Daytime temperatures had little effect on the amounts of gluten transcripts but altered the temporal expression of the genes. In kernels subjected to high (37°C) daytime temperatures, transcripts were first apparent by 7 DPA and were present at high levels until sometime between 30 and 34 DPA. Gluten transcripts were not detected until 8 DPA in kernels grown under cool (24°C) daytime temperatures and could still be detected at 38 DPA. The temporal regulation of the gluten transcripts was not affected by the application of post-anthesis fertilizer. In fact, under cool temperatures in the absence of post-anthesis fertilizer, the gluten mRNAs were still abundant more than 10 days after protein reached maximal levels, suggesting that under conditions of nitrogen depletion the regulation of protein accumulation is primarily at the translational level rather than at the transcriptional level. However, the amount of transcripts for certain gluten proteins, most notably the omega-gliadins, was lower in grains developing in the absence of fertilizer when compared to those supplied with ample fertilizer.