Omega gliadin genes expressed in Triticum aestivum cv. Butte 86: Effects of post-anthesis fertilizer on transcript accumulation during grain development

The partial coding sequences of omega gliadin genes expressed in developing wheat kernels Triticum aestivum cv. Butte 86 were identified in databases of expressed sequence tags (ESTs). Three gene assemblies encode proteins with PQQPFP as the predominant repetitive motif. Of these, two encode proteins with at least one cysteine and thus may be incorporated into the glutenin polymer. Another two gene assemblies encode proteins with FPQQQ and QQIPQQ repeats. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) was used to investigate the accumulation of omega gliadin transcripts in developing wheat grains produced with or without post-anthesis fertilizer supplied as 20–20–20 nitrogen–phosphorous–potassium (NPK). Omega gliadin transcripts were detected at 8 days post-anthesis (DPA). The levels of transcript changed little in the absence of NPK during grain development, but increased when plants were supplied with post-anthesis NPK. By 32 DPA, levels of omega gliadin transcripts were considerably higher in grains that received NPK than in those that did not receive NPK. Transcripts for a gamma gliadin showed a different profile, increasing from 8 to about 22 DPA, then decreasing at later time points. In contrast to omega gliadins, both the timing and levels of gamma gliadin transcripts were similar in grains produced with or without post-anthesis NPK.