Environmental Conditions During Wheat Grain Development Alter Temporal Regulation of Major Gluten Protein Genes

Abstract

The accumulation of transcripts for the major gluten storage proteins was assessed during grain development in wheat plants (Triticum aestivum L. ‘Butte 86’) grown under seven controlled environments where temperature, water, and fertilizer conditions were varied after anthesis. Transcripts within the α‐, γ‐ and ω‐gliadin, low molecular weight glutenin subunit (LMW‐GS), and high molecular weight glutenin subunit (HMW‐GS) gene families followed similar patterns of accumulation throughout grain development under each environmental regimen. Under moderate daytime temperatures in plants that were well watered and fertilized, transcripts from all gene families were detectable by eight days postanthesis (8 DPA), were present at high levels until ≈34 DPA, and disappeared between 36 and 38 DPA. Under high temperature regimens, transcripts from all gene families appeared slightly earlier, but the time frame of accumulation was shorter. The presence or absence of postanthesis fertilizer did not alter the temporal regulation of the gluten genes under the moderate temperature regimen. However, under the high daytime temperature regimen, transcripts disappeared slightly earlier in kernels from plants that did not receive postanthesis fertilizer. Reverse transcriptase polymerase chain reaction (RT‐PCR) using primer pairs for specific HMW‐GS and LMW‐GS transcripts revealed that individual genes within each family exhibited identical patterns of temporal regulation under different environmental conditions.

Protein content and gluten quality of durum wheat (Triticum turgidum subsp. durum) as affected by sowing date

“…In contrast to the high sensitivity of gliadins to high temperature as reported in the literature, 14,16,29 the gliadin percentage of our materials remained almost constant, while the glutenin percentage increased as the sowing date was delayed. Given that glutenins contribute heavily to the strength and elasticity of dough, 12 an increase in their contribution to overall gluten content would be expected to have had a positive effect on W .…”

“…10,11 Of the two major components of gluten, the gliadins contribute to dough extensibility, while the glutenins contribute to dough strength and elasticity. 12 The differential effect of high temperature on gliadin and glutenin synthesis, resulting in a relatively higher production of gliadins and hence to reduced dough strength, has been frequently noted. 13 -17 In particular, extensive variation with respect to both the size and direction of change of the gliadin to glutenin ratio has been observed in a survey of 75 bread and durum wheat cultivars exposed to short periods of high temperature under controlled conditions.…”

Identification and characterization of high temperature stress responsive genes in bread wheat (Triticum aestivum L.) and their regulation at various stages of development

“…It has long been known that average wheat yield reduces by 4% for every one degree rise in ambient temperature during grain filling (McDonald et al 1983). High temperature drastically reduces both yield and quality of wheat (Wardlaw et al 2002;Altenbach et al 2002Altenbach et al , 2003Dupont et al 2006). Heat stress induce decrease in the duration of developmental phases leading to fewer organs, smaller organs, reduced light perception over the shortened life cycle and perturbation of the processes related to carbon assimilation (transpiration, photosynthesis and respiration) are significant contributing to losses of yield (Stone 2001;Rane and Chauhan 2002;Hussain and Mudasser 2007).…”

Large-scale chromatin decondensation induced in a developmentally activated transgene locus

“…One of the six genes is always silenced, and cultivated wheat expresses three to five genes, depending on the variety (Shewry et al, 2003). The HMW subunits are activated about 8 days post anthesis (dpa) and the transcripts disappear between 36 dpa and 38 dpa (Altenbach et al, 2002). Previously, wheat genomic clones encoding the HMW glutenin subunits 1Ax1 and 1Dx5 (GenBank accession numbers: glu-1Ax1, X61009;glu-1D-1b, X12928; the genes will be referred to hereafter as 1Ax1 and 1Dx5), together with their promoter regions, had been introduced into the commercial wheat cultivar Federal, which expresses the endogenous subunits 1Ax2*, 1Bx7, 1By9, 1Dx5 and 1Dy10.…”