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Silencing of omega-5 gliadins in transgenic wheat eliminates a major source of environmental variability and improves dough mixing properties of flour.

Altenbach SB, Tanaka CK, Seabourn BW - BMC Plant Biol. (2014)

Bottom Line: In one transgenic line, all 2-DE spots identified as omega-5 gliadins were substantially reduced without effects on other proteins.The data indicate that omega-5 gliadins have a negative effect on flour quality and suggest that changes in quality with the growth environment may be due in part to alterations in the levels of the omega gliadins.Because a known food allergen and one of the major sources of environmentally-induced variation in wheat flour protein composition has been eliminated, the transgenic lines may yield flour with both improved end-use quality and more consistent functionality when grown in different locations.

View Article: PubMed Central - PubMed

Affiliation: USDA-ARS, Western Regional Research Center, 800 Buchanan Street, Albany, CA, 94710, USA. susan.altenbach@ars.usda.gov.

ABSTRACT

Background: The end-use quality of wheat flour varies as a result of the growth conditions of the plant. Among the wheat gluten proteins, the omega-5 gliadins have been identified as a major source of environmental variability, increasing in proportion in grain from plants that receive fertilizer or are subjected to high temperatures during grain development. The omega-5 gliadins also have been associated with the food allergy wheat-dependent exercise-induced anaphylaxis (WDEIA). Recently, transgenic lines with reduced levels of omega-5 gliadins were developed using RNA interference (RNAi). These lines make it possible to determine whether changes in the levels of omega-5 gliadins in response to environmental conditions and agronomic inputs may be responsible for changes in flour end-use quality.

Results: Two transgenic wheat lines and a non-transgenic control were grown under a controlled temperature regimen with or without post-anthesis fertilizer and the protein composition of the resulting flour was analyzed by quantitative two-dimensional gel electrophoresis (2-DE). In one transgenic line, all 2-DE spots identified as omega-5 gliadins were substantially reduced without effects on other proteins. In the other transgenic line, the omega-5 gliadins were absent and there was a partial reduction in the levels of the omega-1,2 gliadins and the omega-1,2 chain-terminating gliadins as well as small changes in several other proteins. With the exception of the omega gliadins, the non-transgenic control and the transgenic plants showed similar responses to the fertilizer treatment. Protein contents of flour were determined by the fertilizer regimen and were similar in control and transgenic samples produced under each regimen while both mixing time and mixing tolerance were improved in flour from transgenic lines when plants received post-anthesis fertilizer.

Conclusions: The data indicate that omega-5 gliadins have a negative effect on flour quality and suggest that changes in quality with the growth environment may be due in part to alterations in the levels of the omega gliadins. Because a known food allergen and one of the major sources of environmentally-induced variation in wheat flour protein composition has been eliminated, the transgenic lines may yield flour with both improved end-use quality and more consistent functionality when grown in different locations.

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Average normalized spot volumes of omega gliadins in flour from non-transgenic and transgenic lines grown under different fertilizer regimens. For each class of proteins, the solid bars denote flour from plants grown without fertilizer while the stippled bars denote flour from plants supplied with post-anthesis fertilizer. Blue bars represent the non-transgenic control while red and green bars represent transgenic lines 35b and 45a, respectively. Total omega gliadins include the omega-5 gliadins, omega-1,2 gliadins and secalin-like omega gliadins, but not the omega-1,2 chain-terminating gliadins.
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Fig2: Average normalized spot volumes of omega gliadins in flour from non-transgenic and transgenic lines grown under different fertilizer regimens. For each class of proteins, the solid bars denote flour from plants grown without fertilizer while the stippled bars denote flour from plants supplied with post-anthesis fertilizer. Blue bars represent the non-transgenic control while red and green bars represent transgenic lines 35b and 45a, respectively. Total omega gliadins include the omega-5 gliadins, omega-1,2 gliadins and secalin-like omega gliadins, but not the omega-1,2 chain-terminating gliadins.

Mentions: Volumes of individual 2-DE spots determined from each of the technical replicate gels were averaged and the average spot volumes were then determined for the biological replicates (Additional file 2). These values were summed for all spots previously identified as the same protein by tandem mass spectrometry [6] (Table 1). Accumulation of total omega gliadins, omega-5 gliadins, omega-1,2 gliadins, and omega-1,2 chain-terminating gliadins in flour from each of the lines produced under the two fertilizer regimens is summarized in Figure 2.Table 1


Silencing of omega-5 gliadins in transgenic wheat eliminates a major source of environmental variability and improves dough mixing properties of flour.

Altenbach SB, Tanaka CK, Seabourn BW - BMC Plant Biol. (2014)

Average normalized spot volumes of omega gliadins in flour from non-transgenic and transgenic lines grown under different fertilizer regimens. For each class of proteins, the solid bars denote flour from plants grown without fertilizer while the stippled bars denote flour from plants supplied with post-anthesis fertilizer. Blue bars represent the non-transgenic control while red and green bars represent transgenic lines 35b and 45a, respectively. Total omega gliadins include the omega-5 gliadins, omega-1,2 gliadins and secalin-like omega gliadins, but not the omega-1,2 chain-terminating gliadins.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4307166&req=5

Fig2: Average normalized spot volumes of omega gliadins in flour from non-transgenic and transgenic lines grown under different fertilizer regimens. For each class of proteins, the solid bars denote flour from plants grown without fertilizer while the stippled bars denote flour from plants supplied with post-anthesis fertilizer. Blue bars represent the non-transgenic control while red and green bars represent transgenic lines 35b and 45a, respectively. Total omega gliadins include the omega-5 gliadins, omega-1,2 gliadins and secalin-like omega gliadins, but not the omega-1,2 chain-terminating gliadins.
Mentions: Volumes of individual 2-DE spots determined from each of the technical replicate gels were averaged and the average spot volumes were then determined for the biological replicates (Additional file 2). These values were summed for all spots previously identified as the same protein by tandem mass spectrometry [6] (Table 1). Accumulation of total omega gliadins, omega-5 gliadins, omega-1,2 gliadins, and omega-1,2 chain-terminating gliadins in flour from each of the lines produced under the two fertilizer regimens is summarized in Figure 2.Table 1

Bottom Line: In one transgenic line, all 2-DE spots identified as omega-5 gliadins were substantially reduced without effects on other proteins.The data indicate that omega-5 gliadins have a negative effect on flour quality and suggest that changes in quality with the growth environment may be due in part to alterations in the levels of the omega gliadins.Because a known food allergen and one of the major sources of environmentally-induced variation in wheat flour protein composition has been eliminated, the transgenic lines may yield flour with both improved end-use quality and more consistent functionality when grown in different locations.

View Article: PubMed Central - PubMed

Affiliation: USDA-ARS, Western Regional Research Center, 800 Buchanan Street, Albany, CA, 94710, USA. susan.altenbach@ars.usda.gov.

ABSTRACT

Background: The end-use quality of wheat flour varies as a result of the growth conditions of the plant. Among the wheat gluten proteins, the omega-5 gliadins have been identified as a major source of environmental variability, increasing in proportion in grain from plants that receive fertilizer or are subjected to high temperatures during grain development. The omega-5 gliadins also have been associated with the food allergy wheat-dependent exercise-induced anaphylaxis (WDEIA). Recently, transgenic lines with reduced levels of omega-5 gliadins were developed using RNA interference (RNAi). These lines make it possible to determine whether changes in the levels of omega-5 gliadins in response to environmental conditions and agronomic inputs may be responsible for changes in flour end-use quality.

Results: Two transgenic wheat lines and a non-transgenic control were grown under a controlled temperature regimen with or without post-anthesis fertilizer and the protein composition of the resulting flour was analyzed by quantitative two-dimensional gel electrophoresis (2-DE). In one transgenic line, all 2-DE spots identified as omega-5 gliadins were substantially reduced without effects on other proteins. In the other transgenic line, the omega-5 gliadins were absent and there was a partial reduction in the levels of the omega-1,2 gliadins and the omega-1,2 chain-terminating gliadins as well as small changes in several other proteins. With the exception of the omega gliadins, the non-transgenic control and the transgenic plants showed similar responses to the fertilizer treatment. Protein contents of flour were determined by the fertilizer regimen and were similar in control and transgenic samples produced under each regimen while both mixing time and mixing tolerance were improved in flour from transgenic lines when plants received post-anthesis fertilizer.

Conclusions: The data indicate that omega-5 gliadins have a negative effect on flour quality and suggest that changes in quality with the growth environment may be due in part to alterations in the levels of the omega gliadins. Because a known food allergen and one of the major sources of environmentally-induced variation in wheat flour protein composition has been eliminated, the transgenic lines may yield flour with both improved end-use quality and more consistent functionality when grown in different locations.

Show MeSH
Related in: MedlinePlus