|Finnie, Sean -|
|Jeannotte, R -|
|Giroux, Michael -|
|Faubion, J -|
Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 8, 2009
Publication Date: January 13, 2010
Repository URL: http://hdl.handle.net/10113/38253
Citation: Finnie, S.M., Jeannotte, R., Morris, C.F., Giroux, M.J., Faubion, J.M. 2010. Variation in polar lipid composition within near-isogenic wheat lines containing different puroindoline haplotypes. Journal of Cereal Science. 51:66-72. Interpretive Summary: This research paper establishes connections between the polar lipid compositions of samples containing different puroindolines by use of five near-isogenic wheat lines. The results show that endosperm hardness is a three-way interaction between the starch granule surface, puroindoline proteins, and polar lipids. Endosperm hardness had no effect on the polar lipid contents in wheat flour, had a slight influence on the polar lipid contents of the whole-meal fractions, and had a significant influence on the polar lipid composition of the polar lipids located on the surface of wheat starch. The greatest quantities of polar lipids on the starch surface occurred when both puroindoline proteins where present in their wild-type form.
Technical Abstract: An extensive amount of research has investigated kernel hardness. However, the exact mechanism underlying this phenomenon is unknown. Puroindoline-A and puroindoline-B proteins must be present in their wild-type form to create soft textured wheat. Similar to puroindoline proteins, polar lipids are present on the surface of starch granules. The objective of this research was to determine the specific polar lipid species present on the surface of wheat starch from near-isogenic wheat lines that contain different puroindoline haplotypes and endosperm hardness. Five near-isogenic wheat lines were used in this study, all derived from the soft cultivar Alpowa. Water-washed starch was isolated using a modified batter method. Direct infusion tandem mass spectrometry was used to identify the lipid species in both the flour and starch samples. Endosperm hardness had no significant effect on the polar lipid contents in wheat flour, had a slight influence on the polar lipid contents of the whole-meal, and had a significant influence on the polar lipid composition of the polar lipids located on the surface of wheat starch. The greatest quantities of polar lipids on the starch surface occurred when both puroindoline proteins where present in their wild-type form. Starch surface polar lipid content dramatically decreased when one of the puroindoline proteins were null, or if the PIN-B was in the mutated form (Trp-44 to Arg). Within the hard textured samples, more polar lipids were present on the starch surface when PIN-B was in its wild-type form and PIN-A was null than when PIN-A was in its wild-type form and PIN-B was null; the least amount of polar lipids where present when PIN-B was in its mutated form (Trp-44 to Arg) and PIN-A as in its wild-type form.