|A glycine to serine change in Puroindoline b is associated with wheat grain hardness and low levels of starch-surface Friabilin. Theoretical and Applied Genetics 95:857-864
|Giroux,M.J. and Morris,C.F.
USDA/ARS Western Wheat Quality Lab
|The quantitative level of friabilin
15-kDa protein present in the surface of water-washed starch is highly correlated
with wheat grain softness. Friabilin is composed primarily, if not exclusively,
of the proteins puroindoline a and b. The transcript levels of these two proteins
are similar among hard and soft wheat varieties, and the expression of both
is controlled by the short arm of chromosome 5D, also the chromosomal location
of the Hardness gene. We report here a glycine to serine sequence change in
puroindoline-b mutation, hard grain texture and low levels of starch surface
friabilin lines derived from the soft-textured variety 'Chinese Spring' and
the substitution line 'Chinese Spring' containing the 5D chromosome of the hard-textures
variety 'Cheyenne'. The sequence change reported here may adversely affect the
lipid-binding properties of puroindoline-b and so effect hard grain texture.
The results from puroindoline-b functionality such that the Hardness gene is
a direct manifestation of puroindoline structure. We are suggesting the tentative
molecular structure. We are suggesting the tentative molecular marker loci designations
of Pinb-D1a and Pinb-D1b for the glycine and serine puroindoline-b types, respectively.
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