| Occurrence of Puroindoline Alleles in Chinese Winter Wheats Cereal Chemistry 82:38-43 |
| Xia,L.,Chen,F.,He,Z.,Chen,X.,Morris,C.F. |
| Grain hardness is one of the most important characters that determine
the end-use quality of bread wheat (Triticum aestivum L.). Mutations in
genes encoding either puroindoline a (Pina) or b (Pinb) have been
associated with hard grain texture, i.e., Pina null at Pina-D1 or seven
mutations at Pinb-D1. In this study, the diversity of puroindoline alleles
in 251 Chinese winter wheat cultivars and advanced lines from four major
autumn-planted wheat regions were investigated. Among the examined
cultivars, 79 were classified as soft, while 53 were mixed in hardness, and
119 were uniformly hard. Of these hard winter wheats, three of the seven
reported mutation types were observed, with Pina-D1a/Pinb-D1b being
the dominant type for hard texture; 91 genotypes carried this allele. Sixteen
genotypes had the Pina-D1b allele, and two genotypes had the Pinb-
D1d allele. A new mutation, designated as Pinb-D1p, was detected in 10
hard genotypes, with a single nucleotide (A) deletion corresponding to
position 42 in the amino acid sequence of puroindoline b, involving a
lysine (K) to asparagine (N) change, and leading to a shift in the open reading
frame (ORF). This deletion disrupts the last part of the tryptophanrich
domain, changing it from KWWK to NGGR, which is considered
essential for the lipid-binding activity of this protein, and results in a stop
codon corresponding to position Pro-60 in the amino acid sequence. The
characterization of different hardness alleles provides useful information
in understanding the mechanism underlying the formation of endosperm
hardness while providing breeders the means of manipulating this important
trait.
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