A Study of Puroindoline b Gene Involvement in the Milling Behavior of Hard‐Type Common Wheats

Abstract

Differences in milling behavior among hard‐type common wheat (Triticum aestivum) cultivars are well known to millers. Among them, the French cultivar Soissons, which contains the Pinb‐D1d allelic form of the puroindoline b gene, is particularly distinguished for its high milling value. Near‐isogenic lines (NILs) differing by the allelic forms of the puroindoline b gene, Pinb‐D1d or Pinb‐D1b (one of the most frequent alleles found in the European wheat population), were constructed. Grain characteristics obtained after wheat cultivation in distinct environmental conditions were compared between NILs and the cultivar Soissons, as was their fractionation behavior. Results showed that NILs containing the Pinb‐D1d allele displayed lower values of grain hardness and vitreousness than did the corresponding lines containing the Pinb‐D1b allelic form under the same cultivation conditions. Both genetic background and environmental conditions appeared to affect grain texture. Measured single‐kernel characterization system hardness index values of the samples under study were found to be correlated with the vitreousness values. Studies of the milling behavior helped to point out that grain vitreousness is an important factor acting on endosperm breakage ability, whatever the genetic background of the wheat. Our results also demonstrated that, at similar levels of vitreousness, the endosperm of Soissons could more easily be reduced than that of other wheat lines.

Toward the Genetic Basis and Multiple QTLs of Kernel Hardness in Wheat

“…In one example, Tsilo et al identified a QTL linked to chr. 5DS using a bi-parental population in which the two parents both had an identical Pin genotype and the hard-kernel phenotype, indicating that another gene, likely closely linked to the Ha locus, may be responsible for the phenotypic variation [89]. Recently, a transgenic study of GSP on the Ha locus showed that regulation of GSP can have a small effect on grain hardness, coinciding with the minor QTL detected on chr.…”

“…Numerous studies have been focused on mining allelic variations and the genotype-phenotype association of Pin, resulting in the identification of 26 alleles of Pina, 33 alleles of Pinb and a few double null alleles [21,22,[77][78][79][80][81][82][83][84][85][86][87]. Manipulation of the expression or genotypes of Pin not only modifies kernel hardness and milling properties in common and durum wheat lines [62][63][64]67,[88][89][90][91][92], but also changes some parameters of the end-use quality and storage protein interaction [29,[93][94][95]. Owing to its importance, research regarding Pin has been comprehensively reviewed by Bhave et al [21,22] in aspects of its genetics, polymorphism identification and studies about its biological functions.…”

Mutagenesis‐Derived Puroindoline Alleles in Triticum aestivum and Their Impacts on Milling and Bread Quality

“…Grain hardness changes conditioned by puroindolines are positively correlated with flour yield and negatively correlated with break flour yield (Campbell et al 2001;Martin et al 2001Martin et al , 2007Hogg et al 2005;Reynolds et al 2010aReynolds et al , 2010b. Even small changes in grain hardness such as the 5-10 units that separate seeds carrying different Pin alleles common in hard wheats are enough to significantly modify milling and baking properties (Martin et al 2001;Ma et al 2009;Takata et al 2010;Lasme et al 2012). It is therefore to be expected that generating novel puroindoline alleles with unique hardness levels would expand the range in milling traits, some of which should give improved performance over common Pin alleles.…”

Biomechanical properties of wheat grains: the implications on milling

“…In wheat cultivars, this texture trait is determined by the Puroindoline a ( Pina ) and Puroindoline b ( Pinb ) gene alleles at the Hardness locus ( Ha ) [ 5 ]. Although the genetic determinants that distinguish soft and hard wheat are known [ 30 , 31 ], what is known in less detail is the relationship between the genes and the biochemical and biomechanical basis for the grain hardness differences. Soft and hard wheat starchy endosperms differ in their puroindoline a (PINA) and b (PINB) protein contents, but how this translates into defined biomechanical differences that underpin the distinct milling and flour properties is still unclear.…”