Deletion of the low-molecular-weight glutenin subunit allele Glu-A3a of wheat (Triticum aestivumL.) significantly reduces dough strength and breadmaking quality

Abstract

BackgroundLow-molecular-weight glutenin subunits (LMW-GS), encoded by Glu-3 complex loci in hexaploid wheat, play important roles in the processing quality of wheat flour. To date, the molecular characteristics and effects on dough quality of individual Glu-3 alleles and their encoding proteins have been poorly studied. We used a Glu-A3 deletion line of the Chinese Spring (CS-n) wheat variety to conduct the first comprehensive study on the molecular characteristics and functional properties of the LMW-GS allele Glu-A3a.ResultsThe Glu-A3a allele at the Glu-A3 locus in CS and its deletion in CS-n were identified and characterized by proteome and molecular marker methods. The deletion of Glu-A3a had no significant influence on plant morphological and yield traits, but significantly reduced the dough strength and breadmaking quality compared to CS. The complete sequence of the Glu-A3a allele was cloned and characterized, which was found to encode a B-subunit with longer repetitive domains and an increased number of α-helices. The Glu-A3a-encoded B-subunit showed a higher expression level and accumulation rate during grain development. These characteristics of the Glu-A3a allele could contribute to achieving superior gluten quality and demonstrate its potential application to wheat quality improvement. Furthermore, an allele-specific polymerase chain reaction (AS-PCR) marker for the Glu-A3a allele was developed and validated using different bread wheat cultivars, including near-isogenic lines (NILs) and recombinant inbred lines (RILs), which could be used as an effective molecular marker for gluten quality improvement through marker-assisted selection.ConclusionsThis work demonstrated that the LMW-GS allele Glu-A3a encodes a specific LMW-i type B-subunit that significantly affects wheat dough strength and breadmaking quality. The Glu-A3a-encoded B-subunit has a long repetitive domain and more α-helix structures as well as a higher expression level and accumulation rate during grain development, which could facilitate the formation of wheat with a stronger dough structure and superior breadmaking quality.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0367-3) contains supplementary material, which is available to authorized users.

Grain quality characteristics and dough rheological properties in Langdon durum–wild emmer wheat chromosome substitution lines under nitrogen and water deficits

“…The LDN(DIC‐1A) line showed alleles Glu‐A3a* and Glu‐B3b ; however, the LDN(DIC‐1B) line had alleles Glu‐A3b and Glu‐B3c* . Due to the considerable allelic variation observed at the Glu‐3 loci and differences in the genetic background of the plant materials, it is generally difficult to determine precisely functional properties of individual alleles in wheat genotypes . Generally, the LMW‐GS encoded by the Glu‐A3 locus have a more advantageous influence on bread‐making performance than the LMW glutenins encoded by the Glu‐B3 locus .…”

“…Generally, the LMW‐GS encoded by the Glu‐A3 locus have a more advantageous influence on bread‐making performance than the LMW glutenins encoded by the Glu‐B3 locus . According to literature data, LMW‐GS encoded by alleles Glu‐A3b and Glu‐B3b, found in LDN, have a significant effect on dough strength and bread‐making quality …”

Low‐molecular‐weight glutenin subunits from the 1U genome of Aegilops umbellulata confer superior dough rheological properties and improve breadmaking quality of bread wheat

“…The LMW B‐subunits are the most abundant among LMW‐GS in mature grains and have the greatest impact on wheat processing qualities . Recently, our study confirmed that the deletion of Glu‐A3a and Glu‐B3h , encoding abundant B‐subunits in the common wheat variety Chinese Spring and CB037C, respectively, significantly reduces dough strength and breadmaking quality, indicating the important roles of LMW B‐subunits in gluten formation. In addition, one new 1S l ‐encoded B‐subunit was highly expressed, and may make a major contribution to dough quality .…”

“…The correlations between allelic variations of Glu‐3 and breadmaking quality in common wheat are well established . Recent studies have shown that Glu‐A3a and Glu‐B3h contribute to superior flour quality . The linkage of specific LMW‐GS proteins with all Glu‐3 gene haplotypes makes it possible to discern the roles of individual LMW‐GS in wheat flour functionality and develop new lines with improved quality .…”

Low molecular weight glutenin subunit gene Glu-B3h confers superior dough strength and breadmaking quality in wheat (Triticum aestivum L.)

“…used a set of Aroona NILs of bread wheat to clarify the contribution of each allele to processing quality, and showed that alleles Glu-A3b, Glu-A3d, Glu-B3g , and Glu-B3f make significant contributions to mixograph properties. More recently, Zhen et al 22. used a natural mutation at the Glu-A3 locus to study the function of the Glu-A3a allele in bread wheat, and found that Glu-A3a significantly affects dough strength and breadmaking quality.…”