title: Deletion of the low-molecular-weight glutenin subunit allele Glu-A3a of wheat (Triticum aestivum L.) significantly reduces dough strength and breadmaking quality.
abstract: BACKGROUND
  Low-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.
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  This 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.
authors.forename: Shoumin
authors.initials: S
authors.lastname: Zhen
authors.forename: Caixia
authors.initials: C
authors.lastname: Han
authors.forename: Chaoying
authors.initials: C
authors.lastname: Ma
authors.forename: Aiqin
authors.initials: A
authors.lastname: Gu
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Xixi
authors.initials: X
authors.lastname: Shen
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Li
authors.forename: Yueming
authors.initials: Y
authors.lastname: Yan
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001939:Bread / Q000592:standards*; D002523:Edible Grain / Q000235:genetics / Q000502:physiology; D017353:Gene Deletion; D005983:Glutens / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017433:Protein Structure, Secondary; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D014908:Triticum / Q000235:genetics / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D005983:Glutens; C037302:glutenin