New insights into the organization, recombination, expression and functional mechanism of low molecular weight glutenin subunit genes in bread wheat.
The bread-making quality of wheat is strongly influenced by multiple low molecular weight glutenin subunit (LMW-GS) proteins expressed in the seeds. However, the organization, recombination and expression of LMW-GS genes and their functional mechanism in bread-making are not well understood. Here we report a systematic molecular analysis of LMW-GS genes located at the orthologous Glu-3 loci (Glu-A3, B3 and D3) of bread wheat using complementary approaches (genome wide characterization of gene members, expression profiling, proteomic analysis). Fourteen unique LMW-GS genes were identified for Xiaoyan 54 (with superior bread-making quality). Molecular mapping and recombination analyses revealed that the three Glu-3 loci of Xiaoyan 54 harbored dissimilar numbers of LMW-GS genes and covered different genetic distances. The number of expressed LMW-GS in the seeds was higher in Xiaoyan 54 than in Jing 411 (with relatively poor bread-making quality). This correlated with the finding of higher numbers of active LMW-GS genes at the A3 and D3 loci in Xiaoyan 54. Association analysis using recombinant inbred lines suggested that positive interactions, conferred by genetic combinations of the Glu-3 locus alleles with more numerous active LMW-GS genes, were generally important for the recombinant progenies to attain high Zeleny sedimentation value (ZSV), an important indicator of bread-making quality. A higher number of active LMW-GS genes tended to lead to a more elevated ZSV, although this tendency was influenced by genetic background. This work provides substantial new insights into the genomic organization and expression of LMW-GS genes, and molecular genetic evidence suggesting that these genes contribute quantitatively to bread-making quality in hexaploid wheat. Our analysis also indicates that selection for high numbers of active LMW-GS genes can be used for improvement of bread-making quality in wheat breeding.
Dong
Lingli
L
State Key Laboratory of Plant Cell and Chromosome Engineering, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
Zhang
Xiaofei
X
Liu
Dongcheng
D
Fan
Huajie
H
Sun
Jiazhu
J
Zhang
Zhongjuan
Z
Qin
Huanju
H
Li
Bin
B
Hao
Shanting
S
Li
Zhensheng
Z
Wang
Daowen
D
Zhang
Aimin
A
Ling
Hong-Qing
HQ
D000483:Alleles; D000595:Amino Acid Sequence; D022202:Chromosomes, Artificial, Bacterial; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D005983:Glutens / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014908:Triticum / Q000235:genetics*
D005983:Glutens; C037302:glutenin