Diversity and sub-functionalization of TaGW8 homoeologs hold potential for genetic yield improvement in wheat  

作　　者：Lin Ma Chenyang Hao Hongxia Liu Jian Hou Tian Li Xueyong Zhang 

机构地区：[1]Key Laboratory of Crop Gene Resources and Germplasm Enhancement,Ministry of Agriculture/Institute of Crop Sciences,Chinese Academy of Agricultural Sciences,Beijing 100081,China [2]Institute of Animal Sciences,Chinese Academy of Agricultural Sciences,Beijing 100193,China

出　　处：《The Crop Journal》2019年第6期830-844,共15页作物学报（英文版）

基　　金：supported by the National Key Research and Development Program of China (2016YFD0100402);the National Natural Science Foundation of China (31671687);the National Major Project for Developing New GM Crops (2016ZX08009001);Agricultural Science and Technology Innovation Program of CAAS

摘　　要：Grain Weight 8(GW8) in rice is a SQUAMOSA Promoter-Binding Protein-Like(SPL) family transcription factor with multiple biological functions. In this study, three GW8 homoeologs were cloned from homoeologous group 7 chromosomes of wheat. Subcellular localization and trans-activation activity assays suggested that Ta GW8 is a transcriptional activator.Ta GW8 genes were preferentially expressed in young spikes and developing grains. Ectopic expressions of Ta GW8 in Arabidopsis and rice resulted in enhanced vegetative growth,earlier flowering and larger seeds. Ta GW8-7 A was the most highly variable of the three homoeologs with four haplotypes(Hap-1/2/3/4). Ta GW8-7 B had two haplotypes(Hap-L/H).Ta GW8-7 A-Hap-2 was associated with high thousand-grain weight(TGW) and large kernel length and showed higher transcriptional levels and binding activity than the other haplotypes. The high frequency of Ta GW8-7 A-Hap-2 in Chinese wheat populations suggested that it had been extensively selected in breeding. This haplotype showed a high potential for exploitation in global wheat breeding because its frequency was low in exotic germplasm. Ta GW8-7 B-Hap-H produced abundant transcripts and was associated with early heading and maturity, less tiller number and high TGW. This haplotype might be suitable for multiple cropping systems due to short wheat season. In this study we identified sub-functionalization among Ta GW8 homoeologs and obtained functional molecular markers that can be used in breeding for high grain yield.Grain Weight 8(GW8) in rice is a SQUAMOSA Promoter-Binding Protein-Like(SPL) family transcription factor with multiple biological functions. In this study, three GW8 homoeologs were cloned from homoeologous group 7 chromosomes of wheat. Subcellular localization and trans-activation activity assays suggested that Ta GW8 is a transcriptional activator.Ta GW8 genes were preferentially expressed in young spikes and developing grains. Ectopic expressions of Ta GW8 in Arabidopsis and rice resulted in enhanced vegetative growth,earlier flowering and larger seeds. Ta GW8-7 A was the most highly variable of the three homoeologs with four haplotypes(Hap-1/2/3/4). Ta GW8-7 B had two haplotypes(Hap-L/H).Ta GW8-7 A-Hap-2 was associated with high thousand-grain weight(TGW) and large kernel length and showed higher transcriptional levels and binding activity than the other haplotypes. The high frequency of Ta GW8-7 A-Hap-2 in Chinese wheat populations suggested that it had been extensively selected in breeding. This haplotype showed a high potential for exploitation in global wheat breeding because its frequency was low in exotic germplasm. Ta GW8-7 B-Hap-H produced abundant transcripts and was associated with early heading and maturity, less tiller number and high TGW. This haplotype might be suitable for multiple cropping systems due to short wheat season. In this study we identified sub-functionalization among Ta GW8 homoeologs and obtained functional molecular markers that can be used in breeding for high grain yield.

关 键 词：GRAIN yield HAPLOTYPE association Marker assisted breeding Thousand GRAIN weight TRITICUM AESTIVUM 

分 类 号：S51[农业科学—作物学]