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Mechanisms, origin and heredity of Glu-1Ay silencing in wheat evolution and domestication
- Luo, Guangbin, Song, Shuyi, Zhao, Liru, Shen, Lisha, Song, Yanhong, Wang, Xin, Yu, Kang, Liu, Zhiyong, Li, Yiwen, Yang, Wenlong, Li, Xin, Zhan, Kehui, Zhang, Aimin, Liu, Dongcheng
- Theoretical and applied genetics 2018 v.131 no.7 pp. 1561-1575
- Triticum aestivum, Triticum monococcum subsp. aegilopoides, Triticum monococcum subsp. monococcum, Triticum urartu, alleles, diploidy, domestication, evolution, glutenins, hexaploidy, inheritance (genetics), progeny, retrotransposons, stop codon, tetraploidy, wheat
- KEY MESSAGE: Allotetraploidization drives Glu-1Ay silencing in polyploid wheat. The high-molecular-weight glutenin subunit gene, Glu-1Ay, is always silenced in common wheat via elusive mechanisms. To investigate its silencing and heredity during wheat polyploidization and domestication, the Glu-1Ay gene was characterized in 1246 accessions containing diploid and polyploid wheat worldwide. Eight expressed Glu-1Ay alleles (in 71.81% accessions) and five silenced alleles with a premature termination codon (PTC) were identified in Triticum urartu; 4 expressed alleles (in 41.21% accessions), 13 alleles with PTCs and 1 allele with a WIS 2-1A retrotransposon were present in wild tetraploid wheat; and only silenced alleles with PTC or WIS 2-1A were in cultivated tetra- and hexaploid wheat. Both the PTC number and position in T. urartu Glu-1Ay alleles (one in the N-terminal region) differed from its progeny wild tetraploid wheat (1–5 PTCs mainly in the repetitive domain). The WIS 2-1A insertion occurred ~ 0.13 million years ago in wild tetraploid wheat, much later than the allotetraploidization event. The Glu-1Ay alleles with PTCs or WIS 2-1A that arose in wild tetraploid wheat were fully succeeded to cultivated tetraploid and hexaploid wheat. In addition, the Glu-1Ay gene in wild einkorn inherited to cultivated einkorn. Our data demonstrated that the silencing of Glu-1Ay in tetraploid and hexaploid wheat was attributed to the new PTCs and WIS 2-1A insertion in wild tetraploid wheat, and most silenced alleles were delivered to the cultivated tetraploid and hexaploid wheat, providing a clear evolutionary history of the Glu-1Ay gene in the wheat polyploidization and domestication processes.