Asymmetric evolution and domestication in allotetraploid cotton (Gossypium hirsutum L.)  

作　　者：Lei Fang Xueying Guan Tianzhen Zhang 

机构地区：[1]State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R&D Engineering Center (the Ministry of Education),Nanjing Agricultural University, Nanjing 210095, China

出　　处：《The Crop Journal》2017年第2期159-165,共7页作物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.3133058,31290213);the Fundamental Research Funds for the Central Universities,the Priority Academic Program Development of Jiangsu Higher Education Institutions;the 111 Project(B08025)

摘　　要：Polyploidy plays a major role in genome evolution,which corresponds to environmental changes over millions of years.The mechanisms of genome evolution,particularly during the process of domestication,are of broad interest in the fields of plant science and crop breeding.Upland cotton is derived from the hybridization and polyploidization of its ancient A and D diploid ancestors.As a result,cotton is a model for polyploid genome evolution and crop domestication.To explore the genomic mysteries of allopolyploid cotton,we investigated asymmetric evolution and domestication in the A and D subgenomes.Interestingly,more structural rearrangements have been characterized in the A subgenome than in the D subgenome.Correspondingly,more transposable elements,a greater number of lost and disrupted genes,and faster evolution have been identified in the A subgenome.In contrast,the centromeric retroelement(RT-domain related) sequence of tetraploid cotton derived from the D subgenome progenitor was found to have invaded the A subgenome centromeres after allotetrapolyploid formation.Although there is no genome-wide expression bias between the subgenomes,as with expression-level alterations,gene expression bias of homoeologous gene pairs is widespread and varies from tissue to tissue.Further,there are more positively selected genes for fiber yield and quality in the A subgenome and more for stress tolerance in the D subgenome,indicating asymmetric domestication.This review highlights the asymmetric subgenomic evolution and domestication of allotetraploid cotton,providing valuable genomic resources for cotton research and enhancing our understanding of the basis of many other allopolyploids.Polyploidy plays a major role in genome evolution, which corresponds to environmental changes over millions of years. The mechanisms of genome evolution, particularly during the process of domestication, are of broad interest in the fields of plant science and crop breeding. Upland cotton is derived from the hybridization and polyploidization of its ancient A and D diploid ancestors. As a result, cotton is a model for polyploid genome evolution and crop domestication. To explore the genomic mysteries of allopolyploid cotton, we investigated asymmetric evolution and domestication in the A and D subgenomes. Interestingly, more structural rearrangements have been characterized in the A subgenome than in the D subgenome. Correspondingly, more transposable elements, a greater number of lost and disrupted genes, and faster evolution have been identified in the A subgenome. In contrast, the centromeric retroelement （RT-domain related） sequence of tetraploid cotton derived from the D subgenome progenitor was found to have invaded the A subgenome centromeres after allotetrapolyploid formation. Although there is no genome-wide expression bias between the subgenomes, as with expression-level alterations, gene expression bias of homoeologous gene pairs is widespread and varies from tissue to tissue. Further, there are more positively selected genes for fiber yield and quahty in the A subgenome and more for stress tolerance in the D subgenome, indicating asymmetric domestication. This review highlights the asymmetric subgenomic evolution and domestication of allotetraploid cotton, providing valuable genomic resources for cotton research and enhancing our understanding of the basis of many other allopolyploids.

关 键 词：POLYPLOIDY Allotetraploid cotton Asymmetric evolution Asymmetric domestication 

分 类 号：S562[农业科学—作物学]