The Study Revealed The Evolutionary Divergence Of Cotton Allotetraploid Repetitive Genome

Recently, Liu Fang, a researcher at the Institute of cotton research / State Key Laboratory of cotton biology, Chinese Academy of Agricultural Sciences, and several research institutions at home and abroad, have explored the polyploidization, adaptive evolution and domestication of tetraploid cotton species at the genome-wide level, revealing the genetic variation basis of polyploidy and artificial domestication of cotton, It provides theoretical basis for polyploidization of other crops and important germplasm resources for cotton breeding innovation. The results were published online in proceedings of the National Academy of Sciences (PNAs).

Polyploidy is an important mechanism of plant evolution, which makes polyploid plants have wide adaptability. The common polyploid plants are hexaploid wheat, tetraploid cotton and potato. Allotetraploid cotton includes seven cotton species, i.e. upland cotton, island cotton, wool cotton, yellow brown cotton, Darwinian cotton, aikeman cotton and stephensi cotton. The genome sequences of the first five allotetraploid cotton species have been published, but the genome map of the newly discovered and named wild cotton, e.g. The analysis of genome information of aikeman and Stephens marks the completion of the evolutionary jigsaw of allotetraploid cotton, which is of great significance for the analysis of polyploidy and evolutionary mechanism of cotton.

In this paper, we analyzed the structure and evolution of a new cotton line named Stephania. Based on phenotypic differentiation, genetic isolation and genetic convergence of tetraploid cotton species, the genetic basis of cotton biodiversity and cotton domestication was elaborated. It was found that wild cotton had strong gene penetration in the adaptability of domesticated cotton species.

Further studies showed that the variation of gene structure encoding phosphopeptide binding protein during cotton domestication may be related to fiber length δ Isomerase 3 and ethylene response factor rap2-7 may improve abiotic stress tolerance of cotton by regulating plant hormone related biochemical pathways.

The results of this study filled the gap in the phylogenetic study of polyploid cotton, revealed the adaptive evolution mechanism of polyploid cotton, and provided valuable genetic materials for genetic improvement of cotton resistance and fiber quality.

The research was supported by NSFC and other projects. Peng Renhai is the first author of the paper and Liu Fang is the chief corresponding author. Beijing Nuohe Zhiyuan Technology Co., Ltd., Iowa State University and other institutions participated in the research.