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Nature Genetics：草棉、亚洲棉及陆地棉基因组揭示棉花A基因组演化

已有 3846 次阅读 2020-4-21 08:05 |个人分类:每日摘要|系统分类:论文交流

**Genome sequence of Gossypium herbaceum and genome updates of Gossypium arboreum and Gossypium hirsutum provide insights into cotton A-genome evolution**

First author: Gai Huang; Affiliations: Wuhan University (武汉大学): Wuhan, China

Corresponding author: Yuxian Zhu

Upon assembling the first Gossypium herbaceum (A1) genome and substantially improving the existing Gossypium arboreum (A2) and Gossypium hirsutum ((AD)1) genomes, we showed that all existing A-genomes may have originated from a common ancestor, referred to here as A0, which was more phylogenetically related to A1 than A2. Further, allotetraploid formation was shown to have preceded the speciation of A1 and A2. Both A-genomes evolved independently, with no ancestor–progeny relationship. Gaussian probability density function analysis indicates that several long-terminal-repeat bursts that occurred from 5.7 million years ago to less than 0.61 million years ago contributed compellingly to A-genome size expansion, speciation and evolution. Abundant species-specific structural variations in genic regions changed the expression of many important genes, which may have led to fiber cell improvement in (AD)1. Our findings resolve existing controversial concepts surrounding A-genome origins and provide valuable genomic resources for cotton genetic improvement.

通过首次报道草棉（Gossypium herbaceum，A1基因组）的基因组以及对亚洲棉（Gossypium arboreum，A2基因组）和陆地棉（Gossypium hirsutum，(AD)1基因组）的基因组组装改良提升，作者发现现存的所有A基因组可能都起源于一个共同的祖先，这里作者将其定义为A0基因组，该基因组在系统发育上相比于A2，更加靠近A1。此外，棉花异源四倍体的形成要早于A1和A2基因组的特化。这两个A基因组都相互独立地演化，相互之间并不存在祖先与子代的关系。高斯概率密度函数分析显示从五百七十万年前到六十一万年前，这个期间长末端LTR重复序列的几次爆发作用于A基因组的扩张、特化和演化。基因区丰富的物种特异性结构变异改变了许多重要基因的表达，这可能导致了(AD)1基因组物种中纤维细胞的提升。本文的发现解决了现在围绕棉花A基因组起源的争论，并为棉花的遗传改良提供了宝贵的遗传资源。