转座元件对植物基因组进化、表观遗传和适应性的作用  

Roles of transposable elements on plant genome evolution,epigenetics and adaptation

作　　者：顾小琳 苏应娟[2,3] 王艇 Xiaolin Gu;Yingjuan Su;Ting Wang(Collge of Life Ciences,South China Agricultural Universiy,Guangzhou 510642,China;School of Life Sciences,Sun Yat-sen Universiny,Guangzhou 510275,China;Research Insituteof Sun Yat-sen University in Shenzhen,Shenzhen 518057,China)

机构地区：[1]华南农业大学生命科学学院,广州510642 [2]中山大学生命科学学院,广州510275 [3]中山大学深圳研究院,深圳518057

出　　处：《科学通报》2022年第25期3024-3035,共12页Chinese Science Bulletin

基　　金：国家自然科学基金(31670200,31770587,31872670,32071781)资助。

摘　　要：转座元件是基因组内可移动的DNA序列,其结构和转座机制具有广泛的多样性.转座元件普遍存在于植物基因组中,特别是反转录转座子.转座元件的扩增、插入可能会改变宿主原本基因组的稳定性,因此宿主进化出了各种沉默机制防御转座元件的转座.随着对转座元件研究的不断深入,越来越多的证据表明,转座元件的插入所带来的并不完全是破坏,它们可能是基因组多样性的驱动力,甚至在作物驯化方面起重要作用.另外,转座元件与宿主之间可能相互影响,尤其是在环境胁迫条件下.本文概述了植物基因组转座元件的相关研究,介绍了植物中常见的转座元件,并探讨了转座元件在植物基因组进化、表观遗传调控中发挥的作用以及在环境胁迫下转座元件与宿主之间存在的合作关系.Transposable elements(TEs) are mobile DNA sequences within the genome, and their structure and transposition mechanism are highly diverse. TEs can be divided into retrotransposons(RTs;Class I) and DNA transposons(Class II),depending on whether their transposition intermediate is RNA or DNA. RTs transpose in a “copy-and-paste” manner and are therefore considered to be an essential contributor during genome expansion. RTs can be further divided into long terminal repeat retrotransposons(LTR-RTs) and non-long terminal repeat retrotransposons(non-LTR-RTs). Copia and Gypsy are two superfamilies of LTR-RTs commonly found in plant genomes, and their structural differences lie in the INT positions in the internal sequence of the pol open reading frame(ORF). Non-LTR-RTs include long interspersed nuclear elements(LINEs) and short interspersed nuclear elements(SINEs), which lack LTRs and usually have poly(A) or simple repeats at their 3′ end. DNA transposons directly cut the DNA sequence at the original site by transposase and insert a new site, similar to “cut-and-paste”. Insertion of DNA transposons into new sites results in target site duplications(TSDs), and DNA strand breaks due to transposition are repaired by DNA repair mechanisms. DNA transposons in plants can be further divided into “cut-and-paste” transposons and Helitrons with the “rolling circle” transposition pattern.TEs play an important role in genome evolution. In the process of their insertion, deletion, and amplification, the host may alter its genome size, gene expression, and gene function. Additionally, TEs may mediate chromosomal rearrangements through homologous recombination or alternative transposition. Overall, TEs are very powerful mutagens that can affect the stability of their host genomes. In order to defend against the transposition of TEs, the host has evolved various silencing mechanisms. In plants, the silencing of TEs is mainly established through RNA-directed DNA methylation(Rd DM), which can stably repress the activity

关 键 词：转座元件 基因组进化 表观遗传 环境胁迫 适应性 

分 类 号：Q943[生物学—植物学]