植物非整倍体研究进展

Advances of aneuploidy in plant

关键词:  非整倍体, 剂量效应, 高通测序, 遗传改良, 基因重组, 表观遗传

Key words:  aneuploidy, gene-dosage, high throughput technology, genetic improvement, genetic recombination, epigenetic

摘要:

非整倍体(aneuploid)是指相对于正常个体(euploid)的染色体组增加、减少一条或若干条染色体的生物个体。由于非整倍体个体存在基因剂量效应的不平衡性(gene-dosage imbalance),非整倍体个体往往会表现严重的表型缺陷(aneuploid syndrom),如发育迟缓,个体矮小,难以繁殖后代等。在人类中,最为典型的例子为导致新生儿智力缺陷的唐氏综合症,由额外的一个21号染色体拷贝(部分拷贝)引起。此外,大多数癌细胞类型表型为严重的非整倍体。在大多情况下,非整倍体对于动物及人类是致命的,而植物对于非整倍体则往往表现出较强的耐受力,特别是在异源多倍体植物中。植物非整倍体对于植物的遗传、育种研究有重要意义,在基因及分子标记的物理位置确定,基因转移,连锁群与染色体的对应关系的确立上具有无可比拟的优势。该文综述了近些年来有关植物非整倍体研究的结果,介绍了非整倍体的几种重要成因和有关非整倍体鉴定手段的变迁,阐述了植物非整倍体对个体表型、基因表达以及表观遗传方面的影响,重点讨论了非整倍体在植物进化、基因组序列测定以及遗传改良方面的潜在作用。同时,探讨了植物非整倍体研究的新思路,以及利用非整倍体促进相关植物遗传改良、育种研究的新方法。

Abstract:

The aneuploidy for one species refers to the occurrence of one or more extra or subtractive chromosomes or chromosomal segments in the normal chromosome number in the somatic cells. Because of gene-dosage imbalance, compared to normal organisms, aneuploidy usually gives rise to severe defective phenotypes, such as delayed development and growth, stunted individual architecture, barrier of reproduction due to severe reducedfertility and so on. In human, the most serious aneuploidy syndrome is Down's syndrome with irreversible cognitive impairment, muscle hypotonia, as well as dysmorphic features in newborn, caused by one extra copy of the whole or partialchromosome 21. And the majority of solid tumor cells show different complex level aneuploidy. It is long recognized that plants have better tolerance to the impact of aneuploidy than animals, particularly in allopolyploid plants. As rare but vital germplasm resources, aneuploidy in crops is essential and powerful for these genetic improvements and advanced breeding studies which are focusing on confirmation of the physical location of valuable genes and assistant markers, and transferring of desirable genes from relative species in cultivars. Aneuploidies are also taken as convenient materials to identify the relationship between chromosomes in cytology and corresponding linkage groups in genetic map. In this review, we provided a concise but comprehensive review of recent studies in aneuploidy plant, in which we introduced some important mechanisms responsible for the formation of aneuploidies, the transition of identification methods for some typical aneuploidies, detrimental effects on organisms and cells caused by unbalanced chromosome, and gene expression change and epigenetic alteration of aneuploidy compared to normal organisms. And we particularly discussed some potential values of aneuploidies for the research of genome evolution in plant, and introduced important function of aneuploidy in allopolyploid crops to improve their genome sequencing and genetic improvement. Meanwhile, we sought some novel ideas and methods in the aneuploidy reseach, and also discussed the possibility of some new insights intogenetic improvement and advanced breeding with the aid of aneuploidy in some crops.