植物B染色体的分子结构组成及遗传机制研究进展

Progress on molecular composition and genetic mechanism of plant B chromosomes

B染色体(B chromosomes, Bs)是独立于常规染色体即A染色体(A chromosomes, As)的一类特殊染色体。长期以来,由于实验方法的限制和B染色体可有可无的性质,B染色体一直被认为是完全由异染色质组成且不携带任何功能基因。随着高通量测序技术的发展,很多物种的B染色体被分离,通过对其DNA组成进行全面分析,发现B染色体也携带蛋白质编码基因且对宿主的转录和蛋白表达有影响。本文以黑麦(Secale cereale L.)、玉米(Zea mays L.)和拟斯卑尔脱山羊草(Aegilops speltoides Tausch.)为例,主要介绍了B染色体对植物表型的影响、B染色体的分子结构及DNA重复序列组成、B染色体的功能基因研究,并讨论了植物B染色体领域的研究现状及潜在的应用前景,旨在为染色体工程和育种提供新思路。

In addition to the standard set of chromosomes(A chromosomes, As), so-called supernumerary B chromosomes(Bs) have been found causing a numerical chromosome variation. Bs have been considered to be genetically inert elements without any functional genes for a long period, because of the limited experimental methods and its dispensable property.More recently, sequencing of dissected Bs from several organisms has revealed the DNA composition, a vast number of protein-coding genes have been found with the effects on the transcripts and protein expression of the host. In this review,we summarize current understanding of B chromosomes carrying plants including rye(Secale cereale L.), maize(Zea mays L.) and Aegilops(Aegilops speltoides Tausch.), with the emphasis on Bs phenotypic effects, the inheritance mechanism of Bs, the molecular composition of Bs, the effects on host transcription regulation and protein expression upon the presence of Bs. Besides, we discuss the current study state and potential application of B chromosomes, aim to provide a new venue for chromosome engineering and breeding research.