水稻杂种偏分离位点SegD8的精细定位

Fine-mapping of SegD8 Loci for Rice Hybrid Segregation Distortion

【目的】通过研究水稻渐渗系群体构建时产生的偏分离现象,可以发现更多与偏分离相关的基因,有助于解析偏分离在水稻中的主要作用及其产生机制。【方法】应用籼粳组合华占/Koliya构建的一套渐渗系群体,以其后代基因型的分离比作为表型对偏分离位点进行定位。【结果】在第8染色体上发现一个染色体区段在其后代中的基因型分离比偏离孟德尔分离定律。进一步分析表明该偏分离现象受第8染色体上两个位点控制,分别命名为SegD8A和SegD8B,其中SegD8A为偏分离位点,但其偏分离属性受SegD8B调控。当SegD8A和SegD8B位点都为杂合型时,子代中SegD8A^(HH)和SegD8A^(KK)的比例接近1∶4;当SegD8B为纯合华占基因型时,子代中SegD8A^(HH)和SegD8A^(KK)的比例接近1∶1;当SegD8B为纯合Koliya基因型时,子代中SegD8A^(HH)几乎不出现。我们将SegD8A基因定位在一个大小为46.5 kb的区间内,SegD8B基因定位在一个大小为1160.2 kb的区间内。【结论】本研究为进一步克隆这两个基因,并阐明该偏分离现象奠定了基础。

【Objective】This study aims to fine-map and clone genes related to segregation distortion(SD)by using a rice introgressive line population,and thus to explore the molecular mechanism underlying the segregation distortion in rice.【Method】A set of introgressive line population was constructed by using an indica/japonica combination Huazhan/Koliya.The gene loci were mapped with different genotype separation ratios of offspring as phenotypes.【Result】We identified a segment on chromosome 8 that displayed obvious deviated segregation ratio from Mendelian's separation law.Further analysis revealed that the SD was controlled by two loci on chromosome 8,which were termed as SegD8A and SegD8B,respectively.SegD8A was a segregation locus,but its segregation was regulated by SegD8B.When both SegD8A and SegD8B were heterozygous,the ratio of SegD8A^(HH) and SegD8A^(KK) in progeny was close to 1:4.When SegD8B was homozygous Huazhan genotype,the ratio of SegD8A^(HH) and SegD8A^(KK) in progenies was close to 1:1.When SegD8B was homozygous Koliya genotype,SegD8A^(HH) almost did not appear in its progeny.The SegD8A gene was mapped to a 46.5 kb region and the SegD8B gene was mapped to an 1160.2 kb region using the separation ratio of the progeny.【Conclusion】The results lay a foundation for further cloning of these two genes and elucidating the partial separation phenomenon.