粳稻为背景的普通野生稻单片段代换系群体的初步构建

Preliminary development on single segment substitution lines population of common wild rice (Oryza rufipogon) based on Japonica background

以粳稻日本晴(O.sativa L.subsp.Japonica cv.Nipponbare)为受体和轮回亲本,以广西普通野生稻核心种质DP15为供体,通过连续回交和SSR标记辅助选择的方法构建普通野生稻单片段代换系群体(Single segment substitution lines,SSSLs)。用覆盖水稻全基因组的563对SSR引物检测供体(DP15)和受体(日本晴)的多态性,从中挑选212对分布在水稻12条染色体上的多态性引物跟踪供体基因型。结果表明,在BC3F1代获得79个代换片段,这些片段基本上能相互重叠并覆盖水稻12条染色体,其中第1、第2条染色体含有的代换片段数最多,均为9个,第9、第10和第12条染色体含有的代换片段数最少且均为5个。79个代换片段长度为12.65～113.55 cM,平均长度为54.3 cM,总覆盖长度为4285.28cM,是水稻整个染色体组长度的2倍多,覆盖野生稻全基因组达98.89%。随机选取其中的6个代换株系用96个多态性引物检测其遗传背景,发现供体DNA残留率为7.3%～15.6%。今后将继续通过回交和标记辅助选择,以获得一整套覆盖普通野生稻全基因组的SSSL库,这将有助于研究稻种的起源、演变和分化以及普通野生稻的功能基因组。

In the present study, series of single DNA segment substitution lines （SSSL） of common wild rice （Oryza rufipogon） based on japonica background were developed by employing O. sativa L. subsp. Japonica cv. Nipponbare as recipient and recurrent parent, and core material DP15 of common wild rice in Guangxi as donor through continuous backcross and SSR marker-assisted selection. A total of 563 SSR markers which covered the whole genome of rice were used to analyze the polymorphism between donor （DP15） and recipient （Nipponbare）, and 212 polymorphic markers distributed on the 12 chromosomes were evenly selected to trace the genotypes of donor. The results demonstrated that 79 substituted DNA segments were obtained in BC3F1, and these segments were basically lapped over each other and covered all the 12 chromosomes. Out of 12 chromosomes, chromosome 1 and 2 had the most substituted segments （9）, while chromosome 9, 10 and 12 the least （5）. The estimated lengths of 79 substituted segments ranged from 12.65 cM to 113.55 cM with an average of 54.3 cM. Total length of substituted segments in SSSL population was 4285.28 cM, which was two times more of the whole rice genome. The substituted segments provided a coverage of 98.89% of common wild rice genome. Moreover, six substitution lines were randomly selected to examine their genetic backgrounds with 96 polymorphic markers, and it was found that the residual rates of donor＇s DNA ranged from 7.3% to 15.6%. Further researches are needed to achieve SSSLs covering the whole genome of common wild rice by continuous backcross and marker-assisted selection. This will help in the researches of origin, evolution, and differentiation of rice and functional genomic researches of common wild rice.