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紫米因其种皮内花色素苷的沉积而着色.控制种皮着色的Pb基因位于水稻第4染色体,紫色种皮对白色种皮呈显性.本研究利用培矮64S(白米)×豫南黑籼糯(紫米)和培矮64S×川黑糯(紫米)两个F2分离群体对Pb基因进行了精细定位.首先用SSR标记将Pb基因初步定位在距微卫星位点RM3820下游0.79cM的位置.然后,通过在候选区域内发展高密度的InDel标记和CAPS标记,将Pb基因限定在两个InDel标记RID3与RID4之间25kb范围以内.在该区段内,TIGR水稻基因组(R.5)标有两个注释基因:一个为与玉米Lc基因同源的Ra,为控制花色素苷代谢的Myc类转录因子;另一个为与拟南芥TT8同源的bhlh16,也与植物色素代谢有关.根据两者的性质和前人相关研究结果,推测Pb与Ra实为同一个基因.序列分析结果表明,与白米品种培矮64S,9311(籼)和日本晴(粳)相比,豫南黑籼糯和川黑糯中Ra基因第7外显子存在一个GT缺失.根据GT缺失发展了一个CAPS标记CAPSRa,并对两个F2分离群体和100余份水稻品种进行分析.结果发现,所有F2白米单株以及所有白米(n=63)和红米(n=23)品种的CAPSRa基因型与培矮64S相同,而所有紫米品种(n=20)与豫南黑籼糯和川黑糯相同.据此推测,水稻紫色种皮性状可能由Ra基因第7外显子内的GT缺失引起.
Purple rice was colored by the deposition of anthocyanin in its seed coat.The Pb gene controlling the seed coat color was located on the fourth chromosome of rice and the purple seed coat was dominant on the white seed coat.This study used Pei’ai 64S The Pb gene was finely mapped by two F2 segregating populations of South Black Indica Glutinous Rice (Purple Rice) and Pei’ai 64S × Chuanhei Nuo (Purple Rice) .Primer gene was initially located at the downstream of the microsatellite locus RM3820 by SSR marker 0.79cM.The Pb gene was then defined within 25kb of the two InDel markers RID3 and RID4 by developing high density InDel and CAPS markers within the candidate region Within this segment the TIGR rice genome R.5) is annotated with two annotation genes: one is Ra homologous to the Lc gene of maize, the Myc transcription factor that controls the metabolism of anthocyanins, the other is bhlh16 homologous to Arabidopsis TT8, According to the nature of the two and the related research results, it is speculated that Pb and Ra are the same gene.Sequence analysis showed that compared with the white cultivars Pei’ai 64S, 9311 (indica) and Nipponbare (japonica) There is a GT deletion in exon 7 of Ra gene in black indica glutinous rice and chuannanguo glutinous rice in southern Henan.According to GT deletion A CAPS marker CAPSRa was presented and two F2 populations and more than 100 rice cultivars were analyzed.The results showed that CAPSRa of all F2 white rice and all rice varieties (n = 63) and red rice (n = 23) The genotype was the same as that of Pei’ai 64S, but all the purple varieties (n = 20) were the same as Heinaxiannuo and Chuannanguo, suggesting that the purple seed coat characters of rice might be caused by GT missing caused.