水稻广亲和基因S5-n的功能标记开发及其应用

Development and Application of a Functional Marker for Wide Compatibility Gene S5-n of Rice

广亲和基因S5-n是能够恢复籼、粳杂种育性的基因,利用常规育种方法回交转育广亲和基因需要通过配组杂种F1,根据F1的育性判断和选择S5-n,选育周期长,方法繁琐。因此,在广亲和遗传改良和聚合育种中需要寻找一种快速、简便的广亲和基因检测方法。本研究根据水稻广亲和基因和籼粳S-5等位基因序列存在136bp缺失的特征,设计了InDel标记S5136。前人研究已经明确02428、Dualr、CPSLO17具有S5-n,分子标记S5136 PCR扩增这3个材料的带型为缺失带型,而不携带广亲和基因S5-n的材料的带型为非缺失带型。利用该标记对3037与02428的F2群体分析表明,该标记能准确区分S5-n、S5-i纯合及杂合基因型,标记基因型符合1∶2∶1比例,没有发生偏分离现象。利用该标记从554份水稻品种资源(O.sativa L.)和27份普通野生稻(O.rufipogen Griff.)以及24份江淮流域杂草稻资源中筛选出具有缺失带型的资源材料13份,并对其PCR产物测序证实为S5-n,对Kasalath的广亲和性进行了初步验证;从20份02428的高世代育种材料中,筛选到携带广亲和基因S5-n的恢复系2份。该标记可以用于S5-n基因资源筛选、分子标记辅助选择育种和培矮64S为母本的杂交种种子纯度鉴定。

Wide compatibility varieties （WCVs） with S5-n are able to produce highly fertile hybrids when crossed to both indica and japonica varieties. The conventional breeding strategy of pyramiding S5-n is to test the fertility of F1 hybrid. However, this method is labour-consuming, time-consuming and difficult in operation. The technically simplified approach of marker-assisted selection（MAS） has directly and practically used in rice breeding. Therefore, it is urgent to find a convenient and efficient way in WCV breeding with MAS. The wide compatibility gene （S5-n） has 136 bp deletion compared with the indica and japonica S-5 alleles. In order to improve the precision of marker-assisted selection for S5-n, we developed the functional marker S5136 based on the deletion in the DNA sequence of S5-n. The differentiation for S5-n, S5-i, and S5-j in 24 accessions of weedy rice from the district of Yangtze and Huaihe Rivers, 27 accessions of common wild rice （O. rufipogon Grill.） from China, 554 cultivars and genetic resources （O. sativa L.） and 20 breeding lines was investigated by $5136. The results indicated that this marker was low-cost, robust technique that can be utilized to identify the S5-n in WCVs like 02428, Dular and CPSLO17. The S5136 could distinguish the homozygous S5-n/SS-n, homozygous S5-i/S5-i, and heterozygous S5-n/S5-i individuals in F2 population derived from 3037 and 02428. From the tested materials, 13 germplasms with S5-n were identified and conformed by sequencing the S5136 PCR products, and 2 restore lines with SS-n developed from the offspring of 02428 were identified. Also, the compatibility of Kasalath was tested with some indiea-japonica hybrids. Therefore, S5136 is a powerful molecular marker in S5-n germplasm screening, perfect marker- assisted selection breeding and seed purity testing for the two line hybrids with Pei＇ai 64S as maternal parent.