抗条锈病小偃麦双体异附加系山农87074-519的鉴定

综合利用抗性接种鉴定、细胞学分析、SSR分子标记和基因组原位杂交(GISH)技术相结合的方法,对从长穗偃麦草与小麦复合杂交后代中选育的抗条锈病种质系山农87074-519进行了鉴定。结果表明,山农87074-519的根尖细胞染色体数目2n=44,花粉母细胞减数分裂中期I(PMCMI)绝大多数细胞内可观察到22个二价体,平均染色体构型2n=44=21.82Ⅱ 0.36Ⅰ,它与普通小麦中国春杂种F1的多数花粉母细胞内染色体构型为2n=21Ⅱ 1Ⅰ,因此它是1个附加了1对长穗偃麦草染色体的双体异附加系;以假鹅冠草St基因组总DNA作探针进行原位杂交发现山农87074-519的44条染色体中有2条出现黄绿色杂交信号,且杂交信号遍布整条染色体,证明其附加的长穗偃麦草染色体为St基组;利用SSR分子标记技术,在170对SSR引物中筛选出特异引物BARC165,它能稳定地在山农87074-519中扩增出长穗偃麦草特异标记BARC165268;将长穗偃麦草中BARC165的特异扩增片段克隆测序后制备成探针进行原位杂交,可在山农87074-519的间期染色体和有丝分裂中期染色体检测到杂交信号。山农87074-519综合农艺性状较好,对条锈病免疫,其抗性基因为显性,且位于附加的长穗偃麦草St基组染色体上,暂将其表示为YrSt。该种质系在小麦的遗传改良中具有重要利用价值。

IDENTIFICATION OF TRITIELYTRIGIA ALIEN DISOMIC ADDITION LINE SHANNONG 87074-519 WITH YELLOW RUST RESISTANCE

In this paper, Shannong 87074-519, a derivative of wheat-decaploid Elytrigia elongata, was identified by inoculation assessment, cytological analysis, simple sequence repeat (SSR), molecular marker technique,and genomic in situ hybridization (GISH). The results are as follows: the chromosome number of Shannong87074-519 in root tip cells was 2n=44, 22 bivalents were observed in most PMC at MI, and the average chromosome configuration was 2n=44=21.82 II+0.36 I , and the chromosome configuration (2n=43=21 II +1 I) was observed in most PMC of F1 between Shannong87074-519 and C.S. at MI. Therefore, it was an alien disomic addition line with one pair chromosome of Elytrigia elongata. Then the St total genomic DNA was labeled as probe in GISH, the green-yellow hybridization signal was observed in two intact chromosomes, indicating that Shannong87074-519 was added by one pair chromosome of St genome. The SSR-PCR technique was employed in the primer filtration, and the molecular marker BARC165 was singled out from 170 primers, which could amplify the specific molecular marker BARC165(268) of Elytrigia elongata in Shannong87074-519. Subsequently, the specific segment in Elytrigia elongata was cloned and labeled as probe in GISH of root tip cells of Shannong87074-519, the light yellow hybridization signal was observed in both chromatin at interphase and chromosome at mitotic metaphase, thus the BARC165(268) could be applied as a specific molecular marker to detect alien chromatin of Elytrigia elongata in Shannong87074-519. Because of the good agronomic characteristics, high immunity to yellow rust, and dominant new yellow rust resistant gene located at the added chromosome St, assigned as YrSt temporarily, Shannong87074-519 has very important value in wheat breeding and genetics improvement.