小麦-茸毛偃麦草异附加系Y176-3的分子细胞遗传学鉴定

Molecular Cytogenetics Identification of a Wheat-Thinopyrum intermedium ssp.trichophorum Addtion Line Y176-3

为了解茸毛偃麦草(Thinopyrum intermediumssp.trichophorum)与小麦经过杂交、回交所选育的小偃麦新种质Y176-3的遗传特性,对该系进行了抗条锈性鉴定与分子细胞学分析。结果表明,Y176-3对当前的条锈病流行小种和新小种免疫。其根尖细胞染色体数目为2n=44,有2对随体,花粉母细胞减数分裂中期I(PMC MI)染色体构型为2n=22Ⅱ。利用C-带分析,观察到Y176-3中可能附加了一对来自茸毛偃麦草的端部有强带的短染色体。以拟鹅观草(Pseudoroegneria spicata,2n=14)DNA作探针、中国春基因组DNA为封阻进行的原位杂交结果表明,Y176-3含有2条较短的茸毛偃麦草染色体,该染色体属于St组,推测新种质Y176-3中导入的来自茸毛偃麦草的St染色体可能携带新的抗条锈病基因。

In this study, wheat line Y176-3 with high resistance to strip rust, which derived from Sichuan wheat×Thinopyrum interrnediurn ssp. trichophorum was characterized by cytological and GISH analysis. The results showed that chromosome number of Y176-3 in root tip cell was 44, including four satellite chromosomes. Twenty-two bivalents were frequently observed in meiotic chromosome configuration of PMC MI. Giemsa-C banding showed the two smaller chromosomes of Th. trichophorurn with tolemeric bands maybe added in Y176-3. In order to reveal the genomic distribution of the added chromosomes of Y176-3, the Genomic in situ hybridization （GISH） was carried out by using the St genome as a probe, and the common wheat genomic DNA as a blocker. The results indicated that the introduced Th. trichophorurn chromosomes belong to St genome. It is concluded that the introduced Thinopyrurn chromosomes in Y176-3 might contain new genes responsible for its stripe rust resistance.