普通小麦大赖草易位系T3AS·3AL-7Lr#1S的分子细胞遗传学鉴定

Molecular and cytogenetic identification of Triticum aestivum-Leymus racemosus translocation line T3AS·3AL-7Lr#1S

大赖草对赤霉病具有较好的抗性,将大赖草赤霉病抗性基因转入普通小麦,对拓宽小麦赤霉病抗性基础有重要意义。本研究在获得抗赤霉病普通小麦-大赖草异附加系基础上,采用1 200 R ^(60)Co-γ射线处理小麦-大赖草二体附加系DA7Lr花粉,授予已去雄的普通小麦中国春,对其后代(M_1)种子根尖细胞有丝分裂中期染色体进行GISH分析,获得了1株具有1条普通小麦-大赖草易位染色体的植株,让其自交,对自交后代中具有2条易位染色体植株的花粉母细胞减数分裂中期Ⅰ进行观察,发现2条易位染色体形成了稳定的环状二价体,表明该植株为纯合体。利用顺序GISH-双色FISH分析,结合C-分带、小麦D基因组专化探针Oligo-pAs1-2和B基因组专化探针Oligo-pSc119.2-2,进一步鉴定出该普通小麦-大赖草易位系为T3AS·3AL-7Lr#1S,且筛选出了可追踪该易位系的3个EST-STS分子标记BE591127、BQ168298和BE591737。该易位系的育成为小麦赤霉病遗传改良提供了新种质。

Leymus racemosus is highly resistant to wheat scab(Fusarum head blight, FHB). The transfer of scab resistant gene from L. racemosus to Triticum aestivum is of great significance for broadening the base of wheat resistance. In the present study, the pollen of T. aestivum-L. racemosus disomic addition line DA7 Lr with scab resistance was irradiated by60Co-γ-rays 1 200 R(100 R·min^-1) prior to pollinating to emasculated T. aestivum cv. Chinese Spring. One plant with a translocated chromosome was detected in the M1 by GISH. The plant with one translocation chromosome was self-pollinated, and at meiotic metaphase Ⅰ its progenies with two translocation chromosomes were analyzed for chromosome pairing behavior in their pollen mother cells(PMCs). One ring bivalent was observed, indicating that the plant with two translocation chromosomes was one translocation homozygote. C-banding and sequential GISH/FISH analysis, using Oligo-pAs1-2 and Oligo-pSc119.2-2 as probe, translocation line T3 AS·3 AL-7 Lr#1 S was confirmed. Three molecular markers of EST-STS such as BE591127, BQ168298 and BE591737 were screened, and these markers can be used to track the translocation line. The translocation line had good resistance to wheat scab and feasibility to be used as a new germplasm in wheat breeding resistant to scab disease.