Crasta O R, Francki M G, Bucholtz D B, Sharma H C, Zhang J, Wang R C, Ohm H W, Anderson J M
CuraGen Corporation, New Haven, CT 06511, USA.
Genome. 2000 Aug;43(4):698-706.
Stable introgression of agronomically important traits into crop plants through wide crossing often requires the generation and identification of translocation lines. However, the low efficiency of identifying lines containing translocations is a significant limitation in utilizing valuable alien chromatin-derived traits. Selection of putative wheatgrass-wheat translocation lines based on segregation ratios of progeny from gamma-irradiated seed using a standard phenotypic analysis resulted in a low 4% success rate of identifying barley yellow dwarf virus (BYDV) resistant and susceptible translocation lines. However, 58% of the susceptible progeny of this irradiated seed contained a Thinopyrum intermedium chromosome-specific repetitive sequence, which indicated that gamma-irradiation-induced translocations occurred at high rate. Restriction fragment length polymorphism (RFLP) analysis of susceptible lines containing alien chromatin, their resistant sister lines and other resistant lines showed that more than one third of the progeny of gamma-irradiated double monosomic seeds contained wheatgrass-wheat translocations. Genomic in situ hybridization (GISH) analysis of selected lines confirmed that these were wheatgrass-wheat translocation lines. This approach of initially identifying BYDV susceptible deletion lines using an alien chromosome-specific repetitive sequence followed by RFLP analysis of their resistant sister lines efficiently identified resistant translocation lines and localized the BYDV resistance to the distal end of the introgressed Th. intermedium chromosome.
通过远缘杂交将重要农艺性状稳定导入作物植株通常需要产生和鉴定易位系。然而，鉴定含易位的品系效率较低，这是利用有价值的外源染色质衍生性状的一个重大限制。使用标准表型分析，基于γ射线辐照种子后代的分离比例来选择假定的冰草 - 小麦易位系，鉴定大麦黄矮病毒（BYDV）抗性和感病易位系的成功率仅为4%，很低。然而，这种辐照种子的感病后代中有58%含有中间偃麦草染色体特异性重复序列，这表明γ射线辐照诱导的易位发生率很高。对含有外源染色质的感病品系、它们的抗性姊妹系以及其他抗性品系进行限制性片段长度多态性（RFLP）分析表明，γ射线辐照的双单体种子后代中有超过三分之一含有冰草 - 小麦易位。对选定品系进行基因组原位杂交（GISH）分析证实这些是冰草 - 小麦易位系。这种方法首先使用外源染色体特异性重复序列鉴定BYDV感病缺失系，然后对其抗性姊妹系进行RFLP分析，有效地鉴定出抗性易位系，并将BYDV抗性定位到导入的中间偃麦草染色体的远端。
