Janeja H S, Banga S S, Lakshmikumaran M
Department of Plant Breeding, Punjab Agricultural University, Ludhiana-141004, India.
Theor Appl Genet. 2003 Jun;107(1):148-54. doi: 10.1007/s00122-003-1225-0. Epub 2003 Mar 27.
The tournefortii cytoplasmic male-sterility system is being used as a method of pollination control to develop hybrids in Brassica napus. Genetic analyses have indicated that two dominant genes, one major ( Rft1) and another minor ( Rft2), were required to achieve complete fertility restoration. Though the major gene ( Rft1) can cause complete fertility restoration on its own, its expression was significantly enhanced in the presence of the minor gene ( Rft2). In the absence of Rft1, Rft2 caused only partial fertility restoration. We used a pair of near-isogenic lines (NILs), differing for the presence/absence of Rf genes, to identify AFLP markers linked to fertility restorer genes. A total of 64 EcoRI/ MseI primer combinations were surveyed which produced 3,225 bands, of which 19 (0.006%) were polymorphic between parental NILs. Primer combinations which led to the identification of polymorphic bands present in fertile parental NILs were used for assaying a mapping population of 70 F(2) plants for determining the segregation pattern of markers. Initial screening resulted in the identification of five AFLP markers. The recombination analyses of these AFLP markers revealed that at least two (EACC/MCTT(105), EAAG/MCTC(80)) were present in the same linkage group along with the Rf loci. Marker EACC/MCTT(105) was separated from the major gene ( Rft1) by a distance of 18.1 cM, while it was 33.2 cM away from the minor fertility restorer gene ( Rft2). Another marker EAAG/MCTC(80) was also located adjacent to Rft1 at a distance of 18.1 cM, but on other side. Identification of flanking markers (EACC/MCTT(105), EAAG/MCTC(80)) for the major fertility restorer gene ( Rft1) provides a crucial component for marker-assisted selection and map-based cloning of the restorer genes, and can hence be used to construct elite restorer genotypes.
图尔纳福特细胞质雄性不育系统正被用作一种授粉控制方法，以培育甘蓝型油菜杂交种。遗传分析表明，需要两个显性基因，一个主效基因（Rft1）和另一个微效基因（Rft2）才能实现完全育性恢复。虽然主效基因（Rft1）自身就能导致完全育性恢复，但其在微效基因（Rft2）存在时表达显著增强。在没有Rft1的情况下，Rft2仅能导致部分育性恢复。我们使用了一对近等基因系（NILs），它们在是否存在Rf基因方面存在差异，以鉴定与育性恢复基因连锁的AFLP标记。共检测了64种EcoRI/MseI引物组合，产生了3225条带，其中19条（0.006%）在亲本NILs之间具有多态性。导致鉴定出可育亲本NILs中存在的多态性条带的引物组合，被用于检测由70株F2植株组成的作图群体，以确定标记的分离模式。初步筛选鉴定出了5个AFLP标记。对这些AFLP标记的重组分析表明，至少有两个（EACC/MCTT(105)、EAAG/MCTC(80)）与Rf位点位于同一连锁群中。标记EACC/MCTT(105)与主效基因（Rft1）的距离为18.1厘摩，而与微效育性恢复基因（Rft2）的距离为33.2厘摩。另一个标记EAAG/MCTC(80)也位于Rft1附近，距离为18.1厘摩，但在另一侧。鉴定出主效育性恢复基因（Rft1）的侧翼标记（EACC/MCTT(105)、EAAG/MCTC(80)）为标记辅助选择和基于图谱的恢复基因克隆提供了关键组成部分，因此可用于构建优良的恢复基因型。
