Fu Da-Xiong, Ruan Ren-Wu, Wen Hai-Xia, Chen Yun-Ping, Zong Xue-Feng, Yin Jia-Ming, Dai Xiu-Mei, Zhang Jian-Kui
College of Agronomy and Life Science, Southwest Agricultural University, Chongqing 400716, China.
Yi Chuan Xue Bao. 2002 Dec;29(12):1085-94.
The "Taigu" genic sterility gene Ms2 located on the short arm of the 4D chromosome of common wheat (AABBDD) originally incorporated into hexoploid triticale (AABBRR) and durum wheat (AABB) through intergenomic translocation in distant hybridization was introduced back into the genomes of common wheat. The dominant male sterility was expressed normally in the new "Taigu" genic sterile wheat carrying the intergenomically translocated Ms2, and the female fertility mechanism in its male sterile plants was normal as well. Observation of the chromosome configuration at meiosis of pollen mother cells (PMC) of the young ears of the sterile plants showed that they were euploid plants (2n = 42). No configurations different from those of the "Taigu" genic sterility gene located at the original locus were noticed of the Ms2 intergenomically translocated back into the common wheat. In systematic test crosses with marker genes the intergenomically translocated gene Ms2 was found to be linked with the dominant dwarf marker in common wheat Rht3 and, consequently, remapped and located on the short arm of the 4B chromosome of common wheat with a distance of 9.7 cM from Rht3. The new locus was designated as Ms2 (4BS). Discussions are given of the fate of Ms2 during translocation in the hexoploid triticale, the exchange of the names for 4A and 4B chromosomes in common wheat and the possible exploitation of the new locus Ms2 (4BS), and the following speculations are made: (a) In genic genes of allopolyploid organisms the donor chromosomes tend to be intergenomically translocated to their physiologically and evolutionarily close chromosomes with the same order number and the same arm; (b) it is confirmed that the 7th International Conference of Wheat Genetics was right to exchange the names between chromosomes 4A and 4B of common wheat in 1988; and (c) as a new genetic marker and a breeding tool for all the chromosome B-carrying species in the tribe of Triticeae, Ms2(4BS) may have wide application in building and expanding the gene pool of germplasm resources of various species of wheat.
普通小麦（AABBDD）4D染色体短臂上的“太谷”核不育基因Ms2最初通过远缘杂交中的基因组间易位整合到六倍体小黑麦（AABBRR）和硬粒小麦（AABB）中，随后又被导入普通小麦基因组。携带基因组间易位Ms2的新型“太谷”核不育小麦中，显性雄性不育正常表达，其雄性不育植株的雌性育性机制也正常。对不育植株幼穗花粉母细胞（PMC）减数分裂时的染色体构型观察表明，它们是整倍体植株（2n = 42）。未发现基因组间易位回到普通小麦的Ms2与位于原始位点的“太谷”核不育基因的构型有差异。在与标记基因的系统测交中发现，基因组间易位的基因Ms2与普通小麦中的显性矮秆标记Rht3连锁，因此重新定位并定位于普通小麦4B染色体短臂上，与Rht3的距离为9.7 cM。新位点被命名为Ms2（4BS）。文中讨论了Ms2在六倍体小黑麦易位过程中的命运、普通小麦4A和4B染色体名称的交换以及新位点Ms2（4BS）的可能利用，并做出以下推测：（a）在异源多倍体生物的基因中，供体染色体倾向于基因组间易位到生理和进化上相近、序号相同且臂相同的染色体上；（b）证实了1988年第七届国际小麦遗传学会议对普通小麦4A和4B染色体名称进行交换是正确的；（c）作为一个新的遗传标记和用于小麦族中所有携带B染色体物种的育种工具，Ms2（4BS）可能在构建和扩大各种小麦种质资源基因库方面有广泛应用。
