Garg Monika, Elamein Hala M M, Tanaka Hiroyuki, Tsujimoto Hisashi
Laboratory of Plant Genetics and Breeding Science, United Graduate School of Agricultural Sciences, Tottori University, Japan.
Genes Genet Syst. 2007 Oct;82(5):403-8. doi: 10.1266/ggs.82.403.
Alien chromosome addition lines are useful genetic material for studying the effect of an individual chromosome in the same genetic background. However, addition lines are sometimes unstable and tend to lose the alien chromosome in subsequent generations. In this study, we report preferential removal of chromosome 1D rather than the alien chromosome from homoeologous group-1 addition lines. The Agropyron intermedium chromosome 1Agi (1E) addition line, created in the background of 'Vilmorin 27', showed loss of a part of chromosome 1D, thereby losing its HMW glutenin locus. Even in the case of Aegilops longissima and Ae. peregrina, the genomes of which are closer to the B genome than D genome, chromosome 1D was lost from chromosome 1Sl and 1Sv addition lines in cv. 'Chinese Spring' rather than chromosome 1B during transfer from one generation to another. A similar observation was also observed in the case of a chromosome 1E disomic addition line of Ag. elongatum and alloplasmic common wheat line with Ag. intermedium ssp. trichophorum cytoplasm. The reason for this strange observation is thought to lie in the history of wheat evolution, the size of chromosome 1D compared to 1A and 1B, or differing pollen competition abilities.
异源染色体附加系是在相同遗传背景下研究单个染色体效应的有用遗传材料。然而，附加系有时不稳定，在后代中容易丢失异源染色体。在本研究中，我们报道了在同源群1附加系中优先去除1D染色体而非异源染色体的现象。在‘维尔莫林27’背景下创建的中间偃麦草染色体1Agi(1E)附加系，显示出1D染色体的一部分丢失，从而失去了其高分子量谷蛋白基因座。即使在长穗偃麦草和野生二粒小麦的情况下，它们的基因组与B基因组的亲缘关系比与D基因组更近，在从一代到另一代的转移过程中，在‘中国春’品种的1Sl和1Sv附加系中丢失的是1D染色体而非1B染色体。在长穗偃麦草的1E二体附加系和带有中间偃麦草亚种毛稃偃麦草细胞质的异质普通小麦系中也观察到了类似现象。这种奇怪现象的原因被认为在于小麦的进化历史、1D染色体与1A和1B染色体相比的大小，或者不同的花粉竞争能力。
