MOLECULAR STUDIES ON NUCLEAR GENE(S) INTERACTING WITH RYE CYTOPLASM Construction of YAC library with telomere sequences

在具有黑麦细胞质的普通小麦品系中，发现至少有一条被称为“侏儒”的小染色体出现。在减数分裂时，侏儒染色体不与任何小麦染色体配对，没有这条染色体的小麦种子由于胚乳流产而无法存活，即使能发芽，也是高度不育的。这些结果表明，小染色体来源于黑麦染色体的某些片段，具有黑麦细胞质功能所必需的基因。为了分析该基因，在本研究中，我们尝试使用RDA（代表性差异分析）和RAPD（随机扩增多态性DNA）方法扩增小染色体特异性DNA序列。然而，没有检测到特定的DNA。此外，我们还构建了一个优先包含（谷类）-CS端粒序列的YAC文库。对拟南芥端粒序列的集落杂交证明，400个酵母转化子中约有80个克隆携带植物端粒。虽然在这个库中发现了多达600kb-YAC的克隆，但插入大小通常比预期的要小；< 20 kb。目前，以黑麦基因组DNA为探针，通过集落杂交，从黑麦的侏儒染色体中获得了一个100kb-YAC。

In a common wheat strain with rye cytoplasm, at least one diminutive chromosome, called "midget" is found to occur. The midget chromosome does not pair with any of the wheat chromosomes at meiosis, and the seeds of this strain without this chromosome are inviable because of their endosperm abortion, and even germinable, they are highly sterile. These results indicate that the midget chromosome was derived from certain segment(s) of rye chromosome(s), having the gene(s) essential for rye cytoplasmic function. To analyze the gene(s), in this study, we attempted to amplify the midget chromosome-specific DNA sequences by using the RDA (Representational Difference Analysis), and the RAPD (Random Amplified Polymorphic DNA) methods. However, no specific DNA was detected.Furthermore, we have constructed a YAC library that preferentially contains telomere sequences from (cereale)-CS.Colony hybridization with the telomere sequence of Arabidopsis thaliana as a prove exhibited that about 80 clones of 400 yeast transformants carried plant telomeres. Although u up to 600kb-YAC clones were found in this library, the insert size was generally samller than expected ; <20kb. So far, a 100kb-YAC has been suggested to be derived from the midget chromosome by colony hybridization with rye genomic DNA as a probe.