National Key Facility for Crop Gene Resources and Genetic Improvement (NKCRI), Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Sci Rep. 2019 Jul 4;9(1):9712. doi: 10.1038/s41598-019-46197-6.
Agropyron cristatum (L.) Gaertn. (P genome) is cultivated as pasture fodder and can provide many desirable genes for wheat improvement. With the development of genomics and fluorescence in situ hybridization (FISH) technology, probes for identifying plant chromosomes were also developed. However, there are few reports on A. cristatum chromosomes. Here, FISH with the repeated sequences pAcTRT1 and pAcpCR2 enabled the identification of all diploid A. cristatum chromosomes. An integrated idiogram of A. cristatum chromosomes was constructed based on the FISH patterns of five diploid A. cristatum individuals. Structural polymorphisms of homologous chromosomes were observed not only among different individuals but also within individuals. Moreover, seventeen wheat-A. cristatum introgression lines containing different P genome chromosomes were identified with pAcTRT1 and pAcpCR2 probes. The arrangement of chromosomes in diploid A. cristatum was determined by identifying correspondence between the P chromosomes in these genetically identified introgression lines and diploid A. cristatum chromosomes. The two probes were also effective for discriminating all chromosomes of tetraploid A. cristatum, and the differences between two tetraploid A. cristatum accessions were similar to the polymorphisms among individuals of diploid A. cristatum. Collectively, the results provide an effective means for chromosome identification and phylogenetic studies of P genome chromosomes.
节节麦（L.）Gaertn.（P 基因组）被培育为牧草，可以为小麦改良提供许多理想的基因。随着基因组学和荧光原位杂交（FISH）技术的发展，也开发出了用于鉴定植物染色体的探针。然而，关于节节麦染色体的报道很少。在这里，使用重复序列 pAcTRT1 和 pAcpCR2 的 FISH 能够鉴定所有二倍体节节麦染色体。基于五个二倍体节节麦个体的 FISH 模式，构建了节节麦染色体的综合图谱。不仅在不同个体之间，而且在个体内部也观察到了同源染色体的结构多态性。此外，用 pAcTRT1 和 pAcpCR2 探针鉴定了包含不同 P 基因组染色体的十七个小麦-节节麦导入系。通过鉴定这些遗传鉴定的导入系中的 P 染色体与二倍体节节麦染色体之间的对应关系，确定了二倍体节节麦染色体的排列。这两个探针也可有效区分四倍体节节麦的所有染色体，并且两个四倍体节节麦品系之间的差异与二倍体节节麦个体之间的多态性相似。总之，这些结果为 P 基因组染色体的染色体鉴定和系统发育研究提供了有效手段。
