Submitted to: International Triticeae Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/31/2005
Publication Date: 6/6/2005
Citation: Kishii, M., Wang, R., Tsujimoto, H. 2005. Gish analysis revealed new aspect of genomic constitution of thinopyrum intermedium--------------------------------------. International Triticeae Symposium Proceedings. Interpretive Summary:
Technical Abstract: Thinopyrum intermedium (Host) Barkworth & D. R. Dewey (2n=6x=42) is one of important alien species that had been utilized for wheat breeding programs. Even though it has been thought to compose of St (of genus Pseudoroegneria (Nevski) A. Love) and E/J genomes (of Thinopyrum elongatum (Host) D. R. Dewey/ Thinopyrum bessarabicum (Savul. & Rayss) A. Love), its exact genomic constitution has not been unsettled and has showed ambiguous features. To clarify this point, we conducted genomic in situ hybridization (GISH) analysis using many diploid species. The results revealed that Th. intermedium contains three kinds of genomes: St, E/J, and the third genome distinct from the previous two genomes. The third genome could be detected, in descending intensities, by probing V genome (of Dasypyrum (Coss. & Durieu) T. Durand), J and R (of Secale) genomes. Under GISH with V genome probe, the chromosomes of the third genome showed strong signals along the length but lacking signals around centromeric regions in several chromosomes and telomeric regions of all chromosomes. Medium signals of St genome, however, were detected in such regions where the signals of V genome were missing. The chromosomes of E/J genome also showed the signals of St genome in all telomeric regions. Therefore, the genomic formula of Th. intermedium can be tentatively re-designated as StStJsJs(V-J-R)s(V-J-R)s (where superscripted s stands for St genome signals in E/J and V-J-R genomes, and V-J-R stands for a progenitor or derivative genome involved in the evoluation of the three genomes). In the future, the cytogenetic analysis of meiotic pairing in hybrids would be necessary to lead to a final conclusion. Considering that there are several subspecies in Th. intermedium, it may be also necessary to evalute these subspecies by GISH to determine their genomic compositions. We also demonstrated that the probe of V genome would be useful to characterize wheat-Th. intermedium amphiploids and Th. intermedium chromosome addition lines of wheat.