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United States Department of Agriculture

Agricultural Research Service

Title: Gish Analysis Revealed New Aspect of Genomic Constitution of Thinopyrum Intermedium

Authors
item Kishii, M - CIMMYT
item Wang, Richard
item Tsuijimoto, H - TOTTORI UNIVERSITY

Submitted to: Czech Journal of Genetics and Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 28, 2005
Publication Date: December 20, 2005
Citation: Kishii, M., Wang, R., Tsuijimoto, H. 2005. Gish analysis revealed new aspect of genomic constitution of thinopyrum intermedium. Czech Journal of Genetics and Plant Breeding 41:92-95

Interpretive Summary: Intermediate wheatgrass (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 settled and has showed ambiguous features. To clarify this point, we conducted genomic in situ hybridization (GISH) analyses 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 (or 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 evolution 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 evaluate 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.

Technical Abstract: We conducted genomic in situ hybridization (GISH)analyses to clarify genomic constitutions of Thinopyrum intermedium (Host) Barkworth & D. R. The results revealed that Th. intermedium contains three kinds of genomes: St, E/J, and the third genome distinct from the previous two genomes which may be close to V genome. However, PCR analysis denied the presence of the present-day V genome in Th. intermedium but showed some similarity in R genome. Thus, the genomic formula of Th. intermedium can be tentatively re-designated as StStJsJs(V-J-R)s(V-J-R)s. 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.

Last Modified: 7/30/2014
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