Chromosome assignment of four photosynthesis-related genes and their variability in wheat species
1994
Ogihara, Y. | Shimizu, H. | Hasegawa, K. | Tsujimoto, H. | Sasakuma, T. (Yokohama City Univ. (Japan). Kihara Inst. for Biological Research)
Copy numbers of four photosynthesis-related genes, PhyA, Ppc, RbcS and Lhcb1*1, in wheat genomes were estimated by slot-blot analysis, and these genes were assigned to the chromosome arms of common wheat by Southern hybridization of DNA from an aneuploid series of the cultivar Chinese Spring. The copy number of PhyA was estimated to be one locus per haploid genome, and this gene was assigned to chromosomes 4AL, 4BS and 4DS. The Ppc gene showed a low copy number of small multigenes, and was located on the short arm of homoeologous group 3 chromosomes and the long arm of chromosomes of homoeologous group 7. RbcS consisted of a multigene family, with approximately 100 copies in the common wheat genome, and was located on the short arm of group 2 chromosomes and the long arm of group 5 chromosomes. Lhcb1*1 also consisted of a multigene family with about 50 copies in common wheat. Only a limited number of restriction fragments (approximately 15%) were used to determine the locations of members of this family on the long arm of group 1 chromosomes owing to the multiplicity of DNA bands. The variability of hybridized bands with the 4 genes was less in polyploids, but was more in the case of multigene families. RFLP analysis of polyploid wheats and their presumed ancestors was carried out with probes of the oat PhyA gene, the maize Ppc gene, the wheat RbcS gene and the wheat Lhcb1*1 gene. The RFLP patterns of common wheat most closely resembled those of Triticum dicoccum (Emmer wheat), Triticum urartu (A genome), Aegilops speltoides (S genome) and Aegilops squarrosa (D genome). Diversification of genes in the wheat complex appear to have occurred mainly at the diploid level. Based on RFLP patterns, B and S genomes were clustered into two major groups.
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