Motonori Tomita

Revolver is a New Class of Transposon-like Gene Composing the Triticeae Genome

Revolver discovered in the Triticeae plant is a novel class of transposon-like gene and a major component of the large cereal genome. An 89 bp segment of Revolver that is enriched in the genome of rye was isolated by deleting the DNA sequences common to rye and wheat. The entire structure of Revolver was determined by using rye genomic clones, which were screened by the 89 bp probe. Revolver consists of 2929—3041 bp with an inverted repeated sequence on each end and is dispersed through all seven chromosomes of the rye genome. Revolver is transcriptionally active, and the isolated full-length cDNA (726 bp) reveals that Revolver harbors a single gene consisting of three exons (342, 88, and 296 bp) and two introns (750 and 1237 bp), and encodes 139 amino acid residues of protein, which shows similarity to some transcriptional regulators. Revolver variants ranging from 2665 to 4269 bp, in which 5′ regions were destructed, indicate structural diversities around the first exon. Revolver does not share identity with any known class I or class II autonomous transposable elements of any living species. DNA blot analysis of Triticeae plants shows that Revolver has existed since the diploid progenitor of wheat, and has been amplified or lost in several species during the evolution of the Triticeae.

Limited but specific variations of seed storage proteins in Japanese common wheat (Triticum aestivum L.)

The electrophoretic banding patterns ofgliadin in common wheat lines derived fromJapan were determined byacid-polyacrylamide gel electrophoresis. For the 107 wheat lines used in our study,27 different patterns were identified, 13corresponding to the ο-gliadin, 8 tothe β, γ-gliadin and 6 to theα-gliadin. The gliadin patterns ofJapanese wheat cultivars and landracesgreatly differed from the patterns of wheatlines from other countries, and thevariation seen in wheat lines from Japanwas limited to 46 patterns. Sevencollection or breeding areas in Japanshowed different frequencies in theirgliadin patterns. Combining the gliadinpatterns with high molecular weightglutenin subunit compositions, 67combinations were observed. One gliadinpattern consisting of ο-gliadinpattern F, β, γ-gliadinpattern H and α-gliadin pattern Dwas frequently found in many Japanese wheatlines, though the other patterns werelimited to only one or two wheat lines.

Centromeric distribution of 350-family in Dasypyrum villosum and its application to identifying Dasypyrum chromatin in the wheat genome

Variants of the 350-family sequences were isolated from Dasypyrum villosum genomic DNA. Although the consensus sequence shared 86% homology to p380 and 84% homology to pHvNAU62 of D. villosum, a 63 bp long region including variable microsatellite repeat (TG)(7-9) was found to be absent in pHvNAU62 or much different from p380. This sequence also shared 67% homology to the 350-family of rye. The representative clone pDvTU383 was localized on the D. villosum chromosomes by using the sequential C-banding and fluorescence in situ hybridization (FISH). Combining with the probes of pTa71 and pTa794 containing 18S-5.8S-28S rDNA (NOR) and 5S rDNA multigene families, respectively, the pDvTU383 probe allowed identification of all seven pairs of D. villosum chromosomes. The pair of the 1V chromosomes fluoresced strong in situ hybridization signals of 18S-5.8S-28S rRNA genes in the NORs of 1VS, and the pair of the 5V chromosomes had weak signals of 5S rRNA genes at the end of 5VS. The pair of the 4V chromosomes showed sub-telomeric signals of pDvTU383 probe on the both arms, however, the signal of the short arm is weaker than that of the long arm. The pair of the 7V chromosomes showed no signals of pDvTU383 on the both sub-telomeric regions. The pair of the 6V chromosomes showed a characteristic interstitial signal of pDvTU383 on the short arm. The pairs of the 2V and 3V chromosomes were distinguished by the difference of interstitial signals of pDvTU383 on their long arms. Furthermore, hybridization signals of pDvTU383 were also visualized on centromeres of all chromosomes. Based on the above D. villosum chromosomal patterns made by FISH, one pair of the 4V chromosomes originated from D. villosum were found in a trigeneric hybrid line involving wheat, Dasypyrum and Thinopyrum. The sequence pDvTU383 provides an effective probe for further analysis of the D. villosum genome.