Mobility and application for molecular breeding of transposon-like gene Revolver aimed genetic plant development

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Revolver is a new class of transposon-like gene (US-2005-0091710) discovered in the Triticeae genome. Revolver encompassing 3041 bp has 20 bp of terminal inverted repeated sequence on the both ends, which features a class II transposable element. Revolver is transcriptionally active and its cDNA clone (726 bp) contains a single ORF encoding 118 amino acid residues of protein, which shows similarity with transcriptional regulators with DNA binding ability. The entire structure of Revolver dose not share identity with both the class I and class II transposable elements ever found. Southern blot analysis on the Triticeae plants shows that Revolver is abundant in the genomes of some wheat relatives, Secale (RR), Dasypyrum (VV), as well as wheat ancestor species, Triticum monococcum (AA), T.turgidum (AABB) and T.tauschii (DD). However, Revolver is rare in the genome of bread wheat T.aestivum (AABBDD). These facts indicate that Revolver has been existed since the diploid progenitor of wheat, then it has been disappearing in bread wheat through the evolution. Quantity of Revolver in wild emmer wheat Triticum dicoccoides, which is the tetraploid progenitor of bread wheat, was examined in 17 populations (209 genotypes) representing a wide range of ecological conditions of soil, temperature and water availability in Israel. Noticeable quantitative differences in copy numbers of Revolver was observed among the populations. T.dicoccoides in the population of Yehudiyya, Ammaid, Tabigha and Mt.Gerizim, where humid and temperate, had the highest number of copies (20,000) per haploid genome and that in the population of Kokhav-Hashahar, J'aba, Amirim, Beito-Oren, Bat-Shelomo, where seasonal hot and dry wind occurs over 85 days per year, had the lowest number (50 to 100). This extensive quantitative diversity among the locations suggests mobilization of Revolver by ecological stresses.