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

Revolver是在小麦族基因组中发现的一类新的转座子样基因（US-2005-0091710）。Revolver全长3041 bp，两端有20 bp的末端反向重复序列，具有II类转座因子的特征。Revolver具有转录活性，其cDNA克隆（726 bp）含有一个编码118个氨基酸残基的开放阅读框，与具有DNA结合能力的转录调控因子相似。对小麦族植物的Southern杂交分析表明，Revolver基因在小麦近缘种黑麦（Secale，RR）、簇毛麦（Dasypyrum，VV）以及小麦祖先种一粒小麦（Triticum monococcum，AA）、圆穗小麦（T.turgidum，AABB）和节节麦（T.tauschii，DD）的基因组中含量丰富。然而，Revolver在普通小麦（AABBDD）的基因组中是罕见的。这些事实表明，自小麦的二倍体祖先以来，左轮手枪就已经存在，然后在面包小麦中通过进化逐渐消失。在代表以色列广泛的土壤、温度和水资源生态条件的17个群体（209个基因型）中，研究了野生二粒小麦Triticum dicoccoides（面包小麦的四倍体祖先）中Revolver的数量。在种群中观察到Revolver拷贝数的显著数量差异。T.dicoccoides在Yehudiyya，Ammaid，Tabigha和Mt.Gerizim的种群中，在潮湿和温带，每个单倍体基因组的拷贝数最高（20，000），而在Kokhav-Hashahar，J 'aba，Amirim，Beito-Oren，Bat-Shelomo的种群中，季节性炎热和干燥风每年发生超过85天，数量最低（50 - 100）。这些地点之间广泛的数量多样性表明生态压力会动员左轮手枪。

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.