Aligning Physical and Functional Maps of a Genomic Region Spanning the Apomixis Locus by Exploiting Model Cereal Genomics

通过利用谷物基因组学模型来对齐跨越无融合生殖基因座的基因组区域的物理和功能图谱

• 批准号: 0115911
• 负责人: Peggy Ozias-Akins
• 金额: $ 113.23万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0115911&HistoricalAwards=false
• 关键词: Aligning; Physical; Functional; Maps; Genomic

Apomixis, defined as asexual reproduction through seed, is widespread among angiosperm families although 75% of the apomictic species are found in three plant families, Poaceae, Rosaceae, and Asteraceae. The plant materials examined in this proposal are members of the Poaceae family, the most important crop plant family in the human food chain. All crop plants in this family reproduce sexually, although wild relatives of maize, wheat, and pearl millet may undergo asexual (apomictic) reproduction. Seeds formed on an apomictic plant contain genetically identical embryos, thus the trait has significant potential for preserving hybrid vigor from one generation to the next in highly productive crop plant genotypes. In Pennisetum squamulatum and Cenchrus ciliaris meiosis typically aborts and unreduced aposporous embryo sacs form from nucellar cells. Genetic mapping studies in Pennisetum have revealed that the locus for the formation of unreduced embryo sacs resides in a chromosomal region with a low recombination rate. Based on genetic map information, positional cloning of gene(s) responsible for apomictic reproduction in Pennisetum is in progress. Transcriptional mapping will use the tools that have been developed for physical mapping of this region and will also use the well developed molecular tools from related diploid model species such as sorghum and rice. The exploration of colinearity in this region between two model diploids and two apomictic species will focus on highly conserved gene sequences. Candidate reproductive or novel genes in this region will be compared for their expression profiles among apomictic and sexual genotypes/species. This research will provide an example of the transfer of genomic information from small-genome grasses to non-recombining regions of large-genome species.

无融合生殖广泛存在于被子植物中，约75%的无融合生殖植物存在于禾本科、蔷薇科和菊科三大科中。本提案中研究的植物材料是禾本科植物家族的成员，禾本科植物家族是人类食物链中最重要的作物家族。在这个科的所有作物植物有性繁殖，虽然玉米，小麦和珍珠粟的野生亲戚可能经历无性（无融合生殖）繁殖。在无融合生殖植物上形成的种子含有遗传上相同的胚，因此该性状具有在高产作物植物基因型中从一代到下一代保持杂种活力的显著潜力。在有鳞狼尾草和蒺藜草中，减数分裂通常中止，珠心细胞形成未退化的无孢子胚囊。狼尾草属植物的遗传作图研究表明，形成未减数胚囊的基因座位于重组率低的染色体区域。 基于遗传图谱信息，目前正在进行狼尾草属植物无融合生殖相关基因的定位克隆。转录作图将使用已经开发的用于该区域物理作图的工具，并且还将使用来自相关二倍体模式物种（如高粱和水稻）的发达的分子工具。在这一区域的两个模式二倍体和两个无融合生殖物种之间的共线性的探索将集中在高度保守的基因序列。将比较该区域的候选生殖或新基因在无融合生殖和有性生殖基因型/物种之间的表达谱。这项研究将提供一个例子，基因组信息从小基因组草的非重组区域的大基因组物种。