水稻二倍体和四倍体杂交的胚乳发育和印记基因分析

项目名称： 水稻二倍体和四倍体杂交的胚乳发育和印记基因分析

项目编号： No.31301049

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 生物科学

项目作者： 张红宇

作者单位： 四川农业大学

项目金额： 23万元

中文摘要： 基因印记是指子代仅表达亲本之一基因拷贝的现象。植物中，印记主要发生在三倍体胚乳中。拟南芥中，印记通过控制胚乳细胞化的时机来调节胚乳发育进程。水稻是重要的粮食作物，胚乳亦是人类食用的主要部分，探索印记基因对胚乳发育的作用显得尤为重要。本研究根据水稻二倍体（2n）和四倍体（4n）正、反交后种子发育存在明显差异且败育这一现象，以前期研究确定的100多个新的印记基因为基础，通过胚乳发育观察、印记基因表达测序、添加DNA甲基化抑制剂等方法，重点研究印记基因在父母本基因组剂量失衡下的表达量变化和印记方式变化，以及降低甲基化水平能否改善胚乳败育。本结果将有助于确定种子败育的原因及方式，印记基因表达与胚乳败育之间的关系，从而为减少异交败育或促进胚乳发育提供参考；也可进一步验证"亲本冲突学说"在水稻中的适用性，为揭示水稻等禾谷类作物印记调控模式奠定重要基础。

中文关键词： 倍性；胚乳；胚；DNA甲基化；印记

英文摘要： Genomic imprinting refers to an epigenetic mechanism by which the selective expression of a parental allele dependents on its parent of origin. Imprinting primarily occurs in the endosperm, a triploid nutritious tissue of flowering plants. In Arabidopsis, imprinting is thought to regulate the timing of cellularisation of endosperm to influence seed size. Rice is one of the most important food crops. Endosperm is the major source for food. It is important to understand the role of imprinted genes in regulating endosperm development. Using the seeds with distinct phenotypes from the reciprocal crosses of diploid (2n) and tetraploid (4n) rice, we will investigate the endosperm and embryo development cytologicaly to understand if imbalanced contributions of maternal and paternal imprinted genes result in different endosperm phenotypes between the 2n and 4n reciprocal crosses. We will also analyse the expression level and imprinting mode of previously identified imprinted genes in the parental genome imbalanced crosses. Seeds from interploidy crosses will be rescued on medium formulated for cereal early seeds by adding DNA methylation inhibitor (5-Azacytidine). This study will illustrate that how expression of imprinted genes is affected and, at to what extent, imprinting will be deregulated in interploidy crosses.

英文关键词： Polyploid；endosperm；embryo；DNA methylation；imprinting