Role of microRNA-related Polymorphisms in Regulating Heterotic Gene Expression

皮：李磊（美国弗吉尼亚大学）杂种优势（杂种优势）是指不同近交亲本的后代表现出比两亲本中的任何一方优越的性状的现象。这一现象在植物育种和作物改良中得到了广泛的利用。尽管一些遗传概念长期以来被用来解释杂种优势，但它们尚未与分子原理联系起来，因此提供的机制见解有限。本项目的目的是研究调控许多植物发育过程的microrna介导的基因回路在水稻植株杂种优势中的作用。这项工作将利用水稻基因组序列、高通量实验技术、生物信息学工具和分子技术来研究1)两个亲本水稻品系之间的microRNA相关多态性如何影响其杂交后代的差异基因表达，以及2)操纵关键microRNA基因的表达水平是否影响杂种表型。通过本项目将鉴定出一组与杂种优势相关的microRNA基因及其靶基因。从这项研究中获得的知识应该为理解microrna介导的分子事件在杂种优势表达中的作用提供必要的框架，从而为进一步在作物改良中设计这种现象奠定基础。该项目的广泛影响部分源于杂交作物生产的产量优势和其他优越性状。了解microrna调控的基因回路在模式植物水稻杂种优势中的作用，对全球粮食安全具有重要意义。通过已建立的microRNA数据库（http://microrna.sanger.ac.uk/）和水稻注释数据库（http://rice.plantbiology.msu.edu/），将向公众提供一套经过实验测试的水稻microRNA基因。这些信息将为microrna介导的基因调控提供新的见解，并增加我们对植物基因组表达和调控的一般认识。鉴于水稻是禾本科物种的模型，从该项目中获得的信息应该有助于旨在追踪其他粮食、饲料和能源作物中microrna调控基因回路进化的比较基因组学研究。该项目的广泛影响还包括在植物基因组学和生物信息学跨学科领域提供良好的培训机会。通过将课堂讲授与计算实验相结合，该项目产生的信息将特别有助于鼓励本科生积极参与独立研究。

PI: Lei Li (University of Virginia)Heterosis (hybrid vigor) refers to the phenomenon that progeny of diverse inbred parent exhibits superior traits to either of the two parents. This phenomenon has been extensively exploited in plant breeding and crop improvement. Although several genetic concepts have long been used to explain heterosis, they are not yet connected with molecular principles and thus offer limited mechanistic insight. The goal of this project is to investigate the role of microRNA-mediated gene circuits, which regulate many plant developmental processes, in heterosis in the rice plant. This work will utilize the rice genome sequences, high throughput experimental techniques, bioinformatic tools, and molecular techniques to examine 1) how microRNA-related polymorphisms between two parental rice strains contribute to differential gene expression in their hybrids, and 2) whether manipulation the expression levels of key microRNA genes impacts heterotic phenotypes. Through this project, a set of microRNA genes and their target genes involved in heterosis will be identified. Knowledge gained from this research should provide a framework necessary to understand the role of microRNA-mediated molecular events in the expression of heterosis and thus a foundation for further engineering the phenomenon in crop improvement. The broader impacts of this project stem in part from the yield advantage and other superior traits of hybrid-based crop production. Understanding the contribution of microRNA-regulated gene circuits to heterosis in the model plant rice is of great importance to food security worldwide. A comprehensive set of experimentally tested microRNA genes in rice will be made available to the public through established microRNA databases (http://microrna.sanger.ac.uk/) and rice annotation databases (http://rice.plantbiology.msu.edu/). Such information will provide new insights into microRNA-mediated gene regulation and add to our general knowledge of plant genome expression and regulation. Given that rice is a model for the grass species, information obtained from this project should facilitate comparative genomics studies aimed at tracing evolution of microRNA-regulated gene circuits in other food, feed and energy crops. The broader impacts of this project also include excellent training opportunities in the interdisciplinary field of plant genomics and bioinformatics. By blending classroom lectures with computational experimentation, information generated from this project will be particularly useful to encourage undergraduate students to actively participate in independent research.