TRMS: An Integrative Study of Plant Mitochondrial Biology

PI: Sally Mackenzie （University of Nebraska）合作者：Alan Christensen (University of Nebraska), Tom Elthon (University of Nebraska), Dong Wang （University of Nebraska）合作者：Andrew Benson （University of Nebraska）植物线粒体基因组在结构和维护特性上经历了许多变化，这些变化使它们与哺乳动物的线粒体基因组区别开。迄今为止，大多数植物基因组都是线性和圆形相互转换分子的复杂集合，显示出重组、外源DNA整合和相对拷贝数变化的证据。这些基因组活动由核基因控制，核基因的表达可以引起线粒体基因组的不稳定。在番茄、烟草、小米、高粱、大豆和拟南芥中使用这种方法可以进行线粒体基因组破坏的跨物种比较。该项目利用该系统来识别直接受线粒体基因组状态影响的细胞和发育途径，这些途径在植物物种中是保守的，并被植物表型的变化所证明。该项目的中心假设认为，植物中的线粒体状态整合到质体发育、花粉发育、细胞周期控制和特定植物胁迫反应的离散途径中。该项目通过结合拟南芥突变分析和跨物种比较以及线粒体和基因表达分析，为这些途径整合点提供了独特的入口。虽然人们早就知道植物线粒体在代谢、生长和发育中发挥着独特的作用，但在这项研究之前，直接的线粒体操作主要局限于抑制剂研究，很难推断出整个植物的表型。研究的更广泛影响。植物线粒体基因组重排可导致具有重要农业意义的植物表型的改变。例如，这些研究已经提供了细胞质雄性不育的证据，这是一种在杂交种子生产和转基因控制中有用的特性，并增强了作物的耐热性。这两种有价值的性状都很难用传统的作物育种方法获得。在培训机会方面，内布拉斯加州大学植物科学创新中心（PSI）赞助了一个整合到拟议项目中的本科生暑期实习计划；通过这个项目，在过去的两年里，已经有四名少数民族学生被研究生项目录取。PSI还指导内布拉斯加州分子植物育种研究生计划；本计划资助至少两名植物育种学生参与拟进行的项目。目前，美国面临着在转基因作物田间管理、基于DNA标记的选择、统计学和比较基因组学方面具有交叉专业知识的植物育种家的严重短缺。该项目与校园和工业界的植物育种家合作，为这种培训提供了肥沃的土壤。项目数据将通过http://psiweb.unl.edu/mackenzie/和基因表达数据发布到ArrayExpress （http://www.ebi.ac.uk/microarray-as/ae/）获取。

PI: Sally Mackenzie (University of Nebraska) CoPIs: Alan Christensen (University of Nebraska), Tom Elthon (University of Nebraska), Dong Wang (University of Nebraska) Collaborator: Andrew Benson (University of Nebraska)Plant mitochondrial genomes have undergone a number of changes in their structure and maintenance properties that distinguish them from their mammalian counterparts. Most plant genomes characterized to date are a complex collection of linear and circular interconverting molecules that display evidence of recombination, foreign DNA integration and changes in relative copy number. These genomic activities are controlled by nuclear genes that can be manipulated in their expression to cause mitochondrial genome instability. Using this approach in tomato, tobacco, millet, sorghum, soybean and Arabidopsis allows for cross-species comparison of mitochondrial genome disruption. This project exploits this system to identify cellular and developmental pathways that are directly influenced by mitochondrial genome status, conserved across plant species, and evidenced by changes in plant phenotypes. The central hypothesis of the project states that mitochondrial status in plants is integrated into discrete pathways for plastid development, pollen development, cell cycle control and particular plant stress responses. The project provides unique entry to these pathway integration points by combining Arabidopsis mutant analysis and cross-species comparisons with mitochondrial and gene expression analysis. While it has long been known that plant mitochondria play distinct roles in metabolism, growth and development, direct mitochondrial manipulations prior to this study were largely restricted to inhibitor studies with limited opportunity for extrapolation to whole plant phenotype. Broader impacts of the study. Plant mitochondrial genome rearrangement can lead to altered plant phenotypes of agricultural importance. For example, these studies have already produced evidence of cytoplasmic male sterility, a trait useful in hybrid seed production and transgene containment, and of enhanced crop thermotolerance. Both valuable traits are difficult to attain using conventional crop breeding approaches. With regard to training opportunities, the Center for Plant Science Innovation (PSI) at University of Nebraska sponsors an undergraduate summer internship program that integrates to the proposed project; through this program, four minority students have already been recruited into graduate programs in the past two years. The PSI also directs the Nebraska Molecular Plant Breeding Graduate Program; this project sponsors at least two plant breeding students on the proposed project. Currently, the US faces a critical shortage of plant breeders with cross-cutting expertise in field management of transgenic crops, DNA marker-based selection, statistics, and comparative genomics. This project provides fertile ground for such training, in cooperation with plant breeders on campus and in industry.Project data will be accessible via http://psiweb.unl.edu/mackenzie/ and gene expression data released to ArrayExpress (http://www.ebi.ac.uk/microarray-as/ae/).