Analysis of mitochondria to nucleus signaling affecting flower development in carrot

植物中的突变可以导致花的形态或同源分裂的改变。例如，花瓣可以被萼片取代，产生花粉的雄蕊可以被花瓣取代。拟南芥已经推导出了花发育的全面核遗传模型，关键基因的同源基因可以在其他物种中确定。胡萝卜中观察到同源表型，但与拟南芥中的核基因控制不同，胡萝卜中的突变受细胞质因子的制约，很可能是在线粒体中。细胞质同源异体的出现表明，细胞质同源信号在花的发育中发生。胡萝卜可以作为一种新的模式系统，因为在自然种群和自交系中进化的同源异型具有明显的核质相互作用：用花瓣代替雄蕊，或者用苞片状器官代替花瓣和雄蕊。胡萝卜的表型是由两个核型与一个细胞质连接相互作用的结果。但在其他物种中，花发育的细胞质调控是通过回交进入异质或原生质融合而产生的，与特定的细胞质-核相互作用相关的不同表型观察不清楚。这项研究的长期目标是发现影响花发育的线粒体到核信号的所有重要遗传成分。最终，该研究计划可以直接将线粒体因子的表达与拟南芥花发育模型中的基因的同源基因联系起来，促进一个新兴植物生物学领域的基础知识。短期内，将在细胞质突变株系和野生型胡萝卜品系的花分生组织中研究与氧化还原相关的基因，并评估差异基因表达。

Mutations in plants can lead to altered flower morphologies, or homeosis.  For example, petals can be replaced by sepals and pollen-producing stamens can be replaced by petals.  A comprehensive nuclear genetic model for flower development has been derived for Arabidopsis, and orthologues of critical genes can be identified in other species.Homeotic phenotypes are observed in carrot, but in contrast to nuclear gene control in Arabidopsis, the mutation in carrot is conditioned by a cytoplasmic factor, likely in the mitochondrion.  The occurrence of  cytoplasmic homeosis suggests that cytoplasmic-nuclear signaling occurs in flower development. The research proposed here will work towards the development of a genetic pathway for this process, which has not been elucidated in any plant species.Carrot can serve as a novel model system because the cytoplasmically-controlled homeotic phenotypes evolved in natural populations and inbred lines are available with distinct nuclear-cytoplasmic interactions: the replacement of stamens with petals, or both petals and stamens with bract-like organs.  The phenotypes result from two nuclear genotypes interacting with one cytoplasmic accession.  In other species, the cytoplasmic regulation of flower development results from backcrossing into alien cytoplasms or protoplast fusion, and distinct phenotypes related to specific cytoplasmic-nuclear interactions are not clearly observed, as in carrot.The long-term objective of this research is to discover all the genetic components important for mitochondria to nucleus signaling affecting flower development.  Ultimately, the research program could directly link expression of a mitochondrial factor to orthologs of genes in the Arabidopsis floral development model, advancing basic knowledge in an emerging area of plant biology.  In the short term, genes related to redox will be studied, and differential gene expression assessed, in floral meristems of cytoplasmic mutant and wild type carrot lines.