Analysis of mitochondria to nucleus signaling affecting flower development in carrot

植物的突变可以导致花形态的改变，或同源性。例如，花瓣可以被萼片代替，产生花粉的雄蕊可以被花瓣代替。一个完整的拟南芥花发育的核遗传模型已经被推导出来，关键基因的同源物可以在其他物种中被鉴定出来。在胡萝卜中观察到同型表型，但与拟南芥的核基因控制相反，胡萝卜中的突变是由细胞质因子调节的，可能在线粒体中。细胞质同型分裂的发生表明细胞质核信号在花发育过程中发生。本文提出的研究将致力于开发这一过程的遗传途径，这一途径尚未在任何植物物种中得到阐明。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出的细胞质控制的同型异体表型具有不同的核-细胞质相互作用：雄蕊被花瓣取代，或花瓣和雄蕊都被苞片状器官取代。表型是两个核基因型与一个细胞质连接相互作用的结果。在其他物种中，花发育的细胞质调控是通过回交到外源细胞质或原生质体融合而产生的，并且没有明确观察到与特定细胞质-核相互作用相关的不同表型，如胡萝卜。本研究的长期目标是发现影响花发育的线粒体到细胞核信号传导的所有重要遗传成分。最终，该研究项目可以直接将线粒体因子的表达与拟南芥花发育模型中基因的同源物联系起来，从而推进植物生物学新兴领域的基础知识。在短期内，将研究与氧化还原相关的基因，并评估细胞质突变型和野生型胡萝卜花分生组织中的差异基因表达。

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.