Functional characterization of Fe-dependent mechanisms promoting the stimulation of adventitious root formation in petunia cuttings

不定根的形成是重要作物无性繁殖的前提条件，也是保持后代遗传一致性的常用手段。随着无土培养基在高通量繁殖中的使用越来越多，以及对可持续园艺实践需求的不断增长，深入了解矿物质营养在AR形成中的作用对于改进现有的繁殖方案至关重要。我们以前的工作表明，铁是AR形成的最具限制性的营养物质，并提供了令人信服的证据，铁在刺激分生组织细胞分裂的独特的未开发的作用，与其在分生组织细胞的细胞核中的高积累。该项目旨在研究铁刺激AR形成的生理和生化机制，并确定可用于改善AR形成的基因。最初，一个详细的细胞生物学分析和超微结构定位的铁将定义的主要解剖和生理过程后，铁的应用。使用RNAseq和基于MS的核仁蛋白分析的全面转录组分析将鉴定参与Fe加速AR形成的基因和蛋白。来自蛋白质组学和转录组学研究的顶级候选基因的功能将使用解剖学和生理学方法在转座子插入或CRISPR/Cas9修饰的转基因植物中进行表征。最后，将在野生矮牵牛登录系、密切相关的茄科属如番茄基因库中研究铁依赖性AR的形成，以更好地获得额外的突变体和园艺作物的几个商业品种。本研究将有助于深入了解植物细胞核中铁的独特功能，并为营养繁殖作物铁营养的有针对性开发奠定基础

Adventitious root (AR) formation is prerequisite for vegetative propagation of important crops and common practice to maintain the genetic identity among progenies. With increasing use of soil-free media in high-throughput propagation and growing demand for sustainable horticultural practices, a deep understanding of the role of mineral nutrition in AR formation is essential for the improvement of existing propagation protocols. Our previous work demonstrated that Fe is the most limiting nutrient for AR formation and provided compelling evidence for a unique unexploited role of Fe in stimulation of meristematic cell division, associated with its high accumulation in the nuclei of meristematic cells. The proposed project aims to study the physiological and biochemical mechanisms underlying Fe-stimulated AR formation and to identify genes that can be used to improve AR formation. Initially, a detailed cell biological analysis and ultrastructural localization of Fe will define the major anatomical and physiological processes upon Fe application. A comprehensive transcriptome profiling using RNAseq and MS-based analysis of nucleolar proteins will identify genes and proteins involved in Fe-accelerated AR formation. The function of top candidate genes derived from proteomic and transcriptomic studies will be characterized in transposon-insertion or CRISPR/Cas9-modified transgenic plants using anatomical and physiological approaches. Finally, the Fe-dependent AR formation will be studied in wild petunia accession lines, closely related Solanaceae genera such as tomato gene pool for a better access to additional mutants and several commercial cultivars of horticultural crops. The proposed study will advance the understanding of the unique function of Fe in the plant nucleolus and will pave the ground for a targeted exploitation of Fe nutrition in vegetative propagated crops