Mechanisms regulating the boron nutritional status in rapeseed and Arabidopsis and their implications for the development of boron-efficient genotypes

硼(B)是植物必需的微量元素。尽管使用了现代的施肥方法，缺硼仍然会造成农业植物生产的损失。尽管已经报道了B对植物生长和生理的积极影响，但大多数B的功能和控制B营养状态的调控机制仍然不清楚。本项目的主要目的是阐明对B高度缺乏敏感的油菜植物在营养和生殖生长过程中如何处理和调节它们的B状态。在此背景下，该项目旨在确定B在调节B状态本身的机制中的作用模式，并揭示在不同基因类型中影响B效率的机制和潜在基因。被调查的植物物种是在农学上重要的作物油菜(Brassica Napus)及其近亲模式植物拟南芥(Arabiopsis Thaliana)。本项目范围内解决的问题应有助于从整个植物水平到细胞水平详细了解控制B的吸收和分配的机制。类结节蛋白(NIPs)属于水通道蛋白家族，对B的吸收和分布起着至关重要的作用。对甘蓝型油菜NIP分子和生理特性的系统研究将阐明它们在B运输中的作用，并将识别在B反应网络中发挥关键作用的新的NIP相关机制。为了进一步解决大多数未知的B营养状况对基因调控和代谢的影响，将对B充足和B缺乏油菜植株进行RNA测序。这将识别未知的B反应基因，这些基因在信号通路、B依赖的分化过程和调节B稳态的机制中发挥关键作用。将进行QTL定位(在B效率不同的基因型之间杂交产生的DH油菜群体上)和GWAS分析(基于拟南芥加入小组的数据)，这些信息将分别用于鉴定油菜和拟南芥耐缺硼的座位和基因。硼酸和亚砷酸(AS)共享相同的NIP介导的运输途径。为了评估是否有可能设计针对B的NIP通道，以产生低浓度有毒As矿物的作物，我们将详细研究影响类金属运输选择性的NIP通道特性。本项目旨在产生关于控制B稳态的调节机制和潜在基因的原始知识。该项目将有助于改善田间的硼管理，优化与作物相关的农艺性状，并培育耐缺硼基因。

Boron (B) is an essential microelement for plants. Despite the use of modern fertilization methods, B-deficiency still causes losses in agricultural plant production. Even though many positive effects of B on plant growth and physiology have been reported, a large majority of B functions and the regulatory mechanisms controlling the B nutritional status remain unknown.The main objective of this project is to elucidate how the greatly B-deficiency-sensitive Brassica crop plants process and regulate their B status during vegetative and reproductive growth. In this context, the project aims at identifying the mode of action of B in mechanisms regulating the B status itself and at uncovering those mechanisms and underlying genes contributing to B-efficiency in different genotypes.Plant species subjected to investigation are the agronomically important crop plant Brassica napus (rapeseed) and its close relative the model plant Arabidopsis thaliana.Questions addressed within the scope of this project should lead to a detailed understanding of mechanisms controlling B uptake and allocation from the level of the whole plant down to the cellular level. Nodulin26-like Intrinsic Proteins (NIPs), which belong to the aquaporin protein family, are essential for B uptake and distribution. The systematic focus on the molecular and physiological characterization of B. napus NIPs will clarify their role in B transport and will identify novel NIP-associated mechanisms playing key roles in the B response network. To further resolve the mostly unknown impact of the B nutritional status on gene regulation and metabolism, RNA-sequencing will be performed on B-sufficient and B-deficient rapeseed plants. This will identify yet unknown B-responsive genes playing key roles in signalling pathways, B-dependent differentiation processes and mechanisms regulating the B homeostasis. QTL mapping (on a generated DH rapeseed population deriving from a cross between genotypes with contrasting B-efficiencies) and GWAS analyses (on data of an Arabidopsis accession panel) will be performed and the information will be used to identify loci and genes which are responsible for B-deficiency tolerance in rapeseed and Arabidopsis, respectively.Boric acid and arsenous acid (As) share the same NIP-mediated transport pathways. To assess whether it is possible to design B-specific NIP channels in order to generate crops with low concentrations of the toxic As mineral, we will investigate NIP channel characteristics which have an influence on metalloid transport selectivity in detail.This project has been designed to generate original knowledge on regulative mechanisms controlling the B homeostasis and on underlying genes. This project promises to contribute to the improvement of B management in the field, the optimization of agronomically relevant plant traits and the development of B-deficiency-tolerant genotypes.