Control of barley root growth angle by ENHANCED GRAVITROPISM 2 and associated genes

ENHANCED GRAVITROPISM 2 及相关基因对大麦根生长角度的控制

• 批准号: 430951881
• 负责人: Professor Dr. Frank Hochholdinger
• 金额: --
• 依托单位: Lehrstuhl für Crop Functional Genomics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/430951881?language=en
• 关键词: Control; barley; root; growth; angle

The root growth angle defines how cereal roots grow relative to the gravity vector. The root growth angle is among the most important determinants of root system architecture because it controls water uptake capacity and nutrient use efficiency and as a consequence plant yield. In the first funding period of this project, we cloned the EGT2 gene and demonstrated that it encodes an evolutionary conserved STERILE ALPHA MOTIF domain containing protein. Moreover, we demonstrated in transcriptomic experiments a substantial overlap of genes that are regulated by EGT2 and gravistimulation, suggesting a central role of this gene in controlling the molecular networks determining the root angle in barley. Finally, we demonstrated, that a subset of the genes transcriptionally regulated by gravistimulation and by EGT2 encode proteins that directly interact with EGT2. Based on the results of the first funding period, the overall objective of the second funding period is to obtain a deeper understanding of the EGT2-dependent molecular processes underlying the determination of the root angle of barley seminal roots. Experimentally, we will tackle this objective by three sets of experiments. First, we will study the relationship of the barley seminal root angle with the activity and allelic variation of the EGT2 gene by generating barley lines overexpressing EGT2 and analyzing how EGT2 gene expression control the seminal root angle. In this context, we will also determine how natural allelic variation of EGT2 modulates the root angle of the corresponding barley haplotypes. In a second set of experiments, we will survey the role of auxin in the EGT2 mediated control of the root angle in barley by generating three barley lines containing translational fluorescent fusion proteins of the auxin efflux carriers HvPIN3 and HvPIN4 and the auxin influx carrier HvLAX1 all regulated by EGT2 and by gravistimulation. Goal of this experiment is to study the activity and tissue and cell-type specific accumulation of these marker proteins in gravistimulated wild type and mutant egt2 roots. Furthermore, we will analyze tilling mutants of HvPIN3, HvPIN4 and HvLAX1 and double mutants of these genes with egt2. Finally, we will study the expression of these auxin-transport genes and EGT2 in all single and double mutants with reference to wild type roots. In the third set of experiments we will functionally characterize mutants of the genes OMT, GXM and HMT which encode proteins that directly interact with EGT2 and generate and analyze double mutants of these genes with egt2. Finally, we will survey the expression of these genes and of EGT2 in the mutant egt2 and the single and double mutants generated with reference to wild type roots.

根生长角度定义谷类根相对于重力向量的生长方式。根生长角是决定根系构型的最重要因素之一，因为它控制着水分吸收能力和养分利用效率，从而控制植物产量。在这个项目的第一个资助期，我们克隆了EGT2基因，并证明了它编码了一个进化保守的包含不育的Alpha基序结构域的蛋白质。此外，我们在转录学实验中证明了受EGT2和重力刺激调控的基因有很大的重叠，这表明该基因在控制大麦根角的分子网络中发挥着核心作用。最后，我们证明，受重力刺激和EGT2转录调控的基因子集编码与EGT2直接相互作用的蛋白质。根据第一个资助期的结果，第二个资助期的总体目标是更深入地了解大麦种子根根角确定的基础上依赖于EGT2的分子过程。在实验方面，我们将通过三组实验来实现这一目标。首先，我们将通过构建高表达EGT2的大麦品系，并分析EGT2基因表达是如何控制种子根角的，来研究大麦种子根角与EGT2基因活性和等位基因变异的关系。在此背景下，我们还将确定EGT2的自然等位基因变异如何调节相应大麦单倍型的根角。在第二组实验中，我们将通过产生三个大麦品系来研究生长素在EGT2介导的大麦根角控制中的作用，这些大麦品系包含生长素外流载体HvPIN3和HvPIN4以及生长素内流载体HvLAX1的翻译荧光融合蛋白，这些融合蛋白都受EGT2和重力刺激的调节。本实验的目的是研究这些标记蛋白在重力刺激的野生型和突变型egt2根中的活性和组织和细胞类型的特异性积累。此外，我们还将分析HvPIN3、HvPIN4和HvLAX1的分蘖突变以及这些基因与egt2的双重突变。最后，我们将以野生型根为参照，研究这些生长素运输基因和EGT2在所有单突变体和双突变体中的表达。在第三组实验中，我们将从功能上表征OMT、GXM和HMT基因的突变，这些基因编码与EGT2直接相互作用的蛋白质，并产生和分析这些基因与egt2的双突变。最后，我们将调查这些基因和EGT2在突变体egt2以及参照野生型根产生的单突变体和双突变体中的表达情况。