Dissecting the role of root exudates in root density growth responses in plants

植物可以探测根际的根密度，并利用这些信息来确定根和梢生长的时空分布。植物检测和响应根密度的机制尚不清楚，但生化根渗出物可能起重要作用。独角甾内酯是抑制根和芽系统生长的激素，但也会渗出到土壤中；因此，它们是根密度感知的极好候选信号分子。评估独角甾内酯在根密度感知和反应中的作用。鉴定在根际植物通讯中起作用的新分泌物。了解植物对高根密度的反应机制。虽然植物根际通讯是一个长期以来公认的现象，但很少有研究揭示其背后的分子信号传导机制。因此，这个项目代表了对一种重要生物现象的一种新的研究方式。在农业环境下，高根密度对茎部生长的抑制可能是作物产量的主要限制因素。因此，这个项目非常及时，因为了解这一现象可以解锁产量的快速增长。为了评估独脚金内酯在根密度感知中的作用，我们将利用现有的分子遗传学工具对模式植物拟南芥和作物品种豌豆和大麦进行研究，包括独脚金内酯突变体和报告系。为了鉴定调节植物间通讯的新分泌物，我们将收集大麦的分泌物并对其进行分馏，并使用质谱法鉴定可能的候选信号分子。为了了解植物响应这些信号的机制，我们将筛选大麦多样性面板，对调节根密度响应的基因进行QTL定位。然后我们将识别和描述这些基因的功能。

BackgroundPlants can detect the density of roots in the rhizosphere and use this information to determine the spatio-temporal allocation of root and shoot growth. The mechanisms by which plants detect and respond to root density remain unclear, but biochemical root exudates are likely to play an important role. Strigolactones are hormones that inhibit root and shoot system growth, but which are also exuded into the soil; they are therefore an excellent candidate signalling molecule for root density perception.Objectives1. Assess the role of strigolactones in root density perception and response.2. Identify novel exudates that act in plant communication in the rhizosphere.3. Understand the mechanisms by which plants respond to high root density.NoveltyAlthough plant communication in the rhizosphere is a long-recognized phenomenon, very little work has been undertaken to uncover the molecular signalling mechanisms that underlie it. This project thus represents a novel line of investigation into an important biological phenomenon. TimelinessInhibition of shoot growth by high root density in agricultural contexts likely acts as a major limit on crop yield. This project is thus highly timely, as understanding this phenomenon could unlock rapid increases in yield.Experimental ApproachTo assess the role of strigolactone in root density perception, we will use existing molecular genetic tools in the model plant Arabidopsis and in the crop species pea and barley, including strigolactone mutants and reporter lines. To identify new exudates that regulate plant-plant communication, we will collect exudates from barley and fractionate them, and use mass spectrometry to identify possible candidate signalling molecules. To understand the mechanisms by which plants to respond these signals, we will screen a barley diversity panel to perform QTL mapping for genes that regulate the response to root density. We will then identify and characterise the function of these genes.