Interaction of auxin and strigolactone in the regulation of carpic dominance

众所周知，植物繁殖过程中产生的种子可以相互交流，而年龄较大/生命力较强的果实中的种子能够限制或中止新果实/种子的发育。驱动这一现象的机制（“carpic优势”）尚不清楚，但初步数据表明植物激素独角麦内酯和生长素起关键作用。分析独脚金内酯和生长素在cartic显性中的作用。确定导致carpic优势的转录反应。定义调节作物种类中carpic优势的环境信号。新颖性虽然carpic显性现象早已被认识到，但很少有研究，特别是在分子遗传学时代。因此，该项目代表了植物发育生物学的一个高度新颖的领域。我们迫切需要提高农作物产量来养活不断增长的全球人口。因此，这个项目非常及时，因为carpic优势是种子结实率的主要限制，了解它可以解锁产量潜力的快速增长。为了确定独角麦内酯和生长素在cartic显性中的作用，我们将利用现有的模式植物拟南芥的分子遗传学工具，包括生长素/独角麦内酯突变体和报告系。我们还将在作物番茄（具有很强的carpic优势）中开发工具，以在果实发育过程中对生长素/独脚金内酯动态进行实时成像。我们将使用RNA-seq来鉴定在carpic显性和显性果实/种子中发生的转录变化，然后使用反向遗传分析来测试鉴定的候选基因在这种现象中的作用。我们还将对作物物种油菜（拟南芥的近亲）进行田间和温室试验，以确定调节carpic优势程度的环境信号，并将拟南芥中产生的知识转移到田间/农业环境中。本项目旨在了解植物中腐肉优势现象的生化、遗传和细胞机制。因此，它深深植根于分子和细胞水平的机械生物学。该项目非常适合农业和粮食安全研究领域的职责范围。全球粮食安全将需要增加主要作物品种的产量，而cartic的优势对许多这些作物品种的产量起着主要限制作用。如果我们能够了解carpic优势的机制基础，我们就可以培育出carpic优势降低的作物品种，这可能导致产量的阶梯式变化，而不需要更多的集约化投入（如化肥）。

BackgroundSeeds produced during plant reproduction are known to communicate with each other, and seeds in older/more vigorous fruits are able to limit or abort the development of new fruits/seeds. The mechanisms that drive this phenomenon ('carpic dominance') are poorly characterised, but preliminary data suggest the phytohormones strigolactone and auxin play key roles.Objectives1. Analyse the role of strigolactone and auxin in carpic dominance.2. Identify transcriptional responses that result in carpic dominance.3. Define environmental signals that modulate carpic dominance in crop species.NoveltyAlthough the phenomenon of carpic dominance is long-recognized, very little work has been undertaken, especially in the molecular genetic era. This project thus represents a highly novel area in plant developmental biology. TimelinessThere is a pressing need to increase crop yields to feed an expanding global population. This project is thus exceptionally timely, since carpic dominance is a major limit on seed set, and understanding it could unlock rapid increases in yield potential.Experimental ApproachTo define the role of strigolactone and auxin in carpic dominance, we will exploit existing molecular genetic tools in the model plant Arabidopsis, including auxin/strigolactone mutants and reporter lines. We will also develop tools in the crop plant tomato (which has strong carpic dominance) to perform live imaging of auxin/strigolactone dynamics during fruit development. We will use RNA-seq to identify transcriptional changes that occur in both dominant and dominated fruit/seeds during carpic dominance, and will then test the role of identified candidate genes in the phenomenon using reverse genetic analyses. We will also use both field and glasshouse experiments in the crop species oilseed rape (a close relative of Arabidopsis), to identify the environmental signals that modulate the extent of carpic dominance, and to transfer knowledge generated in Arabidopsis to field/agricultural contexts.This project aims to understand the biochemical, genetic and cellular mechanisms that form the basis of the carpic dominance phenomenon in plants. It is therefore deeply rooted in mechanistic biology at the molecular and cellular level. The project is an excellent fit with the remit of the agriculture and food security research area. Global food security will require increased yield from major crop species, and carpic dominance acts as a major limit on yield in many of these species. If we can understand the mechanistic basis of carpic dominance, we can breed crop species with reduced carpic dominance, which could result in a step-change in yield, without the need for more intensive inputs (e.g. fertilizer).