Collaborative Research: Conservation and Diversification of Regulatory Pathways Controlling Stem Cell Proliferation

干细胞进行自我更新以产生更多的干细胞，并产生子细胞，子细胞继续产生多种专门的细胞类型。在植物中，茎顶端分生组织（SAM）的细胞起干细胞的作用，产生更多的干细胞以及专门的细胞类型，从而形成叶、枝和果实。本研究调查的基础上，刺的发展，柑橘作为一种手段，了解如何终止干细胞增殖的控制。刺来自SAM细胞，它们不能自我更新，而是终末分化，这为探索SAM细胞增殖是如何控制的提供了一个独特的机会。柑橘是探索这个问题的一个很好的研究系统，因为许多柑橘物种都有刺，并且存在多种遗传和基因组工具来研究柑橘。在这项研究中，从柑橘候选基因已涉及在调节干细胞增殖将检查其作用，在刺的发展，使用表达分析和采用新开发的转基因方法。在一组互补的实验中，将通过对有刺与无刺柑橘物种的转录组进行全基因组比较来鉴定参与干细胞增殖停滞的关键基因。这些分析将开始定义干细胞停滞的重要过程。 他们还将阐明干细胞维持和分化的保守和新机制。柑橘植物生长、果实产量和收获成本都受到刺的影响，因此了解如何控制刺的产生将极大地影响这种有价值的水果作物的经济效益。作为该项目的一部分，一名博士后助理、一名研究生和三名本科生将接受培训。 此外，将在康涅狄格州纽黑文的沼泽植物园举办柑橘生物学展览，旨在提高公众对科学的认识和理解。

Stem cells undergo self-renewal to produce more stem cells, as well as to produce daughters that go on to produce multiple specialized cell types. In plants, cells of the shoot apical meristem (SAM) act as stem cells, giving rise to more stem cells as well as specialized cell types contributing to the leaves, branches and fruit. This study investigates the basis for thorn development in Citrus as a means to understand how the termination of stem cell proliferation is controlled. Thorns arise from SAM cells that fail to self-renew, and instead terminally differentiate, providing a unique opportunity to explore how SAM cell proliferation is controlled. Citrus is an excellent study system to explore this question as many Citrus species possess thorns, and multiple genetic and genomic tools exist for work with Citrus. In this study, candidate genes from Citrus that have been implicated in regulating stem cell proliferation will be examined for their roles in thorn development using expression analyses and employing newly developed transgenic approaches. In a complementary set of experiments, key genes involved in the arrest of stem cell proliferation will be identified via genome-wide comparisons of the transcriptomes of thorned vs. thornless Citrus species. These analyses will begin to define the processes important for stem cell arrest. They will also elucidate conserved and novel mechanisms of stem cell maintenance and differentiation. Citrus plant growth, fruit yield and harvest costs are all affected by thorniness, so understanding how to manipulate thorn production will greatly impact the economics of this valuable fruit crop. A postdoctoral associate, a graduate student and three undergraduates will receive training as a part of this project. In addition, a display of Citrus biology will be mounted at the Marsh Botanical Gardens, NewHaven, CT, aimed at promoting public awareness and understanding of science.