Feedback of cell cycle on cell type in Arabidopsis organogenesis

世界将需要大幅提高农业产量，以满足迅速增长的人口对粮食和可再生燃料的需求。几种主要食用植物的可食用部分，包括玉米、水稻、小麦、豆类和豌豆，都经历了一个称为核内复制的特殊过程，在这个过程中，它们的细胞会扩大，DNA含量会增加数倍。尽管核内复制很重要，但人们对核内复制是如何调控的知之甚少，而且在食用植物中很难进行研究，因为核内复制的营养组织深埋在发育中的种子中。为了克服这个困难，这项研究将使用遗传学，细胞生物学和基因组学来研究拟南芥花表面暴露细胞的核内复制。在这个新系统中，细胞可以用于种植植物的实验。特别是，这项研究将解决核内复制如何影响正在经历这一过程的细胞的问题。首先，将使用核内复制细胞数量增加的突变体来阐明核内复制是如何控制的。第二，核内复制关闭一个基因的机制将被确定。通常科学家认为外部信号开启和关闭细胞内的基因。 然而，最近令人兴奋的结果表明，至少在一种情况下，核内复制可以关闭一个基因。最后，为了发现有多少基因被核内复制打开或关闭，将在核内复制细胞和它们的非核内复制邻居之间比较拟南芥基因组中所有基因的表达水平。这项研究的结果可能会显示增加作物产量的新方法。此外，该项目还将培训两名研究生，为三名本科生提供暑期研究机会，并将举办讲习班，使女学生对科学感兴趣。

The world will need to increase agricultural yields dramatically to meet the demands of the rapidly growing population for food and renewable fuel. The edible parts of several major food plants, including corn, rice, wheat, beans, and peas, undergo a specialized process called endoreduplication in which their cells enlarge and increase their DNA content several fold. Despite its importance, little is known about how endoreduplication is regulated, and it is difficult to investigate in food plants because the endoreduplicating nutritive tissues are buried deep within their developing seeds. To overcome this difficulty, the research proposed will use genetics, cell biology, and genomics to investigate endoreduplication in exposed cells on the surface of the Arabidopsis flower. In this new system, the cells are accessible for experimentation in growing plants. In particular, the research will address the question of how endoreduplication influences the cell undergoing the process. First, a mutant with increased numbers of endoreduplicated cells will be used to elucidate how endoreduplication is controlled. Second, the mechanism through which endoreduplication turns off one gene will be determined. Normally scientists think of external signals turning on and off genes within a cell. However, exciting recent results suggests that in, at least one case, endoreduplication can turn off a gene. Finally, to find how many genes are turned on or off by endoreduplication, the expression levels of all of the genes in the Arabidopsis genome will be compared between endoreduplicating cells and their non-endoreduplicating neighbors. Findings from this research may show new ways to increase crop yield. In addition, this project will train two graduate students, provide opportunities for summer research for three undergraduate students, and will enable workshops targeted to interest school girls in science.