Evolution of Vegetative Phase Change in the Acacieae

这项建议探讨了在金合欢族，一个大的，抗旱，固氮豆类部落的营养阶段变化的演变。这一组包括只产生二回羽状复叶的属，以及一个最近进化的属（金合欢属），它最初产生复叶，但随后转变为产生一个称为叶状体的单叶。在金合欢树内筑巢的是一组约70种（Botrycephalae），只产生复叶。长期以来，人们一直认为这些物种代表了衍生？年轻化了叶状物种的形式，但没有证据支持这一结论。 营养发育的幼年期由高水平的miRNAs miR 156和miR 157指定。该项目的工作假设是葡萄头菌科通过miR 156和/或miR 157的长期高表达而从叶状物种中产生。为了获得支持或反对这一假设的初步证据，将使用北方分析在几个叶状和二羽状的金合欢属物种中检查成熟的miR 156/miR 157转录物的表达。编码miR 156/miR 157的基因将通过下一代测序来自代表性叶状和二羽状物种的基因组DNA来鉴定。这将使得有可能测试通过qRT-PCR检测特定miR 156/mIR 157基因表达的可行性。这些实验的结果将提供？概念验证为未来的建议，旨在确定在金合欢族少年和成年性状的表达变化的分子基础。更广泛的影响一个关于相变的展览将为一年一度的费城科学嘉年华，在本富兰克林百老汇举行。 这个展览的目的是教参加这个狂欢节的许多孩子，植物是动态的，随着它们的生长而变化。与会者将被要求找到少年和成年常春藤和玉米叶片之间的所有差异，并将介绍相思树和桉树的相变。用35 S：：miR 156转化的拟南芥植物将用于说明单个基因如何改变芽的整个结构。

This proposal explores the evolution of vegetative phase change in the Acacieae, a large, drought-resistant, tribe of nitrogen-fixing legumes. This group includes genera that produce only bipinnately compound leaves, and a more recently evolved genus (Acacia) that initially produces compound leaves, but then switches to the production of a simple leaf called a phyllode. Nested within Acacia is a group of approximately 70 species (Botrycephalae) that produce only compound leaves. It has long been assumed that these species represent derived ?juvenilized? forms of phyllodinous species, but there is no evidence for this conclusion. The juvenile phase of vegetative development is specified by high levels of the miRNAs, miR156 and miR157. The working hypothesis of this project is that the Botrycephalae arose from phyllodinous species by the prolonged, high expression of miR156 and/or miR157. To obtain preliminary evidence for or against this hypothesis, the expression of the mature miR156/miR157 transcripts will be examined in a few phyllodinous and bi-pinnate species of Acacia, using Northern analysis. The genes that encode miR156/miR157 will be identified by next-generation sequencing genomic DNA from a representative phyllodinous and bi-pinnate species. This will make it possible to test the feasibility of examining the expression of specific miR156/mIR157 genes by qRT-PCR. The results of these experiments will provide the ?proof-of-concept? for a future proposal aimed at determining the molecular basis for variation in the expression of juvenile and adult traits in the Acacieae. Broader ImpactAn exhibit on phase change will be created for annual Philadelphia Science Carnival, held on the Ben Franklin Parkway. The goal of this exhibit will be to teach the many children who attend this carnival that plants are dynamic, and change as they grow. Attendees will be asked to find all the differences between juvenile and adult ivy and corn leaves, and will be introduced to phase change in Acacia and Eucalyptus. Arabidopsis plants transformed with 35S::miR156 will be used to illustrate how a single gene can change the entire architecture of the shoot.