Molecular framework underlying stolon development in strawberry

草莓是一种非常重要的水果作物，对人类营养和农业产量都有贡献。由于目前的草莓品种都是从传统的杂交育种努力中衍生出来的，它们需要通过子代克隆来繁殖，以保持其独特的杂交组合。这些无性系的子代被称为爬行植物，它们是由长而水平的茎茎产生的，这种茎被称为匍匐茎。然而，人们对草莓的匍匐茎形成是如何调控的，以及为什么草莓是少数几种被赋予通过匍匐茎进行无性繁殖的分子机制的植物之一知之甚少。这些实验旨在揭示草莓这一特殊而非常重要的发育特征背后的分子机制。此外，该项目将在批判性思维、沟通以及实验设计和执行方面培训下一代科学家。此外，弗吉尼亚州立大学的一名教授每年夏天将带两名本科生到马里兰大学学习DNA序列分析并进行研究。总体而言，该项目将提供知识库和工具来开启和关闭匍匐茎，从而在开启匍匐茎形成时提高草莓产量，或在关闭匍匐茎形成时提高果实产量。该项目产生的数据，如核糖核酸序列数据和网络分析，将很容易通过网站和公共储存库获取；研究材料将与科学界共享。这一结果将促进对植物发育的基本认识，并为草莓产量的提高提供新的策略。在草莓中，通过匍匐茎进行无性繁殖的有趣模式为研究腋生分生组织细胞命运的决定提供了一个不同寻常的机会，因为每个腋生分生组织要么发育成匍匐茎，要么发育成枝冠(以花为终点的枝条)。以前对二倍体草莓Fragaria Vesca的研究发现，赤霉素的一个关键信号成分FveRGA1是抑制匍匐茎形成的。本实验将首先用CRISPR分离FveRGA1的零等位基因，然后对突变的表型进行鉴定，从而研究FveRGA1是如何通过分离FveRGA1的零等位基因来抑制黑麦草的匍匐茎形成的机制。转录组和共识共表达网络将识别在腋生分生组织中表达的产生匍匐茎的基因。在腋生分生组织中直接与FveRGA1相互作用的蛋白质将通过酵母双杂交筛选和双分子荧光互补确认。已确定的候选基因在匍匐茎发育中的作用将通过RNAi和在转基因F.Vesca中的过度表达来确定。最后，正向遗传方法将被用来定位和分离在匍匐茎形成中具有改变能力的新突变体所定义的基因。这些实验将为研究匍匐茎发育的分子基础提供新的见解，并阐明已鉴定的基因与FveRGA1之间的分子相互作用在控制匍匐茎形成中的机制。抑制匍匐茎产生的能力将最大限度地促进枝冠的形成，导致更多的花朵和更高的果实产量。从这个项目中得到的见解将提供知识和工具来打开和关闭匍匐茎，导致草莓产量和产量的提高。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Strawberry is an immensely important fruit crop contributing to human nutrition and agricultural output. As current strawberry varieties are all derived from traditional crossbreeding efforts, they need to be propagated through daughter clones to preserve their unique hybrid combination. These daughter clones, known as runners, are produced from long and hortizontal stems named stolons. However, little is known about how stolon formation is regulated and why strawberry is one of the few plants endowed with the molecular machinery to conduct asexual reproduction through stolon. The experiments are aimed at revealing the molecular mechanisms that underlie this special and highly important developmental trait of strawberry. Further, the project will train next generation scientists in critical thinking, communication, as well as experimental design and execution. Additionally, a professor at the Virginia State University will bring two undergraduate students to the University of Maryland each summer to learn DNA sequence analysis and conduct research. Overall, the project will provide knowledge base and tools to switch on and off stolon, leading to improved strawberry production when stolon formation is switched on or increased fruit yield when stolon formation is turned off. The data generated from the project such as RNA sequence data and network analyses will be easily accessible through websites and public depository; the research materials will be shared with the scientific community. The results will advance basic understanding of plant development and provide novel strategies in the improvement of strawberry productivity. In strawberry, the interesting mode of asexual reproduction through stolon provides an unusual opportunity to investigate axillary meristem cell fate determination as each axillary meristem either develops into a stolon or a branch crown (a shoot that terminates with flowers). Previous studies using a diploid strawberry Fragaria vesca identified a key signaling component of gibberellin, FveRGA1, as a repressor of stolon formation. The experiments will investigate the mechanism of how FveRGA1 represses stolon formation in F. vesca by first isolating null alleles of FveRGA1 with CRISPR and then characterizing the mutant phenotype. Transcriptome and consensus co-expression networks will identify genes expressed in the axillary meristem that gives rise to stolon. Proteins that directly interact with FveRGA1 in the axillary meristem will be identified through a yeast two-hybrid screen and confirmed by Bimolecular Fluorescence Complementation. The role of identified candidate genes in stolon development will be determined using RNAi and over-expression in transgenic F. vesca. Finally, forward genetic approach will be used to map and isolate genes defined by new mutants with altered ability in stolon formation. These experiments will provide novel insights into the molecular underpinnings of stolon development and illuminate the mechanisms of molecular interaction between the identified genes and FveRGA1 in controling stolon formation. The ablity to suppress stolon production will maximize branch crown formation, leading to more flowers and higher fruit yield. Insights derived from this project will provide knowledge and tools to switch on and off stolon, leading to improved strawberry production and yields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.