The function of small RNAs in the nitrogen response

描述(申请人提供)：我们的长期目标是了解氮(N)信号如何控制植物的氮同化、生长和发育。识别参与调节氮素同化的关键成分为提高植物的氮素利用效率或改变种子的氨基酸含量提供了机会，这对健康、农业和人类营养都是重要的问题。该方案中的实验应该能够在分子水平上深入了解植物如何感知和响应N，特别是通过microRNAs(MiRNAs)和其他小RNAs(SRNAs)对基因表达的转录后控制。识别参与调控基因网络以响应N处理的sRNAs可以确定通过特定sRNAs的异位表达或错误表达来优化N同化的机制。现在已经很清楚，miRNAs是动植物调控网络的关键组成部分，但它们在调节靶基因的N-反应中的作用还没有被解决。我们建议(1)识别受N处理调控的miRNAs和其他sRNAs；(2)识别受这些N调控的sRNAs控制的基因网络；(3)了解sRNAs在网络中介导靶基因的N反应中的功能作用。我们的实验方法将是从用无机氮源瞬时处理的植物中分离sRNA，使用454技术对sRNA进行测序，并将这些样本中的转录频率与模拟处理植物中的频率进行比较。我们将把已知和新颖的sRNA：RNA相互作用结合到我们现有的基因网络模型中，以识别由N-响应性sRNA控制的子网络。我们将使用反向遗传和基因组方法来评估特定的sRNAs在植物对N处理的反应中的作用。该项目与Coruzzi博士的团队合作，将生物信息学和基因组学方法结合起来进行功能研究，将极大地加强Gutiirz博士在智利和南美洲的研究计划的研究能力。这些领域的专业知识对于后基因组时代具有竞争力的研究项目至关重要，在智利和南美，这是一个不发达的研究领域。大部分研究将在智利Catslica大学与Rodrigo Gutirez博士合作进行，作为NIH向Gloria M.Coruzzi博士提供的2R01GM032877-21号补助金的延伸。这一提议应该能在分子水平上洞察植物如何感知氮素并对其做出反应。识别参与调节氮同化的关键成分为提高植物氮素利用效率或改变种子的氨基酸含量提供了机会，这些都是对健康、农业和人类营养的重要问题。

DESCRIPTION (provided by applicant): Our long-term goal is to understand how nitrogen (N) signaling controls plant N-assimilation, growth and development. Identifying key components involved in regulating N-assimilation offers opportunities for improving N-use efficiency in plants or modifying the amino acid content of seeds, which are important issues for health, agriculture and human nutrition. The experiments in this proposal should provide insight into how plants sense and respond to N at the molecular level, specifically through the post transcriptional control of gene expression by microRNAs (miRNAs) and other small RNAs (sRNAs). Identifying the sRNAs involved in regulation of gene networks in response to N-treatment could identify mechanisms which may be altered to optimize N-assimilation via the ectopic expression or misexpression of specific sRNAs. It is now clear that miRNAs are key components of regulatory networks in plants and animals, but their role in mediating the N- response of target genes has not been addressed. We propose to (1) Identify the miRNAs and other sRNAs whose expression is regulated by N-treatments; (2) Identify the gene networks that are controlled by these N- regulated sRNAs; and (3) Understand the functional role of sRNAs in mediating the N-response of target genes in the network. Our experimental approach will be to isolate sRNAs from plants treated transiently with inorganic N sources, sequence the sRNAs using 454 technology, and compare the frequency of transcripts in these samples with the frequency in samples from mock-treated plants. We will incorporate known and novel sRNA:RNA interactions into our existing gene network models to identify subnetworks that are controlled by N- responsive sRNAs. We will use reverse genetic and genomic approaches to evaluate the role of specific sRNAs in the plant response to N-treatments. The combination of bioinformatic and genomic approaches for functional studies in this project performed in collaboration with Dr. Coruzzi's group, will greatly strengthen the research capability of Dr. Gutiirrez research program in Chile and South America. Expertise in these areas is essential for competitive research programs in the post-genomic era, and it is an underdeveloped area of research in Chile and South America. Most of the research will be carried out in Chile at P. Universidad Catslica de Chile in collaboration with Dr. Rodrigo Gutiirrez, as an extension of NIH grant #2R01GM032877- 21 to Dr. Gloria M. Coruzzi. This proposal should provide insight into how plants sense and respond to nitrogen at the molecular level. Identifying key components involved in regulating nitrogen assimilation offers opportunities for improving nitrogen-use efficiency in plants or modifying the amino acid content of seeds, which are important issues for health, agriculture and human nutrition.