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Developmental roles of miR156/172-regulated transcription factors in barley

大麦中miR156/172调控转录因子的发育作用

基本信息

批准号：
BB/L001934/1
负责人：
Sarah McKim
金额：
$ 43.68万
依托单位：
University of Dundee
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FL001934%2F1
关键词：
Developmental roles miR156 172 regulated

项目摘要

Cereal grain forms the basis of our food supply. During domestication and subsequent breeding, cereal architecture or body plan was often drastically modified to produce plants which produce higher grain yeilds. Growth of flowering plants, including cereals, reflects the progression of growth phases which influence architecture, broadly moving from vegetative juvenile growth to vegetative adult and finally to the reproductive phase. In temperate cereals, vegetative growth involves production of a main shoot giving rise to leaves and additional shoots, while in reproductive phase, shoots form a spike tip on which develop rows of grain. Although produced at the end of the life cycle, grain yield often reflects earlier developmental events. For instance, yield may be affected by the number of shoots which form fertile spikes and/or the amount of photosynthetic energy related to the number of leaves set. To meet the rapid, rising cereal demand, a sophisticated molecular understanding of genes regulating plant architecture is required for breeders to quickly and confidently select for better-performing crops - yet the depth of knowledge about gene function in temperate cereals such as wheat and barley, both dominant global crops, is especially thin, reflecting the traditional recalcitrance of these species to molecular study. However, recent accelerated generation of sophisticated genomic and molecular tools and resources for barley hold great promise to unlock the developmental genetics of temperate cereal architecture by using this crop as a developmental model.My proposed research will capitalize on exciting work in other plant model systems which highlights the role of a conserved developmental phase network in the regulation of multiple yield-related architectural traits. This network is driven by antagonism between two microRNA (miRNA) gene families, miR156 and miR172, which encode short regulatory RNA molecules: miR156 is abundant early in the life-cycle to promote juvenile characteristics, like leaf production, however, over time miR156 levels fall, inhibited by rising levels of miR172, associated with adult and reproductive traits. These miRNAs function through repression of multiple target transcription factors, proteins that themselves regulate genes to control specific developmental traits. My research ambition is to understand which traits are controlled by individual miR156/172-regulated transcription factors in temperate cereals, in particular, barley, and how these factors control gene expression in order to inform future breeding efforts.In fact, I have already found that a gene encoding a miR172-regulated transcription factor in barley is a master regulator of internode elongation in the stem and spike, thereby directly influencing grain density and plant height, both important agronomic traits. Height influences lodging (falling over) of top-heavy, grain-laden crops, making the control of plant height desirable. This gene is the first transcription factor implicated in internode growth in barley and I predict that it functions by controlling the expression of a suite of downstream genes, which could also be potential breeding targets. In this project, I will employ gene expression, biochemical and sequencing techniques to definitively identify these target genes. Moreover, I will examine possible interactions with other pathways involved in internode growth, as a first step towards building a regulatory gene network explaining internode growth. In addition, I will determine where and when other miR156/172-regulated transcription factors in barley are expressed. Finally, I will use powerful transgenic approaches to tease apart individual contributions to other traits controlled by these transcription factors. I anticipate that through this research, new genes involved in important traits for farmers will be identified and characterized, acting to inform crop breeding.

谷物是我们食物供应的基础。在驯化和随后的育种过程中，谷物的结构或身体结构经常被彻底改变，以生产出更高谷物产量的植物。开花植物（包括谷物）的生长反映了影响结构的生长阶段的进展，大致从营养幼体生长到营养成体，最后到生殖阶段。在温带谷物中，营养生长涉及产生主芽，产生叶子和额外的芽，而在繁殖阶段，芽形成穗尖，在穗尖上长出成排的谷物。尽管是在生命周期末期产生的，但谷物产量通常反映了早期的发育事件。例如，产量可能受到形成可育穗的枝条数量和/或与叶片数量相关的光合能量的影响。为了满足快速增长的谷物需求，育种者需要对调节植物结构的基因有复杂的分子了解，以便快速、自信地选择性能更好的作物，但对小麦和大麦这两种全球主要作物的温带谷物基因功能的了解尤其薄弱，反映出这些物种传统上对分子研究的抵制。然而，最近加速产生的复杂的大麦基因组和分子工具和资源有望通过使用这种作物作为发育模型来解锁温带谷物结构的发育遗传学。我提出的研究将利用其他植物模型系统中令人兴奋的工作，这些工作强调了保守的发育阶段网络在多种产量相关结构性状调节中的作用。该网络是由两个 microRNA (miRNA) 基因家族 miR156 和 miR172 之间的拮抗作用驱动的，这两个基因家族编码短的调节性 RNA 分子：miR156 在生命周期的早期丰富，可促进幼年特征，如叶子的产生，然而，随着时间的推移，miR156 水平下降，受到 miR172 水平上升的抑制，与成虫和繁殖性状相关。这些 miRNA 通过抑制多个目标转录因子发挥作用，这些转录因子本身调节基因以控制特定的发育特征。我的研究目标是了解温带谷物（特别是大麦）中哪些性状是由单个 miR156/172 调节的转录因子控制的，以及这些因素如何控制基因表达，以便为未来的育种工作提供信息。事实上，我已经发现大麦中编码 miR172 调节的转录因子的基因是茎和穗节间伸长的主要调节因子，从而直接影响谷物密度和植物高度，都是重要的农艺性状。高度会影响头重脚轻、谷物较多的作物的倒伏（倒伏），因此需要控制株高。该基因是第一个与大麦节间生长有关的转录因子，我预测它通过控制一系列下游基因的表达来发挥作用，这些基因也可能是潜在的育种目标。在这个项目中，我将采用基因表达、生化和测序技术来明确识别这些目标基因。此外，我将研究与节间生长涉及的其他途径可能的相互作用，作为构建解释节间生长的调控基因网络的第一步。此外，我将确定大麦中其他 miR156/172 调节的转录因子在何时何地表达。最后，我将使用强大的转基因方法来梳理个体对这些转录因子控制的其他性状的贡献。我预计通过这项研究，将识别和表征涉及农民重要性状的新基因，为作物育种提供信息。