EAGER: Dosage and Small RNA Regulation of Imprinting and Seed Development

智力优势：种子大小对作物驯化和自然种群中的适合度很重要，并且在很大程度上受到胚乳中母本和父本基因组平衡的影响，胚乳是大多数开花植物在受精时在种子内产生的组织。这种基因组平衡可能被破坏，导致对印记基因、以亲本特异性方式表达基因和种子大小的影响。在拟南芥中，增加父本基因组剂量可以导致较大的种子，而增加母本基因组剂量导致较小的种子，这表明母本和父本基因组的平衡影响胚乳和种子发育。在发育中的种子中，一类主要的短干扰RNA（siRNA）在母体中表达。在种子发育过程中胚乳发生全基因组去甲基化，表明小RNA作为负责亲本基因组平衡的因素，导致种子发育所必需的候选基因的表达变化。 母体siRNA可能调节对种子发育重要的蛋白质编码基因的表达。 在EAGER项目中，小分子RNA及其影响印记和种子的目标将被表征，小分子RNA的母体表达机制将被解决，并且将确定在胚乳发育过程中何时以及如何建立亲本的起源效应。更广泛的影响：种子生产对农业，粮食安全，可再生资源和人类营养至关重要。在机制水平上，这项研究的结果将揭示小RNA在调节基因表达和种子发育中的新生物学作用。新的小RNA靶标和候选基因将在该项目中被鉴定和表征，并且所选候选基因的功能将被严格测试。 更好地了解小RNA及其靶点如何调节种子发育，将最终帮助我们提高植物和动物的生产力和繁殖力。 植物种子、DNA序列、小RNA和基因表达数据将分别定期存入拟南芥生物资源中心（ABRC）、GenBank和基因表达综合数据库（GEO）。 在整个项目中，跨学科的培训机会，包括基因组学，表观遗传学，分子遗传学，植物生物学和计算生物学，将提供给研究生和本科生在这个项目。

Intellectual Merit: Seed size is important to crop domestication and fitness in natural populations and is largely affected by the balance of maternal and paternal genomes in endosperm, tissue produced inside the seeds of most flowering plants around the time of fertilization. This genome balance can be disrupted, resulting in effects on imprinted genes, expression of genes in a parent-of-origin specific manner, and seed size. In Arabidopsis thaliana, increased paternal genome dosage can result in larger seeds, whereas increased maternal genome dosage leads to smaller seeds, suggesting that the balance of maternal and paternal genomes affects endosperm and seed development. In the developing seed a major class of short-interfering RNAs (siRNAs), are maternally expressed. Genome-wide demethylation occurs in endosperm during seed development, suggesting that small RNAs serve as the factors responsible for the parental genome balance, leading to expression changes in candidate genes essential for seed development. It is likely that maternal siRNAs can regulate expression of protein-coding genes important to seed development. In this EAGER project, small RNAs and their targets that affect imprinting and seed will be characterized, the mechanism by which maternal expression of small RNAs is established will be addressed, and it will be determined when and how parent-of-origin effects are established during endosperm development.Broader Impact: Seed production is vital to agriculture, food security, renewable resources, and human nutrition. At the mechanistic level, results from this research will reveal a novel biological role for small RNAs in regulating gene expression and seed development. Novel small RNA targets and candidate genes will be identified and characterized in this project, and the functions of selected candidates will be rigorously tested. A better understanding of how small RNAs and their targets regulate seed development will ultimately help us improve productivity and fertility of plant and animals. Plant seeds, DNA sequences, and small RNA and gene expression data will be regularly deposited to Arabidopsis Biological Resource Center (ABRC), GenBank, and Gene Expression Omnibus (GEO), respectively. Throughout the project, interdisciplinary training opportunities, including genomics, epigenetics, molecular genetics, plant biology, and computational biology, will be provided for graduate and undergraduate students in this project.