RoL: Control of trans-species microRNA expression

寄生植物可能是有害的杂草，会攻击农作物并影响农业生产力。寄生植物Qodder(葫芦属)在美国广泛存在，对各种作物都是一个问题。控制驼鹿的策略是有限的。茯丝子影响寄主的一种方式是向寄主茎中注入短片段的遗传信息，即“microRNAs”。这些“跨物种”的microRNA会破坏某些目标宿主基因。这一过程似乎允许寄生虫抑制宿主的免疫系统。这个项目试图准确地了解Dodder跨物种microRNAs是如何被激活并注入宿主植物的。了解这一过程可能导致新的控制方法，从而使农业受益。其他寄生虫和病原体使用跨物种的microRNA来操纵它们的宿主。因此，从Dodder跨物种microRNAs的研究中获得的细节可能有助于对更广泛的寄生虫和病原体的研究。最近的研究表明，Dodder(葫芦门)表达许多进入寄主植物组织和靶向寄主mRNAs的microRNAs。这些跨物种的microRNAs可能作为毒力因子关闭宿主mRNAs，以便使寄生虫受益。与典型的microRNAs不同，Cuscuta跨物种microRNAs只聚集在宿主和寄生虫之间的界面上。Cuscuta基因组中跨物种microRNA基因座上游的核心启动子都有一个共同的上游序列元件(USE)，这是典型的microRNAs所没有的，也是Cuscuta mRNAs的启动子所没有的。10个碱基对的使用序列与已知在所有植物中驱动小核RNA(SnRNAs)转录的使用元件相同。因此，Cuscuta跨物种microRNAs似乎已经选择了一个预先存在的、构成启动子的元件来驱动高度组织特异性的表达模式。该项目将试图通过两个目标来了解这一过程：目标1：用途的功能分析，以确定其在葫芦巴跨物种microRNA前体转录中的作用。目标2：使用约束因素的识别和功能分析(S)。该奖项反映了美国国家科学基金会的法定使命，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。

Parasitic plants can be noxious weeds that attack crops and affect agricultural productivity. The parasitic plant Dodder (genus Cuscuta) is widespread in the United States and is a problem on diverse crops. Strategies to control Dodders are limited. One way that Dodders affect their hosts is by injected short bits of genetic information, "microRNAs", into host stems. These "trans-species" microRNAs destroy certain target host genes. This process seems to allow the parasite to suppress the host's immune system. This project seeks to understand exactly how the Dodder trans-species microRNAs are activated and injected into the host plants. Understanding this process could lead to novel methods of control and thus would benefit agriculture. Other parasites and pathogens use trans-species microRNAs to manipulate their hosts. Thus, details learned from study of the Dodder trans-species microRNAs may inform research into a broader array of parasites and pathogens.Recent studies have shown that Dodder (Cuscuta) expresses many microRNAs which enter host plant tissues and target host mRNAs. These trans-species microRNAs are likely acting as virulence factors to shut down host mRNAs in order to benefit the parasite. Unlike canonical microRNAs, the Cuscuta trans-species microRNAs only accumulate at the interface between the host and parasite. The core promoters upstream of trans-species microRNA loci in the Cuscuta genome all have a common Upstream Sequence Element (USE) that is absent from canonical microRNAs and also absent from the promoters of Cuscuta mRNAs. The 10 base-pair USE sequence is identical to the USE element known to drive transcription of small nuclear RNAs (snRNAs) in all plants. It thus appears that Cuscuta trans-species microRNAs have co-opted a pre-existing, constitutive promoter element to drive a highly tissue-specific expression pattern. This project will seek to understand this process via two aims: Aim 1: Functional analyses of USE to determine its role in the transcription of Cuscuta trans-species microRNA precursors. Aim 2: Identification and functional analyses of the USE-binding factor(s).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.