BBSRC-NSF/BIO: Anatomy and functions of LTP interactomes and their relationship to small RNA signals in systemic acquired resistance

植物具有一种独特的免疫形式，称为系统获得性抗性(SAR)。合成孔径雷达是非常可取的，因为它保护整个植物免受各种病原体的侵袭，而且是持久的。当主要病原体感染植物并激活SAR时，感染部位产生的移动信号传播到植物的远端，并为抵御未来的感染做好准备。已经发现了几个导致合成孔径雷达的因素，包括一些系统性运动的因素，尽管早期合成孔径雷达信号的身份仍然难以捉摸。在最近的一项突破中，我们发现了基于RNA的分子，它们在SAR的早期时间框架内发挥作用。肯塔基大学和华威大学的实验室之间的这个合作项目将结合计算、生化、基因组和新陈代谢分析，以产生对这些分子的深入机械理解。通过促进利用SAR制定可持续和环保的作物保护策略，以及它对经济上重要的作物物种的适用性，这一项目将使美国和英国的农业经济受益。所获得的知识可能在人类健康中有合理的应用，因为潜在的成分在哺乳动物生理学中具有保守的功能。该项目将为主要来自服务不足背景的肯塔基州学生产生本科研究经验，通过肯塔基州青年科学峰会、初中研讨会、女童子军宝石计划、山上科学公共参与系列和基于研究的本科生体验式学习课程。本项目将研究系统性获得性抗性(SAR)的早期信号。SAR移动信号的产生被认为发生在初次侵染后的3h内，感染叶片必须在接种后至少4h保持附着，才能诱导SAR，这表明移动信号在早期时间段内被转移。我们发现，来自反式作用小干扰RNA3a(TAS3a)的两个21核苷酸RNA(TASI-RNA)在病原菌感染后3h内合成，并在4h内移动到远端叶片，在SAR中起到难以捉摸的早期移动信号的作用。TAS3a裂解生长素反应因子(ARF)3，反之，增加ARF3负调控SAR。TAS3a正向调节脂转移蛋白(LTP)3、4和AZI1以及一种新的蛋白A70的表达。LTPS通过促进TASI-ARF的运输形成一个复杂的、调节的SAR。LTPS的系统流动性进一步表明，SAR的激活与高分子量LTP-RNA复合体的运输有关。该项目将表征LTP-RNA相互作用组和A70系统激活的动力学，并将计算这些复合体的变化如何调节SAR。此外，我们还将描述在TASI-ARF和A70下游发挥作用的ARF3靶标和与SAR相关的成分。研究成果将通过传统的出版途径、在会议上的陈述、通过年度会议和以种植者为目标的出版物向美国大豆、玉米、小麦和燕麦种植者进行推广，以及向英国的蔬菜和受保护作物种植者和种子公司传播。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plants possess a unique form of immunity called systemic acquired resistance (SAR). SAR is highly desirable because it protects the whole plant against a wide range of pathogens and is long-lasting. When a primary pathogen infects the plant and activates SAR, mobile signals generated at the infection site travel to distal portions of the plant and prepare them to fend off future infections. Several SAR-inducing factors, including some that move systemically, have been discovered, though the identity of the early SAR signal has remained elusive. In a recent breakthrough, we identified RNA-based molecules that function within the early time frame of SAR. This collaborative project between laboratories at the University of Kentucky and University of Warwick will combine computational, biochemical, gentics and metabolomic analyses to generate a deep mechanistic understanding of these molecules. By facilitating the use of SAR in developing sustainable and environmentally friendly crop protection strategies, and its applicability to economically important crop species, this project will benefit US and UK agricultural economies. The knowledge gained could have rational applications in human health because the underlying components have conserved functions in mammalian physiology. The project will generate undergraduate research experiences for Kentucky students from primarily underserved backgrounds, middle-high school workshops via the Kentucky Youth Science Summit, Girl Scout’s GEMS program, Science on the Hill public engagement series and undergraduate research-based experiential learning coursework. This project will investigate early signals in Systemic Acquired Resistance (SAR). The production of the SAR mobile signal is thought to occur within 3 h of primary infection, and the infected leaf must remain attached for at least 4 h after inoculation for SAR to be induced, suggesting that the mobile signal is translocated during that early timeframe. We find that two phased 21 nucleotide RNA (tasi-RNA) derived from Trans-Acting Small Interfering RNA3a (TAS3a), are synthesized within 3 h of pathogen infection, move to distal leaves within 4 h and function as the elusive early mobile signal in SAR. TAS3a cleaves Auxin Response Factor (ARF) 3 and conversely increased ARF3 negatively regulates SAR. TAS3a positively regulates the expression of Lipid Transfer Proteins (LTP) 3, 4 and AZI1 and a novel protein A70. The LTPs form a complex and regulate SAR by promoting transport of tasi-ARFs. Systemic mobility of the LTPs further suggests that SAR activation is associated with the transport of a high molecular weight LTP-RNA complex. This project will characterize the LTP-RNA interactome and the dynamics of systemic activation of A70, and will compute how changes in these complexes regulate SAR. In addition, we will characterize ARF3 targets and SAR-associated components that function downstream of tasi-ARFs and A70. Research findings will be disseminated to the scientific community via traditional publication routes, presentations at conferences, and through outreach to US soybean, corn, wheat, and oat growers via annual meetings and grower-targeted publications, as well as with vegetable and protected crop growers and seed companies in the UK.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.