Collaborative Research: EDGE CMT: Genomic and molecular bases of pollination syndrome evolution in monkeyflowers

复杂性状(如人类身高)的变异通常是由多个基因引起的。鉴定和表征这些多基因特征背后的致病基因和突变仍然是生物学中的一个中心挑战。植物中这种适应的最耐人寻味的例子之一是授粉综合症，这是一套花卉特征，使花与它们的动物传粉者(例如蜜蜂、蜂鸟、鹰蛾)之间有特殊的联系。例如，蜂鸟授粉的花通常体型大，颜色红色，产蜜丰富，生殖器官发达，而蜜蜂授粉的花通常颜色多样(但不是红色)，花蜜数量较少，生殖器官嵌入，着陆平台清晰。从一种授粉综合征到另一种授粉综合征的进化转换需要多个花性状的协调变化，每个性状都受多个基因控制，然而这些开关在自然界中在许多植物群中迅速发生。这项研究使用了一种新的遗传模型系统，猴花，来研究授粉综合征切换是如何在基因组和分子水平上发生的。此外，本研究通过传粉综合征的视角，将研究与学生教育和公共宣传相结合。具体活动包括在康涅狄格大学校园的一个公共花园进行有组织的传粉者观察实验，以提高公众对动物传粉服务的认识，在哈弗福德学院创建基于生物信息学课程的本科生研究体验，并制作专业视频，将传粉综合症的研究带入YouTube频道，科学IRL(在现实生活中)。该项目的总体目标是系统地剖析三种近缘猴花(Mimulus)物种花卉性状差异的基因组和分子基础，这三种物种表现出三种不同的传粉综合征，包括蜜蜂授粉的莱维希、蜂鸟授粉的红花、蜂鸟授粉的红花和自花授粉的帕里西米。通过稳定的转基因，这些物种可以接受精细的遗传图谱和严格的功能询问。我们计划通过追求以下具体目标来实现我们的总体目标：(I)建立高质量的近等基因系(NIL)，它与亲本物种只有一个从其他物种导入的单一花性状基因座不同，并利用这些近等基因系从遗传上剖析授粉综合征开关背后的每个数量性状基因座(QTL)；(Ii)利用稳定的转基因实验从功能上表征单个QTL下的因果基因和突变；(Iii)利用加权基因共表达网络分析构建控制授粉综合征组成部分性状的基因调控网络/模块。这项研究的结果有望提供对授粉综合征开关的原因基因的深入的、全基因组的看法，确定一组控制个体花卉性状的基因调控模块，这些模块应该在其他植物系统中广泛应用，并揭示新的分子机制，不仅可以为植物，也可以为其他生物的表型进化研究提供信息。这一奖项反映了NSF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。

Variation in complex traits (e.g., human height) is usually caused by multiple genes. Identification and characterization of the causal genes and mutations underlying these multi-gene traits remain a central challenge in biology. One of the most intriguing examples of such adaptations in plants is the pollination syndrome, a suite of floral traits that enable specialized associations between flowers and their animal pollinators (e.g., bees, hummingbirds, hawkmoths). For example, hummingbird-pollinated flowers are usually large in size, red in color, with copious nectar production and exerted reproductive organs, whereas bee-pollinated flowers usually display various colors (but not red), a smaller quantity of nectar, inserted reproductive organs, and a clear landing platform. Evolutionary transitions from one pollination syndrome to another require coordinated changes of multiple floral traits, with each trait controlled by multiple genes, yet these switches occur rapidly in nature in many plant groups. This study employs a new genetic model system, monkeyflowers, to investigate how pollination syndrome switches occur at the genomic and molecular level. Furthermore, this study integrates research with student education and public outreach through the lens of pollination syndromes. Specific activities include organized pollinator observation experiments in a common garden on the University of Connecticut campus to raise public awareness of animal pollination service, creation of a bioinformatic Course-based Undergraduate Research Experience at Haverford College, and production of professional videos that bring pollination syndrome research to life to be released on a highly subscribed YouTube channel, Science IRL (‘in real life’).The overall objective of this project is to systematically dissect the genomic and molecular bases of floral trait variation among three closely related monkeyflower (Mimulus) species that display three distinct pollination syndromes, including the bee-pollinated M. lewisii, the hummingbird-pollinated M. cardinalis, and the self-pollinated M. parishii. These species are amenable to fine-scale genetic mapping and rigorous functional interrogation through stable transgenics. We plan to accomplish our overall objective by pursuing the following specific aims: (i) Generate high-quality near-isogenic lines (NILs), which differ from a parental species by only a single floral trait locus introgressed from another species, and use the NILs to genetically dissect each quantitative trait locus (QTL) underlying the pollination syndrome switches, (ii) Functionally characterize the causal genes and mutations under individual QTLs using stable transgenic experiments, (iii) Construct gene regulatory networks/modules that control pollination syndrome component traits using weighted gene co-expression network analysis. Results from this study are anticipated to provide an in-depth, genome-wide view of the causal genes underlying pollination syndrome switches, to identify a set of gene regulatory modules controlling individual floral traits that should be widely applicable in other plant systems, and to reveal novel molecular mechanisms that can inform studies of phenotypic evolution in not only plants, but also other organisms.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.