Collaborative Research: Macroevolution of a group of plant secondary defense compounds (pyrrolizidine alkaloids) in the dogbane and milkweed flowering plant family (Apocynaceae)

合作研究：罗布麻和马利筋开花植物家族（夹竹桃科）中一组植物二级防御化合物（吡咯里西啶生物碱）的宏观进化

• 批准号: 1655660
• 负责人: Kevin Minbiole
• 金额: $ 15.69万
• 依托单位: Villanova University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1655660&HistoricalAwards=false
• 关键词: Collaborative; Research; Macroevolution; group; plant

Plants are known to synthesize about 200,000 distinct secondary metabolites, chemical compounds that are not essential for their cellular metabolism. These plant secondary chemicals are important sources of medicines (e.g. aspirin), pesticides (e.g. pyrethrin), industrial compounds (e.g. latex), flavors (e.g. mint), and poisons (e.g. strychnine). To plants, these chemicals are essential defenses against herbivores, particularly insects. The efficacy of these defenses is not static over time, however, as herbivores adapt to their host plants defenses, evolving mechanisms to detoxify them or even co-opt them for their own defense against their predators. Thus a chemical that was once a valuable defense may become a liability, and its production lost. This project will investigate the evolution of a group of plant defense secondary compounds (pyrrolizidine alkaloids) in the dogbane and milkweed family (Apocynaceae). Plant secondary compounds in the Apocynaceae are diverse, with many having medicinal properties. Pyrrolizidine alkaloids in members of the Apocynaceae are highly toxic to non-adapted herbivores, but have little effect on specialist insects that store them within their tissues for defense against predators. Researchers will sample broadly across the Apocynaceae and reconstruct evolutionary relationships within the family using DNA sequence data. The resulting evolutionary tree will then be used as a framework to reconstruct the evolution of pyrrolizidine alkaloids within the group and better understand the relationship between these chemicals, the plants that produce them, and their herbivores. Undergraduate students will be trained in diverse molecular, evolutionary and biochemistry methods. Results from this project will also be integrated into undergraduate classes at three institutions, including two primarily undergraduate institutions. The research will provide new insights into evolutionary relationships within the medically important Apocynaceae plant family that can be used as a framework for broader questions within the family. An exhibit at the Academy of Natural Sciences in Philadelphia will broadly disseminate results from this research, and information on the broader topics of plant and insect defense, chemistry, and co-evolution, to the public. The overarching hypothesis to be tested in this research project proposes that the diversity of pyrrolizidine alkaloids will be lower in plant lineages that are highly exploited by insects immune to the effects of these compounds. To test this hypothesis researchers will use a combination of targeted enrichment and genome skimming (Hyb-Seq) to sequence ca. 850 low-copy nuclear loci, whole chloroplast genomes, and nuclear ribosomal genes, from 2 species of each of the 287 genera of the APSA clade (the lineage within Apocynaceae that includes most known milkweed butterfly host plants) to generate the required well-resolved and supported phylogeny and chronogram of the family. Researchers will then conduct a systematic survey of pyrrolizidine alkaloids occurrence in leaves across the APSA clade and reconstruct the evolution of both the pyrrolizidine alkaloids phenotype and of the underlying biosynthetic pathway, as well as expression and functional analyses in a subset of species. The origin of pyrrolizidine alkaloid biosynthesis in Apocynaceae will then be compared to the age of pyrrolizidine alkaloid co-option by Danainae, and test if the loss of pyrrolizidine alkaloids is correlated with host plant status.

已知植物可以合成约200,000个不同的二级代谢物，这些化合物对于其细胞代谢而言并不重要。这些植物二次化学物质是重要的药物来源（例如阿司匹林），农药（例如丙烯酸酯），工业化合物（例如乳胶），口味（例如薄荷）和毒药（例如，斯特rychnine）。对于植物而言，这些化学物质是针对草食动物，尤其是昆虫的必不可少的防御能力。这些防御能力随着时间的流逝并不是静态的，因为食草动物适应了宿主植物的防御能力，不断发展的机制来对其进行排毒，甚至可以为他们自己的防御，以防止他们对捕食者进行防御。因此，曾经是有价值的防御的化学物质可能会成为一种责任，其产量损失了。该项目将研究Dogbane和Milkweed家族（Apocynaceae）中一组植物防御二次化合物（吡咯烷生物碱）的演变。植物科中的植物次要化合物多种多样，许多化合物具有药用特性。载旋菌科成员中的吡咯烷生物碱对非适应的草食动物有剧毒，但对将其存放在组织中的专业昆虫几乎没有影响，无法防御捕食者。研究人员将使用DNA序列数据在家庭中广泛取样，并在家庭中重建进化关系。然后，所产生的进化树将被用作框架，以重建组内吡咯烷生物碱的进化，并更好地理解这些化学物质，产生它们的植物及其草食动物之间的关系。本科生将接受各种分子，进化和生物化学方法的培训。该项目的结果还将集成到三个机构的本科课程中，包括两个主要是本科机构。这项研究将为医学上重要的载体植物家族中的进化关系提供新的见解，该家族可以用作家庭内部更广泛问题的框架。费城自然科学院的展览将广泛传播这项研究的结果，并向公众提供有关植物和昆虫防御，化学和共同进化的广泛主题的信息。在本研究项目中要检验的总体假设表明，在植物谱系中，吡咯烷生物碱的多样性将较低，这些植物谱系被昆虫高度利用，免疫这些化合物的作用。为了检验这一假设，研究人员将使用靶向富集和基因组掠夺（HYB-SEQ）的组合来序列。 850个低拷贝的核基因座，全叶绿体基因组和核核糖体基因，来自APSA进化枝的287属的2种（APSA属中的287种）（载孢子科中的谱系，包括最著名的Milkweed蝴蝶宿主植物），以产生所需的良好分辨和支撑的良好的养生和支撑的生物和基础。然后，研究人员将对APSA进化枝的叶子中发生吡咯烷碱性生物碱的系统进行系统调查，并重建吡咯烷定生物碱表型的演化以及基本的生物合成途径，以及物种子集中的表达和功能分析。然后将将吡咯烷碱性生物碱生物合成的起源与danainae相比，将与吡咯烷生物碱生物碱的年龄进行比较，并测试是否丧失了吡咯烷碱性生物碱生物碱的丧失与宿主植物的状态相关。

项目成果

Chemotaxonomic investigation of Apocynaceae for retronecine-type pyrrolizidine alkaloids using HPLC-MS/MS

• DOI: 10.1016/j.phytochem.2021.112662
• 发表时间: 2021-03-27
• 期刊: PHYTOCHEMISTRY
• 影响因子: 3.8
• 作者: Barny, Lea A.;Tasca, Julia A.;Minbiole, Kevin P. C.
• 通讯作者: Minbiole, Kevin P. C.