Collaborative Research: The genetic basis, biosynthetic pathways and evolution of chemical defense in carabid beetles

合作研究：步甲的遗传基础、生物合成途径和化学防御进化

• 批准号: 1556931
• 负责人: Tanya Renner
• 金额: $ 28.42万
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1556931&HistoricalAwards=false
• 关键词: Collaborative; Research; genetic; basis; biosynthetic

The main goal of this project is to understand, at the molecular level, one of the most remarkable chemical defense systems found in nature - the explosive, extremely hot spray of the bombardier beetles. Insects make up much of the animal life that has evolved on Earth. Understanding why there are so many different kinds of insects and why they are so successful is fundamental to understanding how the wide diversity of life evolved. Insects are well known for producing many different chemical compounds that are required for their communication. Some chemicals help them to locate mates and food resources, others help them to organize activities within the nest or hive, and many others are used to warn off and defend against predators. This project focuses on this last aspect and is specifically testing the idea that the genes responsible for production of the hot chemical spray of the bombardier beetles are closely related to the genes responsible for producing similar chemicals in the insect's outer shell or exoskeleton. A main strength of the project is that it tackles this question by using multiple complementary approaches and by comparing eight different beetle species that are related to varying degrees. Half of these species have evolved a chemical defense system, the other half have not evolved this ability. Many college students and young scientists will receive scientific training in conjunction with the project. People of all ages are highly captivated by these beetles, particularly school age children. With the bombardier beetle as a model, the project will help develop elementary school level hands-on activities and lesson plans on topics in chemical ecology and biological chemical defense evolution that will reinforce the Next Generation Science.Ground beetles and their relatives form the largest clade of organisms that use a single homologous gland system to produce no less than 19 distinct classes of chemical compounds for defense. This project will develop a detailed functional and evolutionary understanding of defensive chemistry evolution by focusing on species from the four lineages of quinone producing carabid beetles, including species commonly known as the bombardier beetles, which chemically blast their defensive quinones at extremely hot temperatures (up to 100 °C). Using a multidisciplinary approach, this project will identify genes involved in quinone production, elucidate chemical biosynthetic pathways, and describe the genetic architecture of quinone evolution. From gland-specific transcripts, candidate genes related to the production of defensive secretions will be identified and gene function will be validated experimentally by blocking gene transcription and looking at phenotypic changes in the compounds produced. The researchers will test the hypothesis that the genes up-regulated in secretory cells during quinone synthesis are closely related to those involved in quinone production in arthropod cuticle. Thus the project will empirically address the well-known, but untested, scenario of how the bombardier beetle evolved its explosive defense abilities. Ultimately, this project will explore how genetics and chemistry can interact over time and will reveal insights into the fundamental process of evolution.

这个项目的主要目标是在分子水平上了解自然界中发现的最显著的化学防御系统之一--轰炸机甲虫的爆炸性、极热的喷雾。昆虫构成了地球上进化的动物的大部分。了解为什么有这么多不同种类的昆虫，为什么它们如此成功，这是理解生物多样性是如何进化的基础。众所周知，昆虫会产生许多不同的化合物，这是它们交流所必需的。一些化学物质帮助它们寻找配偶和食物来源，另一些帮助它们在巢或蜂巢内组织活动，还有许多其他化学物质被用来警告和防御捕食者。这个项目专注于最后一个方面，并专门测试了这样一种想法，即负责产生轰炸机甲虫热化学喷雾的基因与负责在昆虫外壳或外骨骼中产生类似化学物质的基因密切相关。该项目的一个主要优点是，它通过使用多种互补的方法并通过比较八种不同的甲虫物种来解决这个问题，这些甲虫物种的相关程度不同。这些物种中有一半进化出了化学防御系统，另一半则没有进化出这种能力。许多大学生和青年科学家将接受与该项目相关的科学培训。所有年龄段的人都非常着迷于这些甲虫，特别是学龄儿童。以庞巴迪甲虫为模型，该项目将帮助开发小学水平的动手活动和课程计划，主题为化学生态学和生物化学防御进化，这将加强下一代科学。甲虫及其近亲构成最大的有机体分支，使用单一同源腺体系统产生至少19种不同类别的防御性化合物。该项目将对防御性化学进化形成详细的功能和进化方面的了解，重点关注四种产苯二酚的步甲物种，包括通常被称为轰炸机甲虫的物种，这些物种在极热的温度(高达100摄氏度)下对其防御性化学进化进行化学爆炸。该项目将使用多学科方法，识别与苯二酚生产有关的基因，阐明化学生物合成途径，并描述苯二酚进化的遗传结构。从腺体特异的转录本中，将识别与产生防御性分泌物相关的候选基因，并将通过阻止基因转录和观察产生的化合物的表型变化来实验验证基因功能。研究人员将验证这一假设，即在苯醌合成过程中分泌细胞中上调的基因与节肢动物角质层中参与苯醌生产的基因密切相关。因此，该项目将从经验上解决轰炸机甲虫如何进化其爆炸性防御能力的众所周知但未经测试的情景。最终，这个项目将探索遗传学和化学如何随着时间的推移相互作用，并将揭示对进化的基本过程的洞察。