Understanding the genetic mechanisms of phenotypic plasticity in insect migration

了解昆虫迁徙表型可塑性的遗传机制

• 批准号: BB/N012011/1
• 负责人: Christopher Jones
• 金额: $ 37.73万
• 依托单位: Rothamsted Research
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FN012011%2F1
• 关键词: Understanding; genetic; mechanisms; phenotypic; plasticity

Each year billions of insects migrate thousands of kilometres in search of food, shelter and places to breed. Embarking on such an arduous journey requires physiological, behavioural and morphological adaptations encoded by multiple genes. For many insects, migration is 'switched on' in anticipation of deteriorating habitats, allowing populations to succeed in the face of environmental stress. This ability to respond to environmental cues in a single generation requires a flexible genetic basis that triggers migratory behaviour and is highly likely to be due to changes in gene expression (the process of using genetic information to produce functional proteins) based on similar behavioural plasticity in other insects. The specific genes and biochemical processes which contribute to this phenomenon are poorly understood. This project will address this knowledge gap by studying the genetic basis of migration in response to environmental cues using the global insect pest, Helicoverpa armigera. H. armigera is a noctuid moth present throughout much of Asia, Africa, the Middle East and Europe and is capable of infesting over one hundred host plants including many crops, with the caterpillar stage causing damage through direct feeding. It is the ability of H. armigera to migrate thousands of kilometres between host crops that make it such a major pest. Characterising migration in the laboratory in any organism is not easy. However, by using a computerised tethered flight system, designed and built at Rothamsted Research, it is possible to fly up to 32 moths per night and electronically record the distance, time and speed of each individual flight. This permits an accurate assessment of flight performance which can be used as a proxy for migratory versus sedentary behaviour. The flight propensity of H. armigera collected directly from host plants in China and Greece has previously been characterised. Using a technology called RNA-seq (a high-throughput sequencing tool which determines both the full sequence and the number of RNA molecules present in each sample), over 200 genes have been identified that are differentially expressed between migratory and sedentary flight phenotypes. Many of these genes have potential roles in processes associated with migration biology including flight muscle, the metabolism and hormonal stimulation. It is not known, however, which genes drive facultative migratory behaviour or how their expression is affected by environmental stimuli. The initial objective of this proposal will be to expose larvae of H. armigera to one of three environmental cues (density, photoperiod and nutrition) that are important migratory triggers in noctuid moths. The adults from each of these experiments will be flown on the flight mills to determine the impact of each cue on flight ability. The expression of 50 of the most promising candidate genes will be quantified - from the 200 genes identified using RNA-seq - in individual moths to determine those genes that show the strongest association with flight in response to each cue. RNA interference (the delivery of double-stranded RNA into a cell to inhibit gene expression) will be used to silence the five genes that explain the greatest proportion in flight propensity according to their expression patterns and examine their role in migration on the flight mills. Finally, the same five genes will be expressed in a second organism, the fruitfly (Drosophila melanogaster), to see whether they induce increased flight performance on a modified set of flight mills designed for smaller insects. The combination of these techniques will contribute greatly to our understanding of the genetic basis of migration in H. armigera, and in particular, migration in response to environmental cues. The results will be applicable to other important migratory moths and will set the benchmark for this area of research for the foreseeable future.

每年有数十亿的昆虫迁徙数千公里，寻找食物、庇护所和繁殖地。踏上这样一段艰难的旅程需要由多个基因编码的生理、行为和形态适应。对于许多昆虫来说，迁移是在预期栖息地恶化的情况下“开启”的，使种群能够在环境压力面前取得成功。这种在一代人中对环境线索做出反应的能力需要灵活的遗传基础，这种遗传基础触发了迁移行为，并且很可能是由于基因表达的变化（使用遗传信息产生功能蛋白质的过程）基于其他昆虫类似的行为可塑性。导致这种现象的特定基因和生化过程知之甚少。该项目将利用全球性害虫棉铃虫，研究环境线索引起的迁移的遗传基础，从而填补这一知识空白。H.棉铃虫是一种存在于亚洲、非洲、中东和欧洲大部分地区的粘虫蛾，能够侵染超过100种宿主植物，包括许多农作物，其中毛虫阶段通过直接取食造成损害。这是H的能力。棉铃虫在寄主作物之间迁移数千公里，使其成为如此主要的害虫。在实验室中描述任何生物体的迁移特征并不容易。然而，通过使用由Rothamsted Research设计和建造的计算机化系留飞行系统，每晚可以飞行多达32只飞蛾，并以电子方式记录每次飞行的距离，时间和速度。这使得能够准确评估飞行性能，可用作迁移与久坐行为的代表。H.直接从中国和希腊的寄主植物中收集的棉铃虫先前已被表征。使用一种称为RNA-seq的技术（一种高通量测序工具，可以确定每个样本中存在的RNA分子的完整序列和数量），已经确定了200多个基因在迁移和久坐飞行表型之间的差异表达。这些基因中的许多在与迁移生物学相关的过程中具有潜在的作用，包括飞行肌肉、代谢和激素刺激。然而，目前还不知道哪些基因驱动兼性迁移行为，或者它们的表达如何受到环境刺激的影响。本建议的初步目标是暴露H.在棉铃虫中，密度、光周期和营养是重要的迁移触发因素之一。这些实验中的每一个成年人将在飞行米尔斯上飞行，以确定每个线索对飞行能力的影响。50个最有希望的候选基因的表达将被量化-从使用RNA-seq识别的200个基因中-在个体蛾中，以确定那些在响应每个线索时显示出与飞行最强关联的基因。RNA干扰（将双链RNA递送到细胞中以抑制基因表达）将用于沉默根据其表达模式解释飞行倾向中最大比例的五个基因，并检查它们在飞行米尔斯迁移中的作用。最后，同样的五个基因将在第二种生物--果蝇（Drosophila melanogaster）中表达，以观察它们是否会在为较小昆虫设计的一组改良的飞行米尔斯上诱导增加飞行性能。这些技术的结合将极大地有助于我们理解H.特别是对环境因素的反应。研究结果将适用于其他重要的迁徙蛾类，并将在可预见的未来为这一研究领域设定基准。

项目成果

Genome-Wide Characterization of DNA Methylation in an Invasive Lepidopteran Pest, the Cotton Bollworm Helicoverpa armigera.

• DOI: 10.1534/g3.117.1112
• 发表时间: 2018-03-02
• 期刊: G3 (Bethesda, Md.)
• 作者: Jones CM;Lim KS;Chapman JW;Bass C
• 通讯作者: Bass C

Microsatellites reveal that genetic mixing commonly occurs between invasive fall armyworm populations in Africa.

• DOI: 10.1038/s41598-021-00298-3
• 发表时间: 2021-10-21
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Withers AJ;de Boer J;Chipabika G;Zhang L;Smith JA;Jones CM;Wilson K
• 通讯作者: Wilson K

The tethered flight technique as a tool for studying life-history strategies associated with migration in insects.

• DOI: 10.1111/een.12521
• 发表时间: 2018-08
• 期刊: Ecological entomology
• 影响因子: 2.2
• 作者: Minter M;Pearson A;Lim KS;Wilson K;Chapman JW;Jones CM
• 通讯作者: Jones CM