Bilateral BBSRC-FAPESP. The collision of two genomes: The invasion genomics of Helicoverpa crop pests in Brazil

双边 BBSRC-FAPESP。

• 批准号: BB/V001329/1
• 负责人: Chris Jiggins
• 金额: $ 69.25万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FV001329%2F1
• 关键词: Bilateral; BBSRC; FAPESP.; collision; two; Bilateral; BBSRC; FAPESP.; collision; two

Invasive crop pests are a major challenge of our times, and lead to huge economic costs to agriculture. One less well recognised aspect of such invasions is that invasive species often hybridise with related native species. This can have various potential outcomes: One possibility is that hybridisation leads to a collapse of the species barrier and a single mixed population. Alternatively, if the two species maintain their integrity they may nonetheless exchange genes, potentially allowing genes for adaptation to the novel range to facilitate the invasive species, and genes for pest-related traits to enter the native species. We will study these phenomena in the economically devastating crop pests Helicoverpa armigera, which has recently invaded and is hybridising with a native species Helicoverpa zea in Brazil. With Brazilian Project Partners we will conduct temporal and geographic monitoring of the invasion across a large scale, facilitated by large scale whole genome sequencing. We will use a novel sequencing approach to obtain genomic data for a large sample of populations of both species, which will allow us to address the following questions: What is the extent and speed of spread by the invasive species, what is the age of the hybridisation event and is there evidence for multiple sources of invaders, and finally what are the genetic consequences of hybridisation for the two species. In order to achieve these goals we will first generate high quality genome assemblies for both species, assembled to chromosomal level. This will provide resources that will be used by the community in the future for genetic manipulation and more broadly gaining a better understanding of these important crop pests.The two species have diverged in allopatry for over a million years, so genetic differences between them mean that we will have considerable power to identify blocks in the genomes of both species that have resulted from genetic mixing between the species (introgression). The size and distribution of these blocks provides information about the time since hybridisation. We will also determine whether there is evidence for incompatibilities between the two genomes that would help to maintain their distinctiveness in the face of mixing through hybridisation, by looking for genetic combinations that are under-represented in hybrids. In contrast regions that are more common than expected by chance would indicate adaptive introgression. This is likely for genes involved in adaptation to local conditions in Brazil that may move into the invasive species, or genes for insecticide resistance that are likely to move into the native species from the invader. Finally, we will search for signatures of recent adaptation in the populations of both species, which might be indicative of genomic regions involved in host adaptation, insecticide resistance or other traits of potential economic importance. In particular, Ha has developed resistance to a far wider range of insecticides and host species as compared to Hz, so there is potential for further introgression of alleles that could precipitate host range expansion and insecticide resistance in Hz. In contrast, Hz is adapted to local conditions in Brazil and might lend alleles that facilitate local adaptation to the invasive Ha populations.The project will uncover patterns that will be of immediate application in the control of this pest, for example forewarning of the arrival of the invader into new areas, and identifying characteristics such as insecticide resistance than could be transferred between the two species. In addition, we will address fundamental questions related to speciation biology, such as the nature of the genomic incompatibilities that keep species distinct.

侵入性农作物是我们时代的主要挑战，并带来了农业的巨大经济成本。这种入侵的一个不太认可的方面是，入侵物种通常与相关的本地物种混合。这可能具有各种潜在的结果：一种可能性是杂交导致物种障碍和单一混合种群的崩溃。另外，如果这两个物种保持其完整性，则可以交换基因，可能允许基因适应新范围以促进入侵物种，以及与虫害相关性状的基因进入本地物种。我们将研究这些现象在经济上毁灭性的作物害虫中Helicoverpa Armigera，该作物最近入侵并正在与巴西的本地物种Helicoverpa Zea杂交。与巴西项目合作伙伴一起，我们将对大规模的入侵进行时间和地理监测，这是由大规模的整个基因组测序促进的。我们将使用一种新型的测序方法来获取大量两种物种种群样本的基因组数据，这将使我们能够解决以下问题：侵入性物种的传播程度和速度是什么，杂交事件的时代是什么，并且有多种入侵者的证据，最后是多种物种的遗传后果。为了实现这些目标，我们将首先为这两个物种生成高质量的基因组组件，并组装到染色体水平。这将提供社区将来将用于遗传操作的资源，并更广泛地了解这些重要的作物害虫。这两个物种在同种异体中差异了一百万年，因此它们之间的遗传差异意味着我们将具有相当大的能力来识别这两种物种基因组中遗传混合的基因组中的障碍（内部混合）（内部结合的遗传混合）。这些块的大小和分布提供了有关杂交以来时间的信息。我们还将确定两个基因组之间是否有证据表明，通过寻找杂种中代表性不足的遗传组合，这两个基因组之间将有助于通过杂交混合而保持其独特性。与偶然预期更常见的对比区域将表明适应性渗入。这可能是针对适应巴西当地条件的基因，这些基因可能会进入入侵物种，或可能从入侵者进入本地物种的杀虫剂耐药性基因。最后，我们将搜索两种物种种群中最新适应的签名，这可能表明与宿主适应，抗杀虫剂抗性或其他潜在经济重要性有关的基因组区域。特别是，与Hz相比，HA已经对较宽范围的杀虫剂和宿主物种产生了抗性，因此有可能进一步渗入等位基因，这些等位基因可能会导致Hz中宿主范围扩张和杀虫剂的耐药性。相比之下，HZ适应了巴西的当地状况，可能会借用促进当地适应入侵性HA种群的等位基因。该项目将揭示在控制这种害虫中立即应用的模式，例如预见入侵者的到来，将入侵者的到来预见到新区域，并确定诸如杀虫剂的特征，例如在两个物种之间转移。此外，我们将解决与物种生物学有关的基本问题，例如使物种不同的基因组不相容性的性质。