Genetic basis of salt tolerance in Anopheles gambiae s.l.

描述（由申请人提供）：每年约有80万人死于疟疾。虽然目前可用的病媒控制工具（主要是蚊帐和室内杀虫剂喷洒）大大减少了疟疾病例和死亡，但由于耐药性的威胁，这一公共卫生成就是脆弱的。此外，即使没有耐药性，现有工具也不足以在疟疾高传播和稳定的地方阻断疟疾传播，例如在非洲许多地区。开发新的针对媒介的工具是必要的，但这取决于目前缺乏的对蚊子生态和行为的理解。在这里，我们研究了许多重要的疟疾媒介中发现的耐盐水特性，这种特性在决定蚊子的栖息地利用和生态分布中起着关键作用，从而在疟疾传播中起着重要作用。我们的目标是剖析非洲疟疾病媒An耐盐水的遗传基础。它是主向量An的近亲。冈比亚按蚊。我们将剖析安的耐盐水性。菜单通过两个互补的具体目的：绘制了安树耐盐性相关qtl的遗传图谱。使用多个菌落的An。菜单和安。冈比亚，我们已经证明了。菜单可以和An区别开来。冈比亚虫和它们的F1杂交后代在50%的海水中存活。我们将采用一种新的基于illumina的基因分型方法，在暴露于50%海水环境中存活/不能存活的回交后代中绘制重组断点，以定位控制耐盐性的QTL区域。2. 在淡水和咸水中鉴定与发育相关的差异基因表达。在50%的海水中存活取决于暴露的发育时间，并且在淡水和咸水饲养的幼虫中，直肠中离子转运蛋白（Na/K atp酶）的定位是不同的。我们假设这些观察结果是由于暴露于盐水引发的差异表达。我们将验证这一假设，并通过比较淡水和咸水饲养的幼虫之间的整体基因表达来确定候选基因。在这个为期两年的项目结束时，来自QTL定位和差异基因表达的综合证据将引导我们找到有助于疟疾病媒An耐盐性的候选基因和/或候选基因区域。长节。与其他可能是多基因的、具有流行病学重要性的复杂生态、行为和生活史特征不同，耐盐性相对容易处理，可能由几个影响较大的主要基因控制，并且易于测定。利用下一代基因组工具剖析这种适应性性状的遗传基础，为未来了解这些媒介蚊子适应异质和不断变化的环境的机制奠定了基础，开辟了媒介控制的新途径。

DESCRIPTION (provided by applicant): About 800,000 people die each year from malaria. While the currently available vector control tools-mainly bed nets and indoor insecticide spraying-are substantially reducing malaria cases and deaths, this public health success is fragile due to the threat of resistance. Moreover, even without resistance, existing tools are insufficient to interrupt malaria transmission where it is high and stable, as in many parts of Africa. The development of new vector-targeted tools is imperative, but depends on an understanding of mosquito ecology and behavior that is currently lacking. Here we study saltwater tolerance, a trait found in numerous important malaria vectors that plays a key role in determining habitat use and ecological distribution of mosquitoes, and thus their contribution to malaria transmission. Our objective is to dissect the genetic basis of saltwater tolerance in the African malaria vector An. merus, a close relative of the primary vector An. gambiae. We will dissect saltwater tolerance in An. merus through two complementary specific aims: 1. Genetically map QTLs that contribute to salinity tolerance in An. merus Using multiple colonies of An. merus and An. gambiae, we have shown that An. merus can be distinguished from An. gambiae and their F1 hybrids by survival in 50% seawater. We will apply a novel Illumina-based genotyping approach to map recombination breakpoints in individual backcross progeny that do/do not survive exposure to 50% seawater, to localize QTL regions that control salinity tolerance. 2. Identify differential gene expression associated with development in fresh vs. saltwater We have shown that the ability of An. merus to survive in 50% seawater is dependent upon developmental timing of exposure, and that the localization of an ion transporting protein (Na/K ATPase) in the rectum differs in fresh vs. saltwater-reared larvae. We hypothesize that these observations are due to differential expression triggered by exposure to saltwater. We will test this hypothesis and identify candidate genes by comparing global gene expression between fresh vs. saltwater-reared larvae. At the end of the two-year project, combined evidence from QTL mapping and differential gene expression will lead us to candidate genes and/or candidate gene regions that contribute to salinity tolerance in the malaria vector An. merus. Unlike other complex ecological, behavioral and life history traits of epidemiological importance that are probably polygenic, saltwater tolerance is relatively tractable, likely governed by a few major loc with large effects, and simple to assay. The ability to dissect the genetic basis of this adaptive trait using next generation genomic tools lays the groundwork for future efforts to understand the mechanisms by which these vector mosquitoes adapt to a heterogeneous and changing environment, opening up new avenues of vector control. PUBLIC HEALTH RELEVANCE: Currently available tools to combat malaria are insufficient to interrupt disease transmission where it is high and stable, as in many parts of Africa. The development of new vector-targeted tools is imperative, but depends on an understanding of mosquito ecology and behavior that is currently lacking. Here we study saltwater tolerance, a trait found in numerous important malaria vectors that plays a key role in determining habitat use and ecological distribution, and hence malaria transmission in coastal regions.