Elucidating biosynthesis of the Lutzomyia longipalpis sandfly pheromone for sustainable production and control of leishmaniasis

利什曼病是由原生动物寄生虫引起的一组被忽视的热带疾病。在中美洲和南美洲，这种疾病是通过食血的沙蝇、长叶斑潜蝇和相关物种传播的。在利什曼病发病率最高的巴西，这种疾病是一个特别的挑战。控制长叶绿蝇的种群数量是公认的预防利什曼病的策略。然而，不分青红皂白地喷洒杀虫剂对所有昆虫区系都是有害的：包括许多有益的昆虫，如传粉者以及各种动物的猎物。使用信息素吸引昆虫进行种群监测、大规模诱捕和破坏交配都是控制虫害的既定方法。信息素提供了一定程度的特异性，允许有针对性的干预，并将对非目标物种的负面影响降至最低。沙蝇通过觅食的策略交配，大量的雄蝇和雌蝇聚集在树上或地上的小块上。信息素将启动和稳定这些集合，以进行有针对性的杀虫剂处理或蚊帐。这种方法已经在蚊子控制中进行了研究，由于它们靠近地面的行为比在空中传播的成群的行为更有效，预计对Lutzmyia Longipalpis更有效。Lutzmyia Longipalpis的性信息素和聚集信息素是由雄性产生的，对该物种的雌性和雄性都有吸引力。信息素的组成因地理位置的不同而不同，这导致了该昆虫的少量“化学类型”。在巴西，已经鉴定出产生(S)-9-甲基香叶烯-B((S)-9MGB)、(1S，3S，7R)-3-甲基-α-喜马烯((1S，3S，7R)-3MAH)或豆红烯为信息素的种群。完全化学合成这些化合物是不经济的，但通过阐明生物合成并确定昆虫中负责合成它们的酶，可以实现可持续的生物催化生产。因此，这项工作在促进病媒控制、从而减少利什曼病病例方面的潜在未来影响是显著的。在BBSRC的健康生物科学研究标题下的这个项目中，将使用一系列六个工作包来阐明这三种信息素化合物的生物合成。我们将利用不同化学类型的存在进行比较转录组和蛋白质组分析，这将在现有基因组数据的支持下指向每个种群中的生物合成酶。这种利用转录组、蛋白质组学和基因组数据的并行方法将最大限度地增加识别信息素生物合成机制的可能性。一旦鉴定出来，这些酶将被表达出来，用于功能鉴定和可持续生产信息素，用于大规模诱捕，并最终控制疾病。

Leishmaniases are a group of neglected tropical diseases caused by a protozoan parasite. In Central and South America the disease is spread by the blood-feeding sand fly, Lutzomyia longipalpis and related species. The disease is a particular challenge in Brazil, which has the highest incidence of leishmaniasis. Population control of the Lutzomyia longipalpis fly is a recognised strategy for preventing leishmaniasis. Indiscriminate spraying of insecticide is, however, harmful to all insect fauna: including many beneficial insects, such as pollinators as well as prey for a diverse range of animals.The use of pheromones to attract insects for population monitoring, mass trapping and mating disruption are all established approaches to pest control. Pheromones provide a level of specificity that allows targeted intervention and minimises negative effects on non-target species. Sand flies mate using a leking strategy, where large numbers of males and females accumulate on trees or patches on the ground. The pheromone will initiate and stabilise these assemblies for targeted insecticide treatment or netting. This approach has been investigated in mosquito control, and would be expected to be more effective with Lutzomyia due to their behaviour of leking close to the ground, rather than in airborne swarmsThe sex and aggregation pheromone of Lutzomyia longipalpis is produced by the male and is attractive to both females and males of the species. Composition of the pheromone varies with geographical location, which results in a small number of 'chemotypes' of the insect. In Brazil, populations producing (S)-9-methylgermacrene-B ((S)-9MGB), (1S,3S,7R)-3-methyl-alpha-himachalene ((1S,3S,7R)-3MAH), or sobralene as the pheromone have been identified. Total chemical synthesis of these compounds is uneconomic, but by elucidating the biosynthesis and identifying the enzymes responsible for their synthesis in the insect, sustainable biocatalytic production can be realised. The potential future impact of this work in facilitating vector control, and thereby reducing cases of leishmaniasis, is therefore significant. In this project, which comes under BBSRC's Bioscience for Health research heading, a series of six work packages will be used to elucidate the biosynthesis of the three pheromone compounds. We will exploit the existence of the different chemotypes for comparative transcriptome and proteome analysis, which - supported with existing genomic data - will point to the biosynthetic enzymes in each population. This parallel approach using transcriptomics, proteomics and genomic data will maximise the probability of identifying the pheromone biosynthetic machinery. Once identified, the enzymes will be expressed for functional characterisation and for sustainable production of the pheromone for mass trapping, and ultimately disease control.