Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100 1400, Vienna, Austria.
Laboratory of Virology, Wageningen University and Research, 6708, PB, Wageningen, The Netherlands.
BMC Microbiol. 2018 Nov 23;18(Suppl 1):143. doi: 10.1186/s12866-018-1297-2.
The management of the tsetse species Glossina pallidipes (Diptera; Glossinidae) in Africa by the sterile insect technique (SIT) has been hindered by infections of G. pallidipes production colonies with Glossina pallidipes salivary gland hypertrophy virus (GpSGHV; Hytrosaviridae family). This virus can significantly decrease productivity of the G. pallidipes colonies. Here, we used three highly diverged genes and two variable number tandem repeat regions (VNTRs) of the GpSGHV genome to identify the viral haplotypes in seven Glossina species obtained from 29 African locations and determine their phylogenetic relatedness.
GpSGHV was detected in all analysed Glossina species using PCR. The highest GpSGHV prevalence was found in G. pallidipes colonized at FAO/IAEA Insect Pest Control Laboratory (IPCL) that originated from Uganda (100%) and Tanzania (88%), and a lower prevalence in G. morsitans morsitans from Tanzania (58%) and Zimbabwe (20%). Whereas GpSGHV was detected in 25-40% of G. fuscipes fuscipes in eastern Uganda, the virus was not detected in specimens of neighboring western Kenya. Most of the identified 15 haplotypes were restricted to specific Glossina species in distinct locations. Seven haplotypes were found exclusively in G. pallidipes. The reference haplotype H1 (GpSGHV-Uga; Ugandan strain) was the most widely distributed, but was not found in G. swynnertoni GpSGHV. The 15 haplotypes clustered into three distinct phylogenetic clades, the largest contained seven haplotypes, which were detected in six Glossina species. The G. pallidipes-infecting haplotypes H10, H11 and H12 (from Kenya) clustered with H7 (from Ethiopia), which presumably corresponds to the recently sequenced GpSGHV-Eth (Ethiopian) strain. These four haplotypes diverged the most from the reference H1 (GpSGHV-Uga). Haplotypes H1, H5 and H14 formed three main genealogy hubs, potentially representing the ancestors of the 15 haplotypes.
These data identify G. pallidipes as a significant driver for the generation and diversity of GpSGHV variants. This information may provide control guidance when new tsetse colonies are established and hence, for improved management of the virus in tsetse rearing facilities that maintain multiple Glossina species.
在非洲，通过不育昆虫技术（SIT）对采采蝇物种 Glossina pallidipes（双翅目；舌蝇科）进行管理，受到 Glossina pallidipes 唾液腺肥大病毒（GpSGHV；Hytrosaviridae 科）感染采采蝇生产群的阻碍。这种病毒会显著降低采采蝇种群的生产力。在这里，我们使用 GpSGHV 基因组的三个高度分化的基因和两个可变数量串联重复区（VNTRs）来鉴定来自 29 个非洲地点的 7 种采采蝇中病毒的单倍型，并确定它们的系统发育关系。
使用 PCR 在分析的所有 Glossina 物种中都检测到了 GpSGHV。在 FAO/IAEA 昆虫害虫控制实验室（IPCL）中从乌干达（100%）和坦桑尼亚（88%）殖民的 G. pallidipes 中发现了最高的 GpSGHV 流行率，而在坦桑尼亚（58%）和津巴布韦（20%）的 G. morsitans morsitans 中发现了较低的流行率。虽然在乌干达东部的 25-40%的 G. fuscipes fuscipes 中检测到了 GpSGHV，但在邻国肯尼亚的标本中未检测到该病毒。在确定的 15 个单倍型中，大多数都局限于特定的 Glossina 物种在不同的位置。仅在 G. pallidipes 中发现了 7 个单倍型。参考单倍型 H1（GpSGHV-Uga；乌干达株）分布最广，但在 G. swynnertoni GpSGHV 中未发现。15 个单倍型聚集成三个不同的系统发育枝，最大的包含 7 个单倍型，在六种 Glossina 物种中检测到。感染 G. pallidipes 的单倍型 H10、H11 和 H12（来自肯尼亚）与 H7（来自埃塞俄比亚）聚类，这可能对应于最近测序的 GpSGHV-Eth（埃塞俄比亚）株。这四个单倍型与参考 H1（GpSGHV-Uga）的分化最大。单倍型 H1、H5 和 H14 形成三个主要的基因进化中心，可能代表了 15 个单倍型的祖先。
这些数据表明 G. pallidipes 是 GpSGHV 变体产生和多样性的重要驱动因素。当建立新的采采蝇群时，这些信息可能提供控制指导，因此有助于在维持多种采采蝇物种的采采蝇饲养设施中更好地管理病毒。
