Infection by the microsporidium of Clado Nosema/Vairimorpha in pupal parasitoids

Abstract: The sugarcane borer, Diatraea saccharalis is one of the hosts more used for parasitoid pupal multiplication in Brazil. The parasitoids pupal of Trichospilus diatraeae and Palmistichus elaeisis are generalist natural enemies with potential to suppress populations of diverse families of lepidopteran pests. The success in the utilization of these natural enemies in the field is directly related to the capacity of search of the host, this capacity might be affected by the presence of the pathogens. In this context, the aim of this essay was to detect the presence of intracellular parasites of Phylum Microsporidia. These pathogens may cause morphological and behavioral alterations. The presence of infection was verified by microscopy and was confirmed by amplification of region small subunit (SSU) of ribosomal RNA using universal primers for microsporidia of Nosema sp. The purified PCR products were submitted to sequencing, and the sequences that had been obtained were edited and aligned with the sequences in a Genbank database. In this way, it was possible to verify the presence of intracellular parasites in T. diatraeae, P. elaeisis and D. saccharalis pertaining to Clade Nosema/Vairimorpha. However, this is the first one report about detection of the microsporidia in the parasitoids T. diatraeae and P. elaeisis.

摘要：甘蔗螟虫（Diatraea saccharalis）是巴西境内用于寄生蜂蛹繁育的最常用寄主之一。螟虫蛹寄生蜂（Trichospilus diatraeae）与榄脂翅蚜小蜂（Palmistichus elaeisis）均为广食性天敌，具备抑制多科鳞翅目害虫种群的应用潜力。这类天敌在田间的应用成效，直接与其寄主搜寻能力息息相关，而该能力可能会因病原体的存在而受到影响。在此研究背景下，本研究旨在检测微孢子虫门（Microsporidia）胞内寄生虫的存在。此类病原体可引发宿主的形态及行为改变。研究通过显微镜观察验证了感染的存在，并利用针对微粒子虫属（Nosema sp.）微孢子虫的通用引物，扩增核糖体RNA小亚基（SSU）区域予以确认。将纯化后的PCR产物进行测序，对所得序列进行编辑，并与GenBank数据库中的序列进行比对分析。通过上述步骤，得以确认在T. diatraeae、P. elaeisis以及D. saccharalis体内均存在属于Nosema/Vairimorpha演化支的胞内寄生虫。不过，本研究是首次在寄生蜂T. diatraeae与P. elaeisis体内检测到微孢子虫的学术报道。