Abstract Background: Phonotimpus pennimani (Araneae, Phrurolithidae) is a small-sized (3-5 mm) spider endemic to the Tacaná volcano in Chiapas, Mexico, where it is found in soil litter of cloud forests and coffee plantations. Its venom composition has so far not been investigated, partly because it is not a species of medical significance. However, it does have an important impact on the arthropod populations of its natural habitat. Methods: Specimens were collected in Southeastern Mexico (Chiapas) and identified taxonomically by morphological characteristics. A partial sequence from the mitochondrial gene coxI was amplified. Sequencing on the Illumina platform of a transcriptome library constructed from 12 adult specimens revealed 25 toxin or toxin-like genes. Transcripts were validated (RT-qPCR) by assessing the differential expression of the toxin-like PpenTox1 transcript and normalising with housekeeping genes. Results: Analysis of the coxI-gene revealed a similarity to other species of the family Phrurolithidae. Transcriptome analysis also revealed similarity with venom components of species from the families Ctenidae, Lycosidae, and Sicariidae. Expression of the toxin-like PpenTox1 gene was different for each developmental stage (juvenile or adult) and also for both sexes (female or male). Additionally, a partial sequence was obtained for the toxin-like PpenTox1 from DNA. Conclusion: Data from the amplification of the mitochondrial coxI gene confirmed that P. pennimani belongs to the family Phrurolithidae. New genes and transcripts coding for venom components were identified.

Resumen La supresión de moléculas de ácido ribonucleico mensajero (ARNm) mediante ARN interferente (ARNi) se ha propuesto como método de control de insectos plagas. El ARNi impide el desarrollo morfológico y funcional de los insectos y se considera altamente específico. En este estudio se buscaron receptores de insulina (InR) en Brevicoryne brassicae L. (Hemiptera: Aphididae) a partir del ARNm de pulgones, como primer paso para el diseño posterior de ARNi dirigido a la supresión de InR. A partir del ácido desoxirribonucleico complementario (ADNc) y mediante PCR anidada, se amplificó la región correspondiente a InR con dos pares de cebadores diseñados para Nilaparvata lugens (Homoptera: Delphacidae). No se logró identificar InR, en su lugar se predice la presencia de la proteína receptora Dip2A de unión a folistatina (FS) debido a que comparten regiones proteicas similares con los InR, involucradas en la traducción de señales en los insectos. Se sugiere continuar con la búsqueda de InR específicos para el pulgón, así como posibles cebadores para regiones de Dip2A, para lograr un ARNi altamente específico.

Abstract Suppression of messenger ribonucleic acid (mRNA) molecules by RNA interference (RNAi) has been proposed as a method for controlling insect pests. RNAi impedes the morphological and functional development of insects and is considered highly specific. In this study, insulin receptors (InR) were searched for in Brevicoryne brassicae L. (Hemiptera: Aphididae) from aphid mRNA, as a first step for further design of RNAi targeting InR suppression. From complementary deoxyribonucleic acid (cDNA) and by means of nested PCR, the region corresponding to InR was amplified with two pairs of primers designed for Nilapavata lugens (Homoptera: Delphacidae). InRs could not be identified. However, the presence of the follistatin-binding receptor protein Dip2A (FS) was predicted from the regions of similarity with the InRs that are involved in signal translation in insects. We recommend continuing the search for aphid specific InRs, as well as possible primers for Dip2A regions, to identify a highly specific RNAi.