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RNAi-mediated knockdown of transformer-2 in the predatory mite Metaseiulus occidentalis via oral delivery of double-stranded RNA
- Pomerantz, Aaron F., Hoy, Marjorie A.
- Experimental & applied acarology 2015 v.65 no.1 pp. 17-27
- Metaseiulus occidentalis, RNA interference, biological control agents, double-stranded RNA, eggs, gene expression, genes, genetic engineering, insects, pests, predatory mites, progeny, reproduction, sex determination, sex ratio, virgin females
- Little is known about the process of sex determination at the molecular level in Metaseiulus occidentalis, a parahaploid species and natural enemy of phytophagous pest mites. Detailed knowledge of the sex-determination pathway could allow genetic manipulation of M. occidentalis to produce more female offspring, which could improve its effectiveness as a biological control agent. RNA interference is useful for assessing the function of putative sex-determination genes by reducing or eliminating gene expression. In many insect species the transformer-2 (tra-2) gene is an upstream regulatory element in the sex-determination cascade, and knockdown of tra-2 expression can alter the sex ratio. We assessed whether oral delivery of tra-2 double-stranded RNA to M. occidentalis virgin females would affect the sex of her progeny. Females that ingested tra-2 dsRNA produced significantly fewer eggs compared to control females suggesting that tra-2 is somehow involved in reproduction by females. However, the sex ratio of the few progeny that were laid was not altered, so it is unclear whether tra-2 is involved in sex determination. This is an initial step towards elucidating the molecular components of sex determination in M. occidentalis.