Expression profiles of Api-piwi and Api-ago3 genes of A. pisum in the four reproductive morphs.

Expression levels of the eight Api-piwi (1–8) and the two Api-ago3 (a and b) transcripts were investigated by semi-quantitative RT-PCR on total RNA of adults collected 48 h after adult moult of the four reproductive morphs: parthenogenetic virginoparae females (Vp), parthenogenetic sexuparae females (Sxp), sexual oviparae females (Ovp) and sexual males (M) (See Figure S1 for gel photography). Expression of Api-piwi and Api-ago3 genes in the different morphs was normalised against the gene encoding ribosomal protein 7 (Api-rpl7) as a reference gene [45]. The ratio between the expression of the amplified gene and of the Api-rpl7 reference gene was calculated to normalise for variations in experimental conditions. For each morph, gene expression was measured from three batches of 10 adult aphids resulting from three independent biological experiments. For each gene, an average normalised expression level was calculated for each reproductive morph. In order to test the significance of variation of expression level, the data were subjected to arc-sine transformation to analyse variance. Letters indicate statistical significant similar or different expression levels in the samples.