Analysis of adenine methylation on the secondary endosymbiont’s transposase gene. Schematic representation of the A1 fragment (Regiella insecticola transposase gene, accession number WP_006705102.1). Orange circle indicates the position of the examined adenine methylation site; arrows indicate primer positions and orientations (a). PCR amplification of digested gDNA using A1F1 and A1R1 primers from orange and green variants (24 individual aphids) (b-c and f-g). PCR using A1F2 and A1R1 primers on orange and green variants (24 individual aphids) (d-e and h-i). Dot-spot hybridization (using A1-based DIG probe) on gDNA extracted from A. pisum (green and orange variants) and Myzus persicae (j). Comparison of cDNA expression levels in the orange and green variants (k) of the A1 fragment (upper panel), and R. insecticola 16S (lower panel).