Fig. 2: PxAPN1 and PxAPN3a are functional Cry1Ac receptors in P. xylostella.

a Detection of Cry1Ac binding to Sf9 cells expressing PxAPN proteins by immunolocalization. Gray panels: differential interference contrast (DIC) microscopy views; green panels: GFP-expression fluorescent signal; red panels: Cry1Ac-binding fluorescent signal. Mixed color panels: merged images from both the green and red fluorescent channels. The scale bar is 20 μm. b Susceptibility to a series of concentrations of Cry1Ac toxin (0.1 nM to 1 µM) in untransfected Sf9 cells (control), Sf9 cells transfected with only an empty expression vector (NON) and PxAPN-expressing Sf9 cells after 24 h incubation. c RNAi-mediated silencing of PxAPN1 or PxAPN3a is expressed relative to transcript level for each gene at time 0 h, which are displayed as expression fold changes and color-coded according to the gradient. d Susceptibility to Cry1Ac protoxin in DBM1Ac-S larvae injected with buffer or dsEGFP, dsPxAPN1, dsPxAPN3a or a multiple gene mixture (dsPxAPN1 and dsPxAPN3a). e Non-linear log dose–response curves for P. xylostella larvae from the susceptible DBM1Ac-S strain, the CRISPR/Cas9-mediated PxAPN1 and PxAPN3a knockout strains PxAPN1KO and PxAPN3aKO, and the near-isogenic resistant strain NIL-R exposed to Cry1Ac protoxin. f Interstrain allelic complementation tests with diagnostic doses of Cry1Ac protoxin (10 mg/L). F1 progeny were produced by crossing one susceptible and three resistant strains in all pair-wise combinations. Data are presented as mean values (c) and mean values ± SEM (b, d, f), n = 6 (b, c), n = 3 (d), and n = 5/10 (f) biologically independent samples, *p < 0.05, **p < 0.01, ***p < 0.001, ns, not significant, one-way ANOVA with Holm–Sidak’s test was used in (c), (d), and (f) for comparison. Images in (a) are representative micrographs of three independent experiments that produced similar results. Source data are provided as a Source Data file.