(A) ASGV-infected in vitro grown plantlets. (B) Detection of Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple skin scar viroid (ASSVd) and Apple dimple fruit viroid (ADFVd) using RT-PCR with specific primers listed in Supplementary Table S1. ACTIN2 gene was used as an internal control. P, positive apple samples infected with ASGV, ACLSV, ASPV, ASSVd and ADFVd; H, healthy apple leaves. (C) Virus-free plantlets and Northern blotting to confirm ASGV elimination by thermotherapy. T11, T12, T25, T34, T35, T40, T45, T46, T47, T48, T55 and T60 represent regenerated apple plantlets after thermotherapy.