Fig. 3

Effects of the Candidatus Phytoplasma ziziphi ncSecPs (Pzi-ncSecPs) on hypersensitive cell death response (HR) in Nicotiana benthamiana. a Six Pzi-ncSecPs inhibited the Bax- and INF1-triggered HR. A total of 25 Pzi-ncSecPs were examined with the HR suppression assays, as described in the Methods section, with the green fluorescent protein (GFP) as the negative control. HR symptoms were recorded five days post-Bax- or INF1-infiltration. The HR suppression activity of each Pzi-ncSecP was evaluated with the suppression number/infiltration number (CDS/I) index. The data from three independent experiments were combined as averages. Only the Pzi-ncSecPs exhibiting suppression (CDS/I ≥ 50%) are shown. Asterisks in columns indicate statistically significant differences based on Student’s t-test (*, P < 0.05; **, P < 0.01). b HR suppression phenotypes caused by the Pzi-ncSecPs. Photos were taken five days after Bax- or INF1-infiltration. c Pzi-ncSecP16 suppressed Bax- and INF1-induced H₂O₂ accumulation. GFP was used as the negative control. Similar results were observed for Pzi-ncSecP3, 9, 12, 14, and 22 (Additional file 3: Figure S1). The N. benthamiana leaves were detached two days after Bax- or INF1-infiltration, and subsequently stained with DAB