Figure 1. AvrRxo1 was screened out as a suppressor of non-host resistance in Nicotiana benthamiana.

(A) Symptoms caused by Xoo strains PXO99^A (wild type) (1), pHM1 (2), 2C10 (clone of RS105 genomic library) (3), 8E07 (clone of RS105 genomic library) (4), pHMavrRxo1_RS105 (5) and MgCl₂ (10 mM) (6) in Nicotiana benthamiana. Xoo strains [1×10⁸ colony-forming units (cfu)/mL] were inoculated to N. benthamiana (4–6 weeks old) with a needleless syringe, and symptoms were measured at 2 days post-inoculation (dpi). (B) The phenotype of interactions between maize lines B73 and five AvrRxo1 clones: pHMavrRxo1_RS105, pHMavrRxo1_RS85, pHMavrRxo1_SDAU-1, pHMavrRxo1_JSB2-24 and pHMavrRxo1_HNB8-47. Xoo strains [1×10⁸ cfu/mL] were infiltrated into B73 (4 weeks old) with a needleless syringe, and symptoms were measured at 2 dpi. Infiltration of B73 with PXO99^A containing avrRxo1 gene results in a hypersensitive response at 2 dpi. PXO99^A and PXO99^A (pHM1) produced no reaction. (C) Symptoms caused by five AvrRxo1 clones in Xoo strains PXO99^A (1) pHM1, (2) pHMavrRxo1_RS105 (3), pHMavrRxo1_RS85 (4), pHMavrRxo1_SDAU-1 (5), pHMavrRxo1_JSB2-24 (6), pHMavrRxo1_HNB8-47 (7), and PXO61 (8) in N. benthamiana. All experiments were repeated three times with similar results.