AvrRxo1 was screened out as a suppressor of non-host resistance in Nicotiana benthamiana.
(A) Symptoms caused by Xoo strains PXO99A (wild type) (1), pHM1 (2), 2C10 (clone of RS105 genomic library) (3), 8E07 (clone of RS105 genomic library) (4), pHMavrRxo1RS105 (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: pHMavrRxo1RS105, pHMavrRxo1RS85, pHMavrRxo1SDAU-1, pHMavrRxo1JSB2-24 and pHMavrRxo1HNB8-47. 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 PXO99A containing avrRxo1 gene results in a hypersensitive response at 2 dpi. PXO99A and PXO99A (pHM1) produced no reaction. (C) Symptoms caused by five AvrRxo1 clones in Xoo strains PXO99A (1) pHM1, (2) pHMavrRxo1RS105 (3), pHMavrRxo1RS85 (4), pHMavrRxo1SDAU-1 (5), pHMavrRxo1JSB2-24 (6), pHMavrRxo1HNB8-47 (7), and PXO61 (8) in N. benthamiana. All experiments were repeated three times with similar results.