(A) The phenotype of interactions between maize lines B73 and deletion mutants of AvrRxo1. Infiltration of B73 with PXO99A containing avrRxo1 gene results in HR at 2 dpi. PXO99A (pHM1) as negative control. Fragments AvrRxo1(17–421), AvrRxo1(52–421), AvrRxo1(109–421), AvrRxo1(140–421), AvrRxo1(186–421), AvrRxo1(1–159), AvrRxo1(1–193), AvrRxo1(1–278), AvrRxo1(1–373), AvrRxo1(1–412), AvrRxo1(1–417), and AvrRxo1(1–418), abolished induce HR on B73, while fragments AvrRxo1(1–419) and AvrRxo1(1–420) produce HR on B73 at 2 dpi. (B) Suppressions of non-host HR by deletion mutants of AvrRxo1 in N. benthamiana. Infiltration of N. benthamiana with PXO99A (pHM:avrRxo1) (1) and PXO99A (pHM1) (2) as control. Fragments AvrRxo1(17–421) (3), AvrRxo1(52–421) (4), AvrRxo1(109–421) (5), AvrRxo1(140–421) (6), AvrRxo1(186–421) (7), AvrRxo1(1–412) (8), AvrRxo1(1–417) (9), AvrRxo1(1–418) (10), AvrRxo1(1–419) (11), AvrRxo1(1–420) (12) did not suppress the non-host HR caused by PXO99A in N. benthamiana. RT-PCR was used to confirm the expression of avrRxo1 in inoculated leaves. All experiments were repeated three times with similar results.