We used our screening system and previously identified ACE (Avr/Cf- elicited) genes [30]–[31] to identify seven genes that are required for the HR and nonhost resistance to Xoo. Silencing of these genes abolished or markedly compromised the HR and nonhost resistance (Table 1, Figs. 5A, 7). Notably, four of the seven genes were required for Cf-4/Avr4-dependent HR [30]–[31]. Thus, regulatory pathways of nonhost resistance to the bacterial pathogen Xoo and those of ETI (Cf-4/Avr4) partially overlap, which supports the hypothesis that nonhost and host resistance are mechanistically similar [8].