NPR1 and infection: The loss of ALD1-dependent signaling does not make npr1 and sid2 mutants more susceptible to infection with an attenuated strain, virulent strains, and an avirulent strain of P. syringae carrying AvrRpm1. However, to fully activate the immune response to an avirulent P. syringae strain carrying AvrRpt2 requires ALD1 in addition to NPR1 and ICS1/SID2.