APAF1 and infection: Plant proteins from this group with the central Apaf1/R/CED4-like NBD (TIR-NBARC-LRR, or TNLs) act as immune receptors that bind pathogen effectors directly or detect their manipulation of host physiology during infection (Monteiro and Nishimura, 2018; Tamborski and Krasileva, 2020).