Molecular Parallels: Innate Immunity and Pathogen Strategies in Plants and Animals

Both plants and animals have developed a sophisticated two-tiered innate immune system. This involves an initial recognition of microbial patterns conserved on the cell surface (PAMP-triggered immunity) and a subsequent more specific intracellular recognition of pathogenic effectors or their activities (effector-triggered immunity). A common fundamental feature is the use of NLR-like intracellular receptors to detect insider threats. Both plant NLRs (receptors containing nucleotide-binding domains and leucine-rich repeats) and animal NLRs (NOD-like receptors) share a modular tripartite architecture, typically featuring a central nucleotide-binding domain (NBD/NOD) and C-terminal leucine-rich repeats (LRRs). The NBD/NOD is crucial for facilitating the exchange of ADP/ATP, acting as a molecular switch to promote oligomerization and activation of NLRs in both kingdoms. In this review, we summarize the similarities and differences between plant and animal molecular perception and immunity mechanisms. Additionally, we highlight the fact that some human pathogens can infect plants, and crucially, some plant pathogens are capable of causing disease in humans. This suggests conserved molecular strategies to invade and manipulate host cells belonging to different biological kingdoms, uncovering that plant and human pathology may benefit from future investigations in their respective fields.