Nicotiana benthamiana as a model system for dissecting plant-pathogen interactions

<i>Nicotiana benthamiana</i> is widely used as a model plant for studying plant-pathogen interactions owing to its genetic background and experimental accessibility. Its allopolyploid genome, high susceptibility to diverse pathogens, and distinct composition of RNA silencing-related genes provide a suitable system for investigating host responses during infection. Studies in <i>N.benthamiana</i> have enabled detailed analyses of interactions with viruses, viroids, bacteria, fungi, and oomycetes, and have contributed to the characterization of antiviral RNA silencing, pattern-triggered immunity (PTI), effector-triggered immunity (ETI), and MAPK-mediated signaling pathways. Premature transcriptional termination resulting in a nonfunctional <i>NbRDR1</i> constitutes a key factor influencing antiviral RNA silencing regulation and host-virus interactions in this species. <i>N.benthamiana</i> has also been used to dissect immune receptor-mediated signaling and downstream defense responses to non-viral pathogens, including reactive oxygen species production and programmed cell death. In addition, the availability of virus-induced gene silencing and <i>Agrobacterium</i>-mediated transient expression systems has facilitated functional analyses and comparative studies across plant species. This review integrates molecular insights from diverse pathosystems and evaluates limitations relevant to interpreting results obtained in <i>N.benthamiana</i>.