Nuclear Localization of HopA1 Is Required for Effector-Triggered Immunity.

Plant resistance proteins recognize cognate pathogen avirulence proteins (also named effectors) to implement the innate immune responses called effector-triggered immunity. Previously, we reported that from pv. strain 61 was identified as an gene for . Using a forward genetic screen approach, we cloned a specific TIR-NBS-LRR class disease resistance gene, (). Many resistance proteins indirectly recognize effectors, and RPS6 is thought to interact with indirectly by surveillance of an effector target. However, the involved target protein is currently unknown. Here, we show RPS6 is the only R protein that recognizes in Arabidopsis wild-type Col-0 accession. Both RPS6 and are co-localized to the nucleus and cytoplasm. is also distributed in plasma membrane and plasmodesmata. Interestingly, nuclear localization of is required to induce cell death as NES- suppresses the level of cell death in . In addition, in planta expression of led to defense responses, such as a dwarf morphology, a cell death response, inhibition of bacterial growth, and increased accumulation of defense marker proteins in transgenic Arabidopsis. Functional characterization of and RPS6 will provide an important piece of the ETI puzzle.