Nuclear pore complexes play an important role in plant osmotic tolerance through the transport of immune response-related factors

We previously reported a wide variation in salt tolerance among Arabidopsis thaliana accessions and identified ACQOS as the causal gene responsible for the acquired osmotolerance induced after mild salt stress. ACQOS is conserved among osmosensitive accessions including Col-0 and functions as a negative regulator of the acquired osmotolerance. However, it is unclear how ACQOS triggers the autoimmunity in response to osmotic stress. To reveal the mechanism, we performed a screening of acquired osmotolerant (aot) mutants from EMS-mutagenized Col-0 seeds and isolated aot19. The aot19 displayed acquired osmotolerance and reduction in expression levels of pathogenesis-related genes compared with wild type. As results of genetic analyses, we found a splicing error-inducing mutation in one gene at the causal locus in aot19. The T-DNA inserted mutant improved osmotolerance as well as aot19, furthermore, the introduction of the WT gene into aot19 restored osmo-sensitive phenotype as in Col-0. This gene encodes a component of nuclear pore complexes. AOT19 may play an important role in transport of proteins or mRNAs related to immune response activated by osmotic stress.