The arabidopsis NSL2 negatively controls systemic acquired resistance via hypersensitive response

Abstract

The Arabidopsis nsl2 (necrotic spotted lesion 2) mutant, which has been originally reported as the cad1 (constitutively activated cell death 1), shows a phenotype that mimics a hypersensitive response (HR)-like cell death. The NSL2 protein is suggested to negatively control the salicylic acid (SA)-mediated pathway of HR-like cell death in plant immunity. The induction of systemic acquired resistance (SAR) results in the induction of pathogenesis-related (PR) genes in systemic organs triggered by the local HR. In this report, we establish a NSL2 knockdown system in transgenic Arabidopsis based on constitutive or dexamethasone (DEX)-induced RNAi. The former showed a nsl2-like phenotype. In DEX-induced RNAi, localized knockdown resulted in the induction of PR1 gene expression and the restriction of bacterial growth in both DEX-treated and systemic leaves. These results indicate that NSL2 negatively controls SAR via HR.