Component of the SMC5-SMC6 complex, a complex involved in repair of DNA double-strand breaks by homologous recombination (PubMed:24207055). Transcription repressor that prevents expression of pathogenesis-related genes (PR) via histone modifications and binding negative cis-acting elements at their promoters (PubMed:16766691, PubMed:17369431, PubMed:20935179, PubMed:21320694). Negative regulator of hypersensitive response (HR) and systemic acquired resistance (SAR) required to dampen the basal expression of pathogenesis related (PR) genes (PubMed:10458608, PubMed:16766691, PubMed:17360504, PubMed:21149701). Functions synergistically with NTL9/CBNAC as negative regulator of pathogen-induced PR1 expression and basal resistance to a virulent strain of P.syringae (PubMed:22826500). Binds to the PR1 gene promoter to suppress defense response in the absence of pathogen challenge and is removed in response to induction (PubMed:21320694, PubMed:22826500). Regulates negatively both gene expression and DNA recombination during pathogen infection, thus being involved in short-term defense response and a long-term survival strategy (PubMed:17360504). Prevents effective immune responses that involve activation of DNA damage responses, probably by negatively regulating the DNA damage sensors RAD17 and ATR (PubMed:24207055). Negative regulator of defenses against the beet cyst nematode H.schachtii (PubMed:18321188). Interacts with SSN2 (PubMed:21320694). Binds to NTL9/CBNAC to promote its binding to promoters of target genes (PubMed:22826500). Component of the SMC5-SMC6 complex which consists at least of SMC5 and SMC6B. Interacts with RAD17 (PubMed:24207055). Also detectable in some fluorescent loci peripheral to the nucleus. Expressed at low levels in the veins. Accumulation of DNA damage leading to constitutively activated DNA damage responses (DDR) (PubMed:24207055). Increased basal expression of pathogenesis-related (PR) genes (e.g. PR1) and hypersensitive response (HR) (PubMed:16766691, PubMed:17369431, PubMed:17360504, PubMed:20935179, PubMed:21149701, PubMed:21320694). Chromatin modifications at the PR-1 promoter that mimic induction (e.g. AcH3 and MeH3K4) (PubMed:16766691). Dwarf plants with distorted leaves, reduced root length, early flowering and reduced fertility (PubMed:16766691, PubMed:17360504, PubMed:21320694). Decreased susceptibility to the beet cyst nematode H.schachtii (PubMed:18321188). Mutant plants display enhanced resistance to the bacterial pathogen P.syringae pv. tomato DC3000 (PubMed:22826500). Constitutively elevated levels of somatic homologous recombination (PubMed:17360504). Suppressor of the npr1-1 mutant phenotypes, including systemic acquired resistance (SAR) and normal levels of PR1 restoration (PubMed:10458608, PubMed:20935179).