Epigenetic variation in Arabidopsis disease resistance

Abstract

Plant pathogen resistance is mediated by a large repertoire of resistance (R) genes, which are often clustered in the genome and show a high degree of genetic variation. Here, we show that an Arabidopsis thaliana R-gene cluster is also subject to epigenetic variation. We describe a heritable but metastable epigenetic variant bal that overexpresses the R-like gene At4g16890 from a gene cluster on Chromosome 4. The bal variant and Arabidopsis transgenics overexpressing the At4g16890 gene are dwarfed and constitutively activate the salicylic acid (SA)-dependent defense response pathway. Overexpression of a related R-like gene also occurs in the ssi1 (suppressor of SA insensitivity 1) background, suggesting that ssi1 is mechanistically related to bal.

Next-Generation Systemic Acquired Resistance

“…For instance, Arabidopsis responds to infection by PstDC3000 by hypomethylation of genomic DNA (Pavet et al, 2006). Furthermore, inbreeding of the Arabidopsis decrease in DNA methylation1 mutation, causing genome-wide DNA hypomethylation, gives rise to a heritable but metastable defense allele, called bal1, which confers NPR1-dependent resistance (Stokes et al, 2002;Yi and Richards, 2009). Hence, DNA hypomethylation can cause epigenetic inheritance of disease resistance.…”

Epigenetic Control of a Transcription Factor at the Cross Section of Two Antagonistic Pathways

“…The chromatin-remodeling factor (DDM1) and DNA methylation are involved in plant pathogen interactions controlled by the BAL locus. 35 Histone deacetylases (HDA) were implicated in maize responses to pathogenic fungi and in JA, ethylene, and Alternaria brassicicola induced responses in Arabidopsis. [36][37][38] Histone deacetylase activity of HDA19 correlated with PR gene expression and with altered pathogen resistance to A. brassicicola in hda19 mutants.…”

Control of Development and Transposon Movement by DNA Methylation in Arabidopsis thaliana

“…The change in transcription and associated developmental variation was often heritable over multiple generations. Such an inheritance of differential epigenetic state is an enigmatic phenomenon found often in plants (Jacobsen and Meyerowitz 1997;Cubas et al 1999;Kakutani et al 1999;Soppe et al 2000Soppe et al , 2002Stokes et al 2002). Similar inheritance of epigenetic variations has also been reported for some alleles of mammalian genes (Whitelaw and Martin 2001;Rakyan et al 2003).…”

“…Like fwa, this phenotype is stably inherited over multiple generations even after introduction into wild-type DDM1 background (Stokes et al 2002). Details of the inheritance of bal phenotype are described in another chapter (Yi et al, this volume).…”

“…bal, sup-LIKE, AND ag-LIKE Another ddm1-induced developmental abnormality, bal, maps to a locus with clustered disease resistance genes; and it is also associated with overexpression of sequences within this region (Stokes et al 2002). Like fwa, this phenotype is stably inherited over multiple generations even after introduction into wild-type DDM1 background (Stokes et al 2002).…”