RT Journal Article
SR Electronic
T1 Arabidopsis Histone Methyltransferase SDG8 Mediates Induction of the Jasmonate/Ethylene-Pathway Genes in Plant Defense Response to Necrotrophic Fungi
JF Plant Physiology
JO Plant Physiol.
FD American Society of Plant Biologists
SP pp.110.161497
DO 10.1104/pp.110.161497
A1 Berr, Alexandre
A1 McCallum, Emily J.
A1 Alioua, Abdelmalek
A1 Heintz, Dimitri
A1 Heitz, Thierry
A1 Shen, Wen-Hui
YR 2010
UL http://www.plantphysiol.org/content/early/2010/09/13/pp.110.161497.abstract
AB As sessile organisms, plants have to endure a wide variety of biotic and abiotic stresses, and accordingly have evolved intricate and rapidly inducible defense strategies associated with the activation of a battery of genes. Among other mechanisms, changes in chromatin structure are thought to provide a flexible, global and stable means for regulation of gene transcription. In support of this idea, we demonstrate here that the Arabidopsis thaliana histone-methyltransferase SET DOMAIN GROUP8 (SDG8) plays a crucial role in plant defense against fungal pathogens by regulating a subset of genes within the jasmonic acid (JA) and/or ethylene (ET) signaling pathway. We show that the loss-of-function mutant sdg8-1 displays reduced resistance to the necrotrophic fungal pathogens Alternaria brassicicola and Botrytis cinerea. While levels of JA, a primary phytohormone involved plant defense, and camalexin, a major phytoalexin against fungal pathogens, remain unchanged or even above normal levels in sdg8-1, induction of several defense genes within the JA/ET signaling pathway is severely compromised in response to fungal infection or JA treatment in mutant plants. Both downstream genes and, remarkably, also upstream MAPK-kinase genes MKK3 and MKK5 are misregulated in sdg8-1. Accordingly, chromatin immunoprecipitation analysis shows that sdg8-1 impairs dynamic changes of H3K36 methylation at defense marker genes as well as at MKK3 and MKK5, which normally occurs upon infection with fungal pathogens or methyl-JA treatment in wild-type plants. Our data indicates that SDG8-mediated H3K36 methylation may serve as a memory of permissive transcription for a subset of defense genes allowing rapid establishment of transcriptional induction.