The Arabidopsis Elongator Complex Subunit2 Epigenetically Regulates Plant Immune Responses  

Abstract

The Arabidopsis thaliana Elongator complex subunit2 (ELP2) genetically interacts with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (NPR1), a key transcription coactivator of plant immunity, and regulates the induction kinetics of defense genes. However, the mechanistic relationship between ELP2 and NPR1 and how ELP2 regulates the kinetics of defense gene induction are unclear. Here, we demonstrate that ELP2 is an epigenetic regulator required for pathogen-induced rapid transcriptome reprogramming. We show that ELP2 functions in a transcriptional feed-forward loop regulating both NPR1 and its target genes. An elp2 mutation increases the total methylcytosine number, reduces the average methylation levels of methylcytosines, and alters (increases or decreases) methylation levels of specific methylcytosines. Interestingly, infection of plants with the avirulent bacterial pathogen Pseudomonas syringae pv tomato DC3000/avrRpt2 induces biphasic changes in DNA methylation levels of NPR1 and PHYTOALEXIN DEFICIENT4 (PAD4), which encodes another key regulator of plant immunity. These dynamic changes are blocked by the elp2 mutation, which is correlated with delayed induction of NPR1 and PAD4. The elp2 mutation also reduces basal histone acetylation levels in the coding regions of several defense genes. Together, our data demonstrate a new role for Elongator in somatic DNA demethylation/methylation and suggest a function for Elongator-mediated chromatin regulation in pathogen-induced transcriptome reprogramming.

Arabidopsis HOOKLESS1 regulates responses to pathogens and abscisic acid through interaction with MED18 and acetylation of WRKY33 and ABI5 chromatin

“…The elongator complex subunit 2 (ELP2) and ELP3 regulate resistance to P. syringae pv maculicola (Psm) ES4326 through their HAT activity on defense-related genes (Defraia et al, 2013;Wang et al, 2013). As shown in this study, HLS1 modulates H3 acetylation on specific loci required for plant immunity and ABA responses.…”

“…GCN5 in Arabidopsis thaliana is implicated in plant developmental functions, such as floral meristem formation or root meristem differentiation (Bertrand et al, 2003;Kornet and Scheres, 2009), as well as responses to cold, light, or iron homeostasis (Vlachonasios et al, 2003;Benhamed et al, 2006;Xing et al, 2015). Histone acetyltransferases also play vital roles in plant resistance to the bacterial pathogen Pseudomonas syringae pv tomato DC3000 (Pst DC3000) (Defraia et al, 2013;Wang et al, 2013;Singh et al, 2014).…”

Revealing Shared and Distinct Gene Network Organization in Arabidopsis Immune Responses by Integrative Analysis

“…Therefore, M63 gene activities could quickly influence the entire network. Moreover, we observed a recently identified epigenetic regulator in M63, ELONGATOR COMPLEX SUBUNIT2, that is essential for rapid transcriptional reprogramming in ETI (Wang et al, 2013). Taken together, M63 implies a potential role of chromatin dynamics in ETI, although further validation is required.…”

The 2′-O-methyladenosine nucleoside modification gene OsTRM13 positively regulates salt stress tolerance in rice

“…According to the PlantRNA database (Cognat et al , 2013), more than 600 tRNA genes are present in the Arabidopsis genome coding for ca 200 tRNA unique sequences, of which none is associated with information of modified nucleosides. Nevertheless, several mutants of tRNA nucleoside modification genes have been described in Arabidopsis, many of which result in retarded plant growth (Chen et al , 2006; Hu et al , 2010; Zhou et al , 2013), impaired immune response (Wang et al , 2013) or abrogated abiotic stress tolerance (Zhou et al , 2013; Burgess et al , 2015). …”