The HAC1 histone acetyltransferase promotes leaf senescence and regulates the expression of ERF022

Abstract

Nutrient remobilization during leaf senescence nourishes the growing plant. Understanding the regulation of this process is essential for reducing our dependence on nitrogen fertilizers and increasing agricultural sustainability. Our laboratory is interested in chromatin changes that accompany the transition to leaf senescence. Previously, darker green leaves were reported for Arabidopsis thaliana hac1 mutants, defective in a gene encoding a histone acetyltransferase in the CREB‐binding protein family. Here, we show that two Arabidopsis hac1 alleles display delayed age‐related developmental senescence, but have normal dark‐induced senescence. Using a combination of ChIP‐seq for H3K9ac and RNA‐seq for gene expression, we identified 43 potential HAC1 targets during age‐related developmental senescence. Genetic analysis demonstrated that one of these potential targets, ERF022 , is a positive regulator of leaf senescence. ERF022 is regulated additively by HAC1 and MED25, suggesting MED25 may recruit HAC1 to the ERF022 promoter to increase its expression in older leaves.

Gene expression changes occurring at bolting time are associated with leaf senescence in Arabidopsis

“…Ethylene, abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), and reactive oxygen species (ROS) are known to promote both age-dependent and dark-induced LS (Jing et al, 2005;Khanna-Chopra, 2012;Lim et al, 2007;Yuehui et al, 2002;Zhang et al, 2013Zhang et al, , 2020Zhao et al, 2017). Many genetic regulators of LS have also been identified (Ay et al, 2014;Brusslan et al, 2015;Chen, Lu, et al, 2016;Hinckley et al, 2019;Keqiang et al, 2008;Liu et al, 2019;Wang et al, 2019;Woo et al, 2013;Woo et al, 2019;Zheng et al, 2020). There are multiple large TF families that are commonly associated with age-dependent and dark-induced LS (WRKY, NAC, ERF) (Bakshi & Oelmüller, 2014;Jiang et al, 2017;Kim et al, 2016;Koyama, 2014;Koyama et al, 2013;.…”

Genetic Characterization of Russian Rapeseed Collection and Association Mapping of Novel Loci Affecting Glucosinolate Content

“…According to rapeseed genome annotation, the two SNPs significantly associated with glucosinolate concentrations in the Russian rapeseed lines are localized within the intergenic region between the genes encoding the transcription termination factor MTERF2 chloroplastic-like and the U-box domain-containing protein 35-like (Table S4). Furthermore, the analysis of the genes located within the window of 100 kb upstream and downstream of the two SNPs significantly associated with glucosinolate content revealed the genes encoding the histone acetyltransferase HAC1 and BES1/BZR1 homolog protein 4-like (Table S5), respectively, linked to glucosinolate content in the previous studies [45,46]. Among the five marginally significant SNPs, one was annotated as a missense variant (SA1_4407039) and one as a synonymous variant (SA6_21541176) within the genes encoding the uncharacterized protein BNAA01G06520D and derlin-2.1 protein, respectively (Table S4).…”

“…Specifically, two significant markers, SA7_26967214 and SA7_26967217, were located 38.1 and 75.3 kb downstream of the genes encoding the histone acetyltransferase HAC1 and BES1/BZR1 homolog protein 4-like, respectively (Table S5). The HAC1 encoding histone acetyltransferase was shown to be involved in leaf senescence in plants [46]. Notably, the HAC1 Arabidopsis thaliana knockout mutants demonstrated the repression of genes involved in the metabolism of glucosinolate [46].…”

“…The HAC1 encoding histone acetyltransferase was shown to be involved in leaf senescence in plants [46]. Notably, the HAC1 Arabidopsis thaliana knockout mutants demonstrated the repression of genes involved in the metabolism of glucosinolate [46]. The BZR family proteins include transcription factors involved in the brassinosteroid signaling pathway.…”

Integrative inference of transcriptional networks in Arabidopsis yields novel ROS signalling regulators

“…Among the novel ROS TFs newly identified by our phenotyping assays, WRKY55, WRKY47, AT2G33710 [ERF] and AT5G57150 [bHLH] had previously not been associated with any function. Other validated novel ROS TFs are known to function in high-light stress tolerance or acclimation responses (NAC102, BME3 [GATA family] 33-35 ), age-triggered senescence (WRKY45, ERF022 [AP2/EREBP]; 43,44 ), response to phosphate starvation (WRKY45, PHL1 [G2 family]; 45,46 ), submergence stress (WRKY45; 47 ), glucosinolate (antimicrobial compounds involved in plant immunity) biosynthesis (MYB51, MYB122; 48 ), brassinosteroid signaling (BEH2 [BES1 TF family]; 49 ), phytochrome-dependent light signaling (SCL13 [GRAS family]; 50 ), hypocotyl growth (BEH2 [BES1 family]; 51 ), seed germination (BME3; 52 ) and somatic embryogenesis (ERF022; 53 ). Overall, among the novel ROS TFs validated for an oxidative stress function by literature evidence or in our phenotyping assays, the AP2-EREBP (5), NAC (5) and WRKY (5) families are highly represented (Supplemental Table S5).…”