Trifurcate Feed-Forward Regulation of Age-Dependent Cell Death Involving miR164 in Arabidopsis

Abstract

Aging induces gradual yet massive cell death in higher organisms, including annual plants. Even so, the underlying regulatory mechanisms are barely known, despite the long-standing interest in this topic. Here, we demonstrate that ORE1, which is a NAC (NAM, ATAF, and CUC) transcription factor, positively regulates aging-induced cell death in Arabidopsis leaves. ORE1 expression is up-regulated concurrently with leaf aging by EIN2 but is negatively regulated by miR164. miR164 expression gradually decreases with aging through negative regulation by EIN2, which leads to the elaborate up-regulation of ORE1 expression. However, EIN2 still contributes to aging-induced cell death in the absence of ORE1. The trifurcate feed-forward pathway involving ORE1, miR164, and EIN2 provides a highly robust regulation to ensure that aging induces cell death in Arabidopsis leaves.

ABA receptor PYL9 promotes drought resistance and leaf senescence

“…S8C) (8). These NAC transcription factors promote the expression of downstream SAGs, which in turn, control leaf senescence (5)(6)(7)34). The SAGs are involved in transcription regulation, protein modification and degradation, macromolecule degradation, transportation, antioxidation, and autophagy (35).…”

A Genome-Wide Chronological Study of Gene Expression and Two Histone Modifications, H3K4me3 and H3K9ac, during Developmental Leaf Senescence

“…WRKY53 expression is down-regulated by Whirly1 (Miao et al, 2013), which may explain the coincidence of low transcript levels and high levels of H3K4me3 marks. Examples of posttranscriptional regulation mediated by small RNAs have been identified during leaf senescence (Kim et al, 2009a(Kim et al, , 2009bLi et al, 2013b;Thatcher et al, 2015) and may also explain some of the inconsistencies between H3K4me3 marks and gene expression. Senescence associated gene12 (SAG12), a molecular marker for senescence, was up-regulated 3,300-fold between 29 and 57 d (0.022-72.5 RPKM) and showed increased levels of H3K4me3 marks 250 to 650 bp upstream of the TSS but no clear H3K9ac marks (Supplemental Fig.…”

Comprehensive Dissection of Spatiotemporal Metabolic Shifts in Primary, Secondary, and Lipid Metabolism during Developmental Senescence in Arabidopsis

“…Although many SDGs and SAGs have been characterized (Miao et al, 2004;Guo and Gan, 2006;Kim et al, 2009;Balazadeh et al, 2010), there is little information on the distinctive spatiotemporal metabolic changes occurring during the senescence process. In order to study senescenceassociated metabolites and metabolic remobilization during senescence, profiling of metabolites, including pigments, lipids, sugars, amino acids, organic acids, and secondary metabolites (in total, approximately 260 annotated metabolites), was performed using samples obtained from leaves and siliques at different Table S4).…”

“…In addition to the loss of chlorophyll, the transcript abundance of SDGs and SAGs was analyzed to aid in the classification of leaf senescence stages. Two SDGs encoding chlorophyll a/bbinding protein1 (CAB1) and ribulose bisphosphate carboxylase small subunit1A (RBCS1A), as well as three SAGs encoding SAG12 (Cys-type peptidase), SAG21 (AtLEA5; for late embryogenesis abundant-like protein), and senescence-associated protein1 (SEN1; for dark inducible1, DIN1), which are commonly used as leaf senescence marker genes in Arabidopsis, and the three transcription factors WRKY53 (Miao et al, 2004), ANAC029 (Guo and Gan, 2006), and ANAC092 (Kim et al, 2009;Balazadeh et al, 2010), which are known to regulate senescence, were analyzed (Fig. 1,C and D).…”