ORESARA15, a PLATZ transcription factor, mediates leaf growth and senescence in Arabidopsis

Abstract

Plant leaves undergo a series of developmental changes from leaf primordium initiation through growth and maturation to senescence throughout their life span. Although the mechanisms underlying leaf senescence have been intensively elucidated, our knowledge of the interrelationship between early leaf development and senescence is still fragmentary. We isolated the oresara15-1Dominant (ore15-1D) mutant, which had an extended leaf longevity and an enlarged leaf size, from activation-tagged lines of Arabidopsis. Plasmid rescue identified that ORE15 encodes a PLANT A/T-RICH SEQUENCE- AND ZINC-BINDING PROTEIN family transcription factor. Phenotypes of ore15-1D and ore15-2, a loss-of-function mutant, were evaluated through physiological and anatomical analyses. Microarray, quantitative reverse transcription polymerase chain reaction, and chromatin immunoprecipitation as well as genetic analysis were employed to reveal the molecular mechanism of ORE15 in the regulation of leaf growth and senescence. ORE15 enhanced leaf growth by promoting the rate and duration of cell proliferation in the earlier stage and suppressed leaf senescence in the later stage by modulating the GROWTH-REGULATING FACTOR (GRF)/GRF-INTERACTING FACTOR regulatory pathway. Our study highlighted a molecular conjunction through ORE15 between growth and senescence, which are two temporally separate developmental processes during leaf life span.

A Rice Transcription Factor Controls Grain Length through Cell Number

“…Interestingly, GL6 expression in the complementation line is approximately four times higher than in the GLA4, and not significantly different between the wild-type GLA4 and NIL-gl6, although it must be noted that the transcript levels will not necessarily directly correlate with active protein levels, especially in the case of truncated transcripts. There is limited evidence that PLATZ transcription factors may have a role in the promotion of cell division in Arabidopsis (Arabidopsis thaliana) leaves through interaction with the GROWTH REGULATING FACTOR (GRF)/GRF-INTERACTING FACTOR regulatory module (Kim et al, 2018). This module regulates cell growth and proliferation, and it is particularly important in the generation of stem cells for organogenesis (Kim and Tsukaya, 2015).…”

The MYB transcription factor Emission of Methyl Anthranilate 1 stimulates emission of methyl anthranilate from Medicago truncatula hairy roots

“…Together, these findings further support that maize PLATZ proteins may be generally involved in the modulation of RNAPIII‐mediated small non‐coding RNA transcription (Wang et al ., ). Through this action, they may modulate endosperm development and storage reserve filling in maize seeds (Wang et al ., ), leaf growth and senescence in Arabidopsis (Kim et al ., ), or responses to abiotic stresses in cotton ( Gossypium hirsutum ) and Arabidopsis (Zhang et al ., ).…”

“…Here, we demonstrated MtPLATZ1 to be a transcriptional repressor protein in a complex transcriptional network that controls the emission of VOCs from M. truncatula (hairy) roots. Apart from their initial discovery as transcriptional repressors almost two decades ago (Nagano et al, 2001), no studies have been published on plant PLATZ proteins until very recently, with four new studies shedding light on the possible functions of this enigmatic family of transcription factors (Li et al, 2017a;Kim et al, 2018;Wang et al, 2018;Zhang et al, 2018). Originally, the pea (Pisum sativum) PLATZ1 protein was shown to non-specifically bind to A/T-rich sequences in the upstream regions of pea genes and mediate transcriptional repression (Nagano et al, 2001).…”

“…RNAPIII-mediated small non-coding RNA transcription (Wang et al, 2018). Through this action, they may modulate endosperm development and storage reserve filling in maize seeds (Wang et al, 2018), leaf growth and senescence in Arabidopsis (Kim et al, 2018), or responses to abiotic stresses in cotton (Gossypium hirsutum) and Arabidopsis (Zhang et al, 2018). In addition to the (indirect) transcriptional silencing of MtAAMT1, MtPLATZ1 also represses the expression of EMA1; we postulate that this is either by direct binding of the EMA1 promoter or through activation of the expression of a repressing non-coding RNA, given our own findings or the recently reported roles of PLATZ proteins (Figure 7).…”

ORESARA15 Acts Synergistically with ANGUSTIFOLIA3 and Separately from AINTEGUMENTA to Promote Cell Proliferation during Leaf Growth

“…TCP4 affects cell proliferation regulation via the induction of miRNA396, which represses the GRF family, and by direct connection with KIP-RELATED PROTEIN 1 (KRP1) which terminates the cell cycle and induces the transition from mitotic cell cycle to the endocycle causing an increase in DNA ploidy by directly interacting with cell cycle genes [2,24]. Previously, we isolated and characterized ORESARA 15 (ORE15) encoding a plant A/T-rich sequence-and zinc-binding protein (PLATZ) family transcription factor and determined that ORE15 enhances leaf growth by promoting the rate and duration of cell proliferation in its early stage and suppresses leaf senescence in its late stage by modulating the miRNA396-GRF-GIF regulatory pathway [25]. It has been proposed that ORE15 may act as a transcriptional activator since it positively regulates the expression of GRF1 and GRF4 through direct binding to their promoters [25].…”