scholarly journals Activation of 1-Aminocyclopropane-1-Carboxylic Acid Synthases Sets Stomatal Density and Clustered Ratio on Leaf Epidermis of Arabidopsis in Response to Drought

2021 ◽  
Vol 12 ◽  
Author(s):  
Ming-zhu Jia ◽  
Ling-yun Liu ◽  
Chen Geng ◽  
Jing Jiang
Keyword(s):  
Transcription Factor ◽  
Stomatal Density ◽  
Acc Synthase ◽  
Drought Response ◽  
Leaf Epidermis ◽  
Stomatal Development ◽  
Growth And Survival ◽  
Drought Conditions ◽  
Moderate Drought

The adjustment of stomatal density and clustered ratio on the epidermis is the important strategy for plants to respond to drought, because the stoma-based water loss is directly related to plant growth and survival under drought conditions. But the relevant adjustment mechanism still needs to be explored. 1-Aminocyclopropane-1-carboxylate (ACC) is disclosed to promote stomatal development, while in vivo ACC levels depend on activation of ACC synthase (ACS) family members. Based on the findings of ACS expression involving in drought response and several ACS activity inhibitors reducing stomatal density and cluster in drought response, here we examined how ACS activation is involved in the establishment of stomatal density and cluster on the epidermis under drought conditions. Preliminary data indicated that activation of ACS2 and/or ACS6 (ACS2/6) increased stomatal density and clustered ratio on the Arabidopsis leaf epidermis by accumulating ACC under moderate drought, and raised the survival risk of seedlings under escalated drought. Further exploration indicated that, in Arabidopsis seedlings stressed by drought, the transcription factor SPEECHLESS (SPCH), the initiator of stomatal development, activates ACS2/6 expression and ACC production; and that ACC accumulation induces Ca2+ deficiency in stomatal lineage; this deficiency inactivates a subtilisin-like protease STOMATAL DENSITY AND DISTRIBUTION 1 (SDD1) by stabilizing the inhibition of the transcription factor GT-2 Like 1 (GTL1) on SDD1 expression, resulting in an increases of stomatal density and cluster ratio on the leaf epidermis. This work provides a novel evidence that ACS2/6 activation plays a key role in the establishment of stomatal density and cluster on the leaf epidermis of Arabidopsis in response to drought.

scholarly journals Activation of ACC synthase 2/6 increases stomatal density and cluster on the Arabidopsis leaf epidermis during drought

2021 ◽  
Author(s):  
Ming-zhu Jia ◽  
Ling-yun Liu ◽  
Chen Geng ◽  
Chun-peng Song ◽  
Jing Jiang
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Stomatal Density ◽  
Acc Synthase ◽  
Individual Development ◽  
Leaf Epidermis ◽  
Stomatal Development ◽  
Drought Conditions ◽  
The Relationship ◽  
Stomatal Lineage

AbstractIt is known that the transcription factor SPEECHLESS (SPCH) drives entry of epidermal cells into stomatal lineage, and that the activation of subtilisin-like protease SDD1 reduces stomatal density and cluster on the epidermis. However, there is still a big gap in our understanding of the relationship between stomatal development and the establishment of stomatal density and pattern, especially during drought. Interestingly, 1-aminocyclopropane-1-carboxylic acid (ACC) not only promotes stomatal development, but also is involved in the establishment of stomatal density and pattern. ACC generation comes from the activity of ACC synthase (ACS), while ACS activity could be mediated by drought. This work showed that the Arabidopsis SPCH activated ACS2/6 expression and ACC-dependent stomatal generation with an increase of stomatal density and cluster under drought conditions; and the possible mechanisms were that ACC-induced Ca2+ shortage in stomatal lineage reduced the inhibition of the transcription factor GT-2 Like 1 (GTL1) on SDD1 expression. These suggest that ACS2/6-dependent ACC accumulation integrated stomatal development with the establishment of stomatal density and pattern by mediating Ca2+ levels in stomatal lineage cells on the leaf epidermis, and this integration is directly related to the growth or survival of plants under escalated drought stress.HighlightACC synthase ACS2/6 activation integrated stomatal individual development with space setting between stomata by mediating Ca2+ levels in stomatal lineage on the leaf epidermis in response to drought.

The transcription factor ZmNAC49 reduces stomatal density and improves drought tolerance in maize

2020 ◽  
Author(s):  
Yang Xiang ◽  
Xiujuan Sun ◽  
Xiangli Bian ◽  
Tianhui Wei ◽  
Tong Han ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Stomatal Conductance ◽  
Drought Tolerance ◽  
Transpiration Rate ◽  
Transcriptional Activation ◽  
Stomatal Density ◽  
Stomatal Development ◽  
Expression Of Genes ◽  
Growth Development

Abstract Drought stress severely limits the growth, development, and productivity of crops, and therefore understanding the mechanisms by which plants respond to drought is crucial. In this study, we cloned a maize NAC transcription factor, ZmNAC49, and identified its function in response to drought stress. We found that ZmNAC49 is localized in the nucleus and has transcriptional activation activity. ZmNAC49 expression is rapidly and strongly induced by drought stress, and overexpression enhances stress tolerance in maize. Overexpression also significant decreases the transpiration rate, stomatal conductance, and stomatal density in maize. Detailed study showed that ZmNAC49 overexpression affects the expression of genes related to stomatal development, namely ZmTMM, ZmSDD1, ZmMUTE, and ZmFAMA. In addition, we found that ZmNAC49 can directly bind to the promoter of ZmMUTE and suppress its expression. Taken together, our results show that the transcription factor ZmNAC49 represses ZmMUTE expression, reduces stomatal density, and thereby enhances drought tolerance in maize.

scholarly journals The PI3K pathway drives the maturation of mast cells via microphthalmia transcription factor

Blood ◽  
2011 ◽  
Vol 118 (13) ◽  
pp. 3459-3469 ◽  
Author(s):  
Peilin Ma ◽  
Raghuveer Singh Mali ◽  
Veerendra Munugalavadla ◽  
Subha Krishnan ◽  
Baskar Ramdas ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mast Cells ◽  
Pi3k Pathway ◽  
Regulatory Subunit ◽  
Growth And Survival ◽  
Src Homology 3 ◽  
Pi3k Activation ◽  
Src Homology ◽  
Microphthalmia Transcription Factor

Abstract Mast cell maturation is poorly understood. We show that enhanced PI3K activation results in accelerated maturation of mast cells by inducing the expression of microphthalmia transcription factor (Mitf). Conversely, loss of PI3K activation reduces the maturation of mast cells by inhibiting the activation of AKT, leading to reduced Mitf but enhanced Gata-2 expression and accumulation of Gr1+Mac1+ myeloid cells as opposed to mast cells. Consistently, overexpression of Mitf accelerates the maturation of mast cells, whereas Gata-2 overexpression mimics the loss of the PI3K phenotype. Expressing the full-length or the src homology 3– or BCR homology domain–deleted or shorter splice variant of the p85α regulatory subunit of PI3K or activated AKT or Mitf in p85α-deficient cells restores the maturation but not growth. Although deficiency of both SHIP and p85α rescues the maturation of SHIP−/− and p85α−/− mast cells and expression of Mitf; in vivo, mast cells are rescued in some, but not all tissues, due in part to defective KIT signaling, which is dependent on an intact src homology 3 and BCR homology domain of p85α. Thus, p85α-induced maturation, and growth and survival signals, in mast cells can be uncoupled.

scholarly journals The USP28-ΔNp63 axis is a vulnerability of squamous tumours

2019 ◽  
Author(s):  
Cristian Prieto-Garcia ◽  
Oliver Hartmann ◽  
Michaela Reissland ◽  
Fabian Braun ◽  
Thomas Fischer ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Therapeutic Strategy ◽  
Ubiquitin Proteasome System ◽  
Lung Tumour ◽  
Protein Abundance ◽  
Growth And Survival ◽  
Murine Lung ◽  
Ubiquitin Proteasome

AbstractThe transcription factor ΔNp63 is a master regulator that establishes epithelial cell identity and is essential for the survival of SCC of lung, head and neck, oesophagus, cervix and skin. Here, we report that the deubiquitylase USP28 stabilizes ΔNp63 protein and maintains elevated ΔNP63 levels in SCC by counteracting its proteasome-mediated degradation. Interference with USP28 activity by genetic means abolishes the transcriptional identity of SCC cells and suppresses growth and survival of human SCC cells. CRISPR/Cas9-engineered mouse models establish that both induction and maintenance of lung SCC strictly depend on endogenous USP28. Targeting ΔNp63 protein abundance in SCC via inhibition of USP28 therefore is a feasible strategy for the treatment of SCC tumours.SignificanceSCC depend on ΔNp63, and its protein abundance is tightly controlled by the ubiquitin proteasome system. Here, we demonstrate the dependence of SCC on USP28 for various human SCC in vitro and in vivo using murine lung tumour models. As inhibitors for deubiquitylases become available, targeting USP28 is a promising therapeutic strategy.

scholarly journals Misregulation of MYB16 causes stomatal cluster formation by disrupting polarity in asymmetric cell division

2021 ◽  
Author(s):  
Shao-Li Yang ◽  
Ngan Tran ◽  
Meng-Ying Tsai ◽  
Chin-Min Kimmy Ho
Keyword(s):  
Transcription Factor ◽  
Cell Division ◽  
Asymmetric Cell Division ◽  
Stomatal Density ◽  
Ectopic Expression ◽  
Water Evaporation ◽  
Stomatal Development ◽  
Leaf Morphogenesis ◽  
Stomatal Patterning ◽  
Stomatal Lineage

Stomata and leaf cuticle regulate water evaporation from the plant body and balance the trade-off between photosynthesis and water loss. We identified MYB16, a key transcription factor controlling cutin biosynthesis, from previous stomatal lineage ground cell (SLGC)-enriched transcriptome study. The preferential localization of MYB16 in SLGCs but not meristemoids suggests a link between cutin synthesis and stomatal development. Here, we showed that downregulation of MYB16 in meristemoids was directly mediated by the stomatal master transcription factor, SPEECHLESS (SPCH). The suppression of MYB16 before asymmetric division was crucial for stomatal patterning because overexpression or ectopic expression of MYB16 in meristemoids increased impermeability and elevated stomatal density and clusters. The aberrant pattern of stomata was due to reduced and disrupted establishment of polarity during asymmetric cell division. Manipulating polarity by growing seedlings on hard agar rescued stomatal clusters and polarity defects in MYB16 ectopic lines. By expressing a cutinase in MYB16 ectopic lines, stomatal clustering was reduced, which suggests that the ectopic accumulation of cuticle affects the polarity in asymmetrically dividing cells and causes clustered stomata. Taken together, inhibiting MYB16 expression by SPCH in early stomatal lineage is required to correctly place the polarity complex for proper stomatal patterning during leaf morphogenesis.

Subnuclear compartmentalization of sequence-specific transcription factors and regulation of eukaryotic gene expression

2005 ◽  
Vol 83 (4) ◽  
pp. 535-547 ◽  
Author(s):  
Gareth N Corry ◽  
D Alan Underhill
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Current Knowledge ◽  
Nuclear Architecture ◽  
Subnuclear Localization ◽  
Modular Structures

To date, the majority of the research regarding eukaryotic transcription factors has focused on characterizing their function primarily through in vitro methods. These studies have revealed that transcription factors are essentially modular structures, containing separate regions that participate in such activities as DNA binding, protein–protein interaction, and transcriptional activation or repression. To fully comprehend the behavior of a given transcription factor, however, these domains must be analyzed in the context of the entire protein, and in certain cases the context of a multiprotein complex. Furthermore, it must be appreciated that transcription factors function in the nucleus, where they must contend with a variety of factors, including the nuclear architecture, chromatin domains, chromosome territories, and cell-cycle-associated processes. Recent examinations of transcription factors in the nucleus have clarified the behavior of these proteins in vivo and have increased our understanding of how gene expression is regulated in eukaryotes. Here, we review the current knowledge regarding sequence-specific transcription factor compartmentalization within the nucleus and discuss its impact on the regulation of such processes as activation or repression of gene expression and interaction with coregulatory factors.Key words: transcription, subnuclear localization, chromatin, gene expression, nuclear architecture.

scholarly journals Overexpression of MdATG8i improves water use efficiency in transgenic apple by modulating photosynthesis, osmotic balance, and autophagic activity under moderate water deficit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Jia ◽  
Ke Mao ◽  
Ping Wang ◽  
Yu Wang ◽  
Xumei Jia ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Critical Role ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Use Efficiency ◽  
Autophagic Activity

AbstractWater deficit is one of the major limiting factors for apple (Malus domestica) production on the Loess Plateau, a major apple cultivation area in China. The identification of genes related to the regulation of water use efficiency (WUE) is a crucial aspect of crop breeding programs. As a conserved degradation and recycling mechanism in eukaryotes, autophagy has been reported to participate in various stress responses. However, the relationship between autophagy and WUE regulation has not been explored. We have shown that a crucial autophagy protein in apple, MdATG8i, plays a role in improving salt tolerance. Here, we explored its biological function in response to long-term moderate drought stress. The results showed that MdATG8i-overexpressing (MdATG8i-OE) apple plants exhibited higher WUE than wild-type (WT) plants under long-term moderate drought conditions. Plant WUE can be increased by improving photosynthetic efficiency. Osmoregulation plays a critical role in plant stress resistance and adaptation. Under long-term drought conditions, the photosynthetic capacity and accumulation of sugar and amino acids were higher in MdATG8i-OE plants than in WT plants. The increased photosynthetic capacity in the OE plants could be attributed to their ability to maintain optimal stomatal aperture, organized chloroplasts, and strong antioxidant activity. MdATG8i overexpression also promoted autophagic activity, which was likely related to the changes described above. In summary, our results demonstrate that MdATG8i-OE apple lines exhibited higher WUE than WT under long-term moderate drought conditions because they maintained robust photosynthesis, effective osmotic adjustment processes, and strong autophagic activity.

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