Optical Flow Based Arabidopsis Thaliana Root Meristem Cell Division Detection

During moderate severity drought and low water potential (Ψw) stress, poorly understood signaling mechanisms restrict both meristem cell division and subsequent cell expansion. We found that the Clade E Growth-Regulating 2 (EGR2) protein phosphatase and Microtubule Associated Stress Protein 1 (MASP1) differed in their stoichiometry of expression across the root meristem and had opposing effects on root meristem activity at low Ψw. Ectopic MASP1 or EGR expression increased or decreased, respectively, root meristem size and root elongation during low Ψw stress. This, along with the ability of phosphomimic MASP1 to overcome EGR suppression of root meristem size and observation that ectopic EGR expression had no effect on unstressed plants, indicated that during low Ψw EGR activation and attenuation of MASP1 phosphorylation in their overlapping zone of expression determines root meristem size and activity. Ectopic EGR expression also decreased root cell size at low Ψw. Conversely, both the egr1-1egr2-1 and egr1-1egr2-1masp1-1 mutants had similarly increased root cell size; but, only egr1-1egr2-1 had increased cell division. These observations demonstrated that EGRs affect meristem activity via MASP1 but affect cell expansion via other mechanisms. Interestingly, EGR2 was highly expressed in the root cortex, a cell type important for growth regulation and environmental response.

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Nitrogen Deficiency-Induced Decrease in Cytokinins Content Promotes Rice Seminal Root Growth by Promoting Root Meristem Cell Proliferation and Cell Elongation

Cells ◽

10.3390/cells9040916 ◽

2020 ◽

Vol 9 (4) ◽

pp. 916

Author(s):

Qi Wang ◽

Yanchun Zhu ◽

Xiao Zou ◽

Fengfeng Li ◽

Jialiang Zhang ◽

...

Keyword(s):

Cell Proliferation ◽

Root Growth ◽

Cell Elongation ◽

Developmental Plasticity ◽

Root Meristem ◽

Seminal Root ◽

Down Regulation ◽

Meristem Cell ◽

Root Meristem Cell ◽

N Deficiency

Rice (Oryza sativa L.) seedlings grown under nitrogen (N) deficiency conditions show a foraging response characterized by increased root length. However, the mechanism underlying this developmental plasticity is still poorly understood. In this study, the mechanism by which N deficiency influences rice seminal root growth was investigated. The results demonstrated that compared with the control (1 mM N) treatment, N deficiency treatments strongly promoted seminal root growth. However, the N deficiency-induced growth was negated by the application of zeatin, which is a type of cytokinin (CK). Moreover, the promotion of rice seminal root growth was correlated with a decrease in CK content, which was due to the N deficiency-mediated inhibition of CK biosynthesis through the down-regulation of CK biosynthesis genes and an enhancement of CK degradation through the up-regulation of CK degradation genes. In addition, the N deficiency-induced decrease in CK content not only enhanced the root meristem cell proliferation rate by increasing the meristem cell number via the down-regulation of OsIAA3 and up-regulation of root-expressed OsPLTs, but also promoted root cell elongation by up-regulating cell elongation-related genes, including root-specific OsXTHs and OsEXPs. Taken together, our data suggest that an N deficiency-induced decrease in CK content promotes the seminal root growth of rice seedlings by promoting root meristem cell proliferation and cell elongation.

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Faculty Opinions recommendation of Plant-Specific Histone Deacetylases HDT1/2 Regulate GIBBERELLIN 2-OXIDASE2 Expression to Control Arabidopsis Root Meristem Cell Number.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.730362819.793543825 ◽

2018 ◽

Author(s):

Christiaan van der Schoot

Keyword(s):

Histone Deacetylases ◽

Root Meristem ◽

Cell Number ◽

Meristem Cell ◽

Arabidopsis Root ◽

Root Meristem Cell

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Nickel effect on root-meristem cell division in Plantago lanceolata (Plantaginaceae) seedlings

Australian Journal of Botany ◽

10.1071/bt17054 ◽

2017 ◽

Vol 65 (5) ◽

pp. 446 ◽

Cited By ~ 3

Author(s):

Dolja Pavlova

Keyword(s):

Cell Division ◽

Mitotic Index ◽

Root Meristem ◽

Plantago Lanceolata ◽

Nuclear Material ◽

Root Tip ◽

Dependent Manner ◽

Meristem Cell ◽

Anaphase Bridges ◽

Tip Cells

The toxic effect of nickel (Ni) on cell division on root-meristem cells in seedlings of Plantago lanceolata L. was studied and compared. Seed material was collected from serpentine and non-serpentine populations of the species distributed in the Rhodope Mountains, Bulgaria. The root-tip meristem cells of germinated seeds were treated with different solutions of 0.01, 0.025, 0.05, 0.1 mM Ni as NiSO4 6H2O with distilled water for 24 h and 48 h respectively. The mitotic index decreased when Ni concentrations and exposure time increased in both type of samples. Significant differences in the mitotic indexes were found between the controls and the roots treated with Ni. The mitotic index was higher in root-meristem cells of serpentine seedlings. C-mitosis, anaphase bridges, chromosome stickiness, laggards and extrusion of nuclear material into the cytoplasm were observed in the root-tip cells treated with Ni. The percentage of aberrations generally increased in a concentration- and time-dependent manner. The percentage of the extruded nuclei was higher in cells treated with 0.05 and 0.1 mM Ni. It can be concluded that P. lanceolata seedlings on serpentine can tolerate higher Ni concentrations than can non-serpentine seedlings.

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