Ammonium Inhibits Primary Root Growth by Reducing the Length of Meristem and Elongation Zone and Decreasing Elemental Expansion Rate in the Root Apex in Arabidopsis thaliana

Abstract Nitrate can act as a potent signal to control growth and development in plants. In this study, we show that nitrate is able to stimulate primary root growth via increased meristem activity and cytokinin signaling. Cytokinin perception and biosynthesis mutants displayed shorter roots as compared with wild-type plants when grown with nitrate as the only nitrogen source. Histological analysis of the root tip revealed decreased cell division and elongation in the cytokinin receptor double mutant ahk2/ahk4 as compared with wild-type plants under a sufficient nitrate regime. Interestingly, a nitrate-dependent root growth arrest was observed between days 5 and 6 after sowing. Wild-type plants were able to recover from this growth arrest, while cytokinin signaling or biosynthesis mutants were not. Transcriptome analysis revealed significant changes in gene expression after, but not before, this transition in contrasting genotypes and nitrate regimes. We identified genes involved in both cell division and elongation as potentially important for primary root growth in response to nitrate. Our results provide evidence linking nitrate and cytokinin signaling for the control of primary root growth in Arabidopsis thaliana.

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Ethylene mediates dichromate-induced inhibition of primary root growth by altering AUX1 expression and auxin accumulation in Arabidopsis thaliana

Plant Cell & Environment ◽

10.1111/pce.13174 ◽

2018 ◽

Vol 41 (6) ◽

pp. 1453-1467 ◽

Cited By ~ 15

Author(s):

Abdul Wakeel ◽

Imran Ali ◽

Sakila Upreti ◽

Azizullah Azizullah ◽

Bohan Liu ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Root Growth ◽

Primary Root ◽

Primary Root Growth ◽

Auxin Accumulation

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Arabidopsis thaliana GH3.9 influences primary root growth

Planta ◽

10.1007/s00425-006-0462-2 ◽

2007 ◽

Vol 226 (1) ◽

pp. 21-34 ◽

Cited By ~ 48

Author(s):

Sadaf Khan ◽

Julie M. Stone

Keyword(s):

Arabidopsis Thaliana ◽

Root Growth ◽

Primary Root ◽

Primary Root Growth

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TPST is involved in fructose regulation of primary root growth in Arabidopsis thaliana

Plant Molecular Biology ◽

10.1007/s11103-020-01006-x ◽

2020 ◽

Vol 103 (4-5) ◽

pp. 511-525

Author(s):

Yingli Zhong ◽

Jiyong Xie ◽

Suzhen Wen ◽

Wenwu Wu ◽

Li Tan ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Root Growth ◽

Primary Root ◽

Primary Root Growth

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Primary root growth in Arabidopsis thaliana is inhibited by the miR159 mediated repression of MYB33 , MYB65 and MYB101

Plant Science ◽

10.1016/j.plantsci.2017.06.008 ◽

2017 ◽

Vol 262 ◽

pp. 182-189 ◽

Cited By ~ 17

Author(s):

Tao Xue ◽

Zhenhua Liu ◽

Xuehuan Dai ◽

Fengning Xiang

Keyword(s):

Arabidopsis Thaliana ◽

Root Growth ◽

Primary Root ◽

Primary Root Growth

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Bacillus megaterium Rhizobacteria Promote Growth and Alter Root-System Architecture Through an Auxin- and Ethylene-Independent Signaling Mechanism in Arabidopsis thaliana

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-2-0207 ◽

2007 ◽

Vol 20 (2) ◽

pp. 207-217 ◽

Cited By ~ 146

Author(s):

José López-Bucio ◽

Juan Carlos Campos-Cuevas ◽

Erasto Hernández-Calderón ◽

Crisanto Velásquez-Becerra ◽

Rodolfo Farías-Rodríguez ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Root Growth ◽

Root Hair ◽

Lateral Root ◽

Root Formation ◽

Growth Promotion ◽

Primary Root ◽

Root System Architecture ◽

Ethylene Signaling ◽

Primary Root Growth

Soil microorganisms are critical players in plant-soil interactions at the rhizosphere. We have identified a Bacillus megaterium strain that promoted growth and development of bean (Phaseolus vulgaris) and Arabidopsis thaliana plants. We used Arabidopsis thaliana as a model to characterize the effects of inoculation with B. megaterium on plant-growth promotion and postembryonic root development. B. megaterium inoculation caused an inhibition in primary-root growth followed by an increase in lateral-root number, lateral-root growth, and root-hair length. Detailed cellular analyses revealed that primary root-growth inhibition was caused both by a reduction in cell elongation and by reduction of cell proliferation in the root meristem. To study the contribution of auxin and ethylene signaling pathways in the alterations in root-system architecture elicited by B. megaterium, a suite of plant hormone mutants of Arabidopsis, including aux1-7, axr4-1, eir1, etr1, ein2, and rhd6, defective in either auxin or ethylene signaling, were evaluated for their responses to inoculation with this bacteria. When inoculated, all mutant lines tested showed increased biomass production. Moreover, aux1-7 and eir1, which sustain limited root-hair and lateral-root formation when grown in uninoculated medium, were found to increase the number of lateral roots and to develop long root hairs when inoculated with B. megaterium. The ethylene-signaling mutants etr1 and ein2 showed an induction in lateral-root formation and root-hair growth in response to bacterial inoculation. Taken together, our results suggest that plant-growth promotion and root-architectural alterations by B. megaterium may involve auxin- and-ethylene independent mechanisms.

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Long-distance blue light signalling regulates phosphate deficiency-induced primary root growth inhibition

Molecular Plant ◽

10.1016/j.molp.2021.06.002 ◽

2021 ◽

Author(s):

Yi-Qun Gao ◽

Ling-Hua Bu ◽

Mei-Ling Han ◽

Ya-Ling Wang ◽

Zong-Yun Li ◽

...

Keyword(s):

Root Growth ◽

Growth Inhibition ◽

Blue Light ◽

Primary Root ◽

Phosphate Deficiency ◽

Root Growth Inhibition ◽

Long Distance ◽

Light Signalling ◽

Primary Root Growth

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The Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 Gene Is Involved in Anisotropic Root Growth during Osmotic Stress Adaptation

Genes ◽

10.3390/genes12020236 ◽

2021 ◽

Vol 12 (2) ◽

pp. 236

Author(s):

María Belén Cuadrado-Pedetti ◽

Inés Rauschert ◽

María Martha Sainz ◽

Vítor Amorim-Silva ◽

Miguel Angel Botella ◽

...

Keyword(s):

Osmotic Stress ◽

Root Growth ◽

Cell Walls ◽

Primary Root ◽

Stress Adaptation ◽

Elongation Zone ◽

Cortical Cells ◽

Force Microscopy ◽

Atomic Force ◽

The Mean

Mutations in the Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 (TTL1) gene cause reduced tolerance to osmotic stress evidenced by an arrest in root growth and root swelling, which makes it an interesting model to explore how root growth is controlled under stress conditions. We found that osmotic stress reduced the growth rate of the primary root by inhibiting the cell elongation in the elongation zone followed by a reduction in the number of cortical cells in the proximal meristem. We then studied the stiffness of epidermal cell walls in the root elongation zone of ttl1 mutants under osmotic stress using atomic force microscopy. In plants grown in control conditions, the mean apparent elastic modulus was 448% higher for live Col-0 cell walls than for ttl1 (88.1 ± 2.8 vs. 16.08 ± 6.9 kPa). Seven days of osmotic stress caused an increase in the stiffness in the cell wall of the cells from the elongation zone of 87% and 84% for Col-0 and ttl1, respectively. These findings suggest that TTL1 may play a role controlling cell expansion orientation during root growth, necessary for osmotic stress adaptation.

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