scholarly journals Local brassinosteroid biosynthesis enables optimal root growth

2020 ◽  
Author(s):  
Nemanja Vukašinović ◽  
Yaowei Wang ◽  
Isabelle Vanhoutte ◽  
Matyáš Fendrych ◽  
Boyu Guo ◽  
...  
Keyword(s):  
Root Growth ◽  
Root Elongation ◽  
Cell Movement ◽  
Elongation Zone ◽  
Long Distance ◽  
Limited Mobility ◽  
Hormone Synthesis ◽  
Spatiotemporal Regulation ◽  
Biosynthetic Machinery ◽  
Root Axis

AbstractBrassinosteroid hormones are indispensable for root growth and they control both cell division and cell elongation through the establishment of an increasing signaling gradient along the longitudinal root axis. Because of their limited mobility, the importance of brassinosteroid distribution for achieving the signaling maximum is largely overlooked. Expression pattern analysis of all known brassinosteroid biosynthetic enzymes revealed that not all cells in the Arabidopsis thaliana root possess full biosynthetic machinery and completion of biosynthesis relies on cell-to-cell movement of the hormone precursors. We demonstrate that brassinosteroid biosynthesis is largely restricted to the root elongation zone where it overlaps with brassinosteroid signaling maxima. Moreover, optimal root growth requires hormone concentrations, low in the meristem and high in the root elongation zone attributable to an increased biosynthesis. Our finding that spatiotemporal regulation of hormone synthesis results in a local hormone accumulation provides a paradigm for hormone-driven organ growth in the absence of long-distance hormone transport in plants.

scholarly journals Apical-root apoplastic acidification affects cell-wall extensibility in wheat under salinity stress

2020 ◽  
Author(s):  
Yang Shao ◽  
Xiaohui Feng ◽  
Hiroki Nakahara ◽  
Muhammad Irshad ◽  
A. Egrinya Eneji ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Salinity Stress ◽  
Root Elongation ◽  
Elongation Zone ◽  
Cell Wall Extensibility ◽  
Cell Wall Loosening ◽  
Dependent Cell ◽  
Wall Loosening ◽  
Wall Extensibility

AbstractPlant salt tolerance is closely associated with a high rate of root growth. Although root growth is governed by cell-wall and apoplastic pH, the relationship between these factors in the root elongation zone under salinity stress remains unclear. Here, we assess apoplastic pH, pH- and expansin-dependent cell-wall extensibility, and expansin expression in the root elongation zone of salt-sensitive (Yongliang-15) and -tolerant (JS-7) cultivars under salinity stress. A six-day 80 mM NaCl treatment significantly reduced apical-root apoplastic pH, from 6.2 to 5.3, in both cultivars. Using a pH-dependent cell-wall extensibility experiment, we found that, under 0 mM NaCl treatment, the optimal pH for cell-wall loosening was 6.0 in the salinity-tolerant cultivar and 4.6 in the salinity-sensitive cultivar. Under 80 mM treatment, a pH of 5.0 mitigated the cell-wall stiffness caused by salinity stress in the salinity-tolerant cultivar, but promoted cell-wall stiffening in the salinity-sensitive cultivar. These changes in pH-dependent cell-wall extensibility are consistent with differences in the root growth of two cultivars under salinity stress. Exogenous expansin application, and expansin expression experiments, we found that salinity stress altered expansin expression, differentially affecting cell-wall extensibility under pH 5.0 and 6.0. TaEXPA7 and TaEXPA8 induced cell-wall loosening at pH 5.0, whereas TaEXPA5 induced cell-wall loosening at pH 6.0. These results elucidate the relationship between expansin and cell-wall extensibility in the root elongation zone, with important implications for enhancing plant growth under salinity stress.

scholarly journals Arabidopsis HB52 mediates the crosstalk between ethylene and auxin signaling pathways by regulating PIN2, WAG1, and WAG2 during primary root elongation

2018 ◽  
Author(s):  
Zi-Qing Miao ◽  
Ping-Xia Zhao ◽  
Jie-Li Mao ◽  
Lin-Hui Yu ◽  
Yang Yuan ◽  
...  
Keyword(s):  
Root Growth ◽  
Signaling Pathways ◽  
Molecular Mechanism ◽  
Root Elongation ◽  
Auxin Transport ◽  
Primary Root ◽  
Auxin Signaling ◽  
Elongation Zone ◽  
Ethylene Signaling ◽  
Physiological Processes

AbstractThe gaseous hormone ethylene participates in many physiological processes of plants. It is well known that ethylene-inhibited root elongation involves basipetal auxin delivery requiring PIN2. However, the molecular mechanism how ethylene regulates PIN2 is not well understood. Here, we report that the ethylene-responsive HD-Zip gene HB52 is involved in ethylene-mediated inhibition of primary root elongation. Using biochemical and genetic analyses, we demonstrated that HB52 is ethylene-responsive and acts immediately downstream of EIN3. HB52 knock-down mutants are insensitive to ethylene in primary root elongation while the overexpression lines have dramatically shortened roots like ethylene treated plants. Moreover, HB52 upregulates PIN2, WAG1, and WAG2 by directly binding to their promoter, leading to an enhanced basipetal auxin delivery to the elongation zone and thus inhibiting root growth. Our work uncovers HB52 as an important crosstalk node between ethylene signaling and auxin transport in root elongation.

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

Genes ◽  
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.

scholarly journals Messenger RNAs Mobile in Salix Matsudana Grafts Were in Association With Plant Rooting

2021 ◽  
Author(s):  
Yin Peng ◽  
Liu Xiao ◽  
Lan Baoliang ◽  
Cui Yu ◽  
Wang Yan ◽  
...  
Keyword(s):  
Root Growth ◽  
Differentially Expressed Genes ◽  
Transcriptome Analysis ◽  
Plant Hormone ◽  
Snp Analysis ◽  
Messenger Rnas ◽  
Long Distance ◽  
Salix Matsudana ◽  
Expression Abundance ◽  
Gc Contents

Abstract Messenger RNAs exchanged between scions and rootstocks of grafted plants seriously affect their traits performance. The study goals were to identify the long-distance mRNA transmission events in grafted willows using a transcriptome analysis and to reveal the possible effects on rooting traits. The results showed that the Salix matsudana variety 9901 has better rooting ability than YJ, which reasonably improved the rooting performance of the heterologous grafts 9901 (scion) / YJ (rootstock). A transcriptome analysis showed that 2,948 differentially expressed genes (DEGs) were present in the rootstock of 9901/YJ grafted plants in comparison with YJ/YJ. Among them, 692 were identified as mRNAs moved from 9901 scion based on a SNP analysis of two parents. They were mostly 1,001–1,500 bp, had 40–45% GC contents, or had expression abundance values less than 10. However, mRNAs over 4,001 bp, having 50–55% GC contents, or having expression abundance values of 10–20 were preferentially transferred. Eight mRNAs subjected to long-distance trafficking were involved in the plant hormone pathways and may significantly promote the root growth of grafted plants. Thus, heterologous grafts of Salix matsudana could efficiently influence plant rooting since of the mRNAs transport from scion to rootstock. Thus, the grafting parents and grafting patterns would be much concerned in the breeding process to gain the expected results in future.

scholarly journals Genome-wide identification and transcriptional analyses of MATE transporter genes in root tips of wild Cicer spp. under aluminium stress

2020 ◽  
Author(s):  
Xia Zhang ◽  
Brayden Weir ◽  
Hongru Wei ◽  
Zhiwei Deng ◽  
Xiaoqi Zhang ◽  
...  
Keyword(s):  
Root Growth ◽  
Root Elongation ◽  
Transcriptional Profiling ◽  
Functional Characterization ◽  
Relative Reduction ◽  
Root Tips ◽  
Al Tolerance ◽  
Genome Wide ◽  
Encoding Genes ◽  
Al Treatment

AbstractChickpea is an economically important legume crop with high nutritional value in human diets. Aluminium-toxicity poses a significant challenge for the yield improvement of this increasingly popular crop in acidic soils. The wild progenitors of chickpea may provide a more diverse gene pool for Al-tolerance in chickpea breeding. However, the genetic basis of Al-tolerance in chickpea and its wild relatives remains largely unknown. Here, we assessed the Al-tolerance of six selected wild Cicer accessions by measuring the root elongation in solution culture under control (0 µM Al3+) and Al-treatment (30 µM Al3+) conditions. Al-treatment significantly reduced the root elongation in all target lines compared to the control condition after 2-day’s growth. However, the relative reduction of root elongation in different lines varied greatly: 3 lines still retained significant root growth under Al-treatment, whilst another 2 lines displayed no root growth at all. We performed genome-wide identification of multidrug and toxic compound extrusion (MATE) encoding genes in the Cicer genome. A total of 56 annotated MATE genes were identified, which divided into 4 major phylogeny groups (G1-4). Four homologues to lupin LaMATE (> 50% aa identity; named CaMATE1-4) were clustered with previously characterised MATEs related to Al-tolerance in various other plants. qRT-PCR showed that CaMATE2 transcription in root tips was significantly up-regulated upon Al-treatment in all target lines, whilst CaMATE1 was up-regulated in all lines except Bari2_074 and Deste_064, which coincided with the lines displaying no root growth under Al-treatment. Transcriptional profiling in five Cicer tissues revealed that CaMATE1 is specifically transcribed in the root tissue, further supporting its role in Al-detoxification in roots. This first identification of MATE-encoding genes associated with Al-tolerance in Cicer paves the ways for future functional characterization of MATE genes in Cicer spp., and to facilitate future design of gene-specific markers for Al-tolerant line selection in chickpea breeding programs.

scholarly journals Lateral Root Priming Synergystically Arises from Root Growth and Auxin Transport Dynamics

2018 ◽  
Author(s):  
Thea van den Berg ◽  
Kirsten H. ten Tusscher
Keyword(s):  
Cell Cycle ◽  
Root Growth ◽  
Lateral Root ◽  
Root Formation ◽  
Growth Dynamics ◽  
Root Tip ◽  
Cycle Duration ◽  
Elongation Zone ◽  
Lateral Root Formation ◽  
Cell Cycle Duration

AbstractThe root system is a major determinant of plant fitness. Its capacity to supply the plant with sufficient water and nutrients strongly depends on root system architecture, which arises from the repeated branching off of lateral roots. A critical first step in lateral root formation is priming, which prepatterns sites competent of forming a lateral root. Priming is characterized by temporal oscillations in auxin, auxin signalling and gene expression in the root meristem, which through growth become transformed into a spatially repetitive pattern of competent sites. Previous studies have demonstrated the importance of auxin synthesis, transport and perception for the amplitude of these oscillations and their chances of producing an actual competent site. Additionally, repeated lateral root cap apoptosis was demonstrated to be strongly correlated with repetitive lateral root priming. Intriguingly, no single mutation has been identified that fully abolishes lateral root formation, and thusfar the mechanism underlying oscillations has remained unknown. In this study, we investigated the impact of auxin reflux loop properties combined with root growth dynamics on priming, using a computational approach. To this end we developed a novel multi-scale root model incorporating a realistic root tip architecture and reflux loop properties as well as root growth dynamics. Excitingly, in this model, repetitive auxin elevations automatically emerge. First, we show that root tip architecture and reflux loop properties result in an auxin loading zone at the start of the elongation zone, with preferential auxin loading in narrow vasculature cells. Second, we demonstrate how meristematic root growth dynamics causes regular alternations in the sizes of cells arriving at the elongation zone, which subsequently become amplified during cell expansion. These cell size differences translate into differences in cellular auxin loading potential. Combined, these properties result in temporal and spatial fluctuations in auxin levels in vasculature and pericycle cells. Our model predicts that temporal priming frequency predominantly depends on cell cycle duration, while cell cycle duration together with meristem size control lateral root spacing.

scholarly journals Root Growth of Avocado is More Sensitive to Salinity than Shoot Growth

2004 ◽  
Vol 129 (2) ◽  
pp. 188-192 ◽  
Author(s):  
N. Bernstein ◽  
A. Meiri ◽  
M. Zilberstaine
Keyword(s):  
Salt Stress ◽  
Root Growth ◽  
Biomass Production ◽  
Root Elongation ◽  
Shoot Growth ◽  
Elongation Rate ◽  
Persea Americana ◽  
Root Growth Inhibition ◽  
Leaf Biomass ◽  
Volumetric Growth

In most crop species, growth of the shoot is more sensitive to salt stress than root growth. Avocado [Persea americana Mill.] is very sensitive to NaCl stress. Even low concentrations of salt (15 mm) inhibit tree growth and decrease productivity. Observations in experimental orchards have suggested that root growth in avocado might be more restricted by salinity than shoot growth. In the present study, we evaluated quantitatively the inhibitory effects of salt stress on growth of the avocado root in comparison to the shoot. Seedling plants of the West-Indian rootstock `Degania 117' were grown in complete nutrient solution containing 1, 5, 15, or 25 mm NaCl. The threshold NaCl concentration causing root and shoot growth reduction occurred between 5 and 15 mm. At all concentrations, root growth was much more sensitive to salinity than shoot growth. A concentration of 15 mm NaCl, which did not affect the rate of leaf emergence on the plant and decreased leaf biomass production only 10%, induced a 43% reduction in the rate of root elongation and decreased root volumetric growth rate by 33%. Under 25 mm NaCl, leaf biomass production, leaf initiation rate and leaf elongation rate were reduced 19.5%, 12%, and 5%, respectively, while root volumetric growth and root elongation rate were reduced 65% and 75%, respectively. This strong root growth inhibition is expected to influence the whole plant and therefore root growth under salinity should be considered as an important criterion for rootstocks' tolerance to NaCl.

scholarly journals Changes in cell ultrastructure and morphology of Arabidopsis thaliana roots after coumarins treatment

2014 ◽  
Vol 70 (3) ◽  
pp. 187-198
Author(s):  
Ewa Kupidłowska
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Root Elongation ◽  
Inhibitory Effect ◽  
Cell Ultrastructure ◽  
Radial Expansion ◽  
Elongation Zone ◽  
Cortical Cells ◽  
Mother Cell Wall

The ultrastructure and morphology of roots treated with coumarin and umbelliferone as well as the reversibility of the coumarins effects caused by exogenous GA, were studied in <em>Arabidopsis thaliana</em>. Both coumarins suppressed root elongation and appreciably stimulated radial expansion of epidermal and cortical cells in the upper part of the meristem and in the elongation zone. The gibberellic acid applied simultaneously with coumarins decreased their inhibitory effect on root elongation and reduced cells swelling.Microscopic observation showed intensive vacuolization of cells and abnormalities in the structure of the Golgi stacks and the nuclear envelope. The detection of active acid phosphatase in the cytosol of swollen cells indicated increased membrane permeability. Significant abnormalities of newly formed cell walls, e.g. the discontinuity of cellulose layer, uncorrect position of walls and the lack of their bonds with the mother cell wall suggest that coumarins affected the cytoskeleton.

Sign in / Sign up

Export Citation Format

Share Document