The action of gravity in agravitropic Zea primary roots: Effect of gravistimulation on the extracellular free-Ca2+ content in the 1-mm apical root tip in the dark

ABSTRACTOrgan morphologies are diverse but also conserved under shared developmental constraints among species. Any geometrical similarities in the shape behind diversity and the underlying developmental constraints remain unclear. Plant root tip outlines commonly exhibit a dome shape, which likely performs physiological functions, despite the diversity in size and cellular organization among distinct root classes and/or species. We carried out morphometric analysis of the primary roots of ten angiosperm species and of the lateral roots (LRs) of Arabidopsis, and found that each root outline was isometrically scaled onto a parameter-free catenary curve, a stable structure adopted for arch bridges. Using the physical model for bridges, we analogized that localized and spatially uniform occurrence of oriented cell division and expansion force the LR primordia (LRP) tip to form a catenary curve. These growth rules for the catenary curve were verified by tissue growth simulation of developing LRP development based on time-lapse imaging. Consistently, LRP outlines of mutants compromised in these rules were found to deviate from catenary curves. Our analyses demonstrate that physics-inspired growth rules constrain plant root tips to form isometrically scalable catenary curves.

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TheArabidopsisNRT1/PTR FAMILY protein NPF7.3/NRT1.5 is an indole-3-butyric acid transporter involved in root gravitropism

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2013305117 ◽

2020 ◽

Vol 117 (49) ◽

pp. 31500-31509

Author(s):

Shunsuke Watanabe ◽

Naoki Takahashi ◽

Yuri Kanno ◽

Hiromi Suzuki ◽

Yuki Aoi ◽

...

Keyword(s):

Butyric Acid ◽

Peptide Transporter ◽

Root Tip ◽

Loss Of Function ◽

Primary Roots ◽

Transporter Family ◽

Family Protein ◽

Protein Functions ◽

Root Gravitropism ◽

Root Tissues

Active membrane transport of plant hormones and their related compounds is an essential process that determines the distribution of the compounds within plant tissues and, hence, regulates various physiological events. Here, we report that theArabidopsisNITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY 7.3 (NPF7.3) protein functions as a transporter of indole-3-butyric acid (IBA), a precursor of the major endogenous auxin indole-3-acetic acid (IAA). When expressed in yeast, NPF7.3 mediated cellular IBA uptake. Loss-of-functionnpf7.3mutants showed defective root gravitropism with reduced IBA levels and auxin responses. Nevertheless, the phenotype was restored by exogenous application of IAA but not by IBA treatment.NPF7.3was expressed in pericycle cells and the root tip region including root cap cells of primary roots where the IBA-to-IAA conversion occurs. Our findings indicate that NPF7.3-mediated IBA uptake into specific cells is required for the generation of appropriate auxin gradients within root tissues.

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Observations of the Golgi Apparatus in Pisum Primary Roots

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100099817 ◽

1968 ◽

Vol 26 ◽

pp. 14-15

Author(s):

Gordon C. Spink

Keyword(s):

Cell Wall ◽

Plasma Membrane ◽

Pisum Sativum ◽

Golgi Apparatus ◽

Common Garden ◽

Root Tip ◽

Garden Pea ◽

Wall Area ◽

Primary Roots ◽

Columella Cells

It is known that the product of the Golgi apparatus vesicles is deposited at and localized in the cell wall. This is accomplished by the formation of the hypertrophied dictyosomes and the subsequent movement of these vesicles to the plasma membrane (Fig. 1). After fusion with the plasma membrane, the secreted material is released into the cell wall area and, in some plants under appropriate conditions, moves outward through the cell wall and appears as a droplet on the root tip.In primary roots of Pisum sativum, var. Alaska (common garden pea) the Golgi apparatus vesicle product accumulates between the plasma membrane and the cell wall, particularly in those cells at the extreme tip of the root. These cells are formed at the acropetal end of the columella cells.

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Cytological and Molecular Characterization of Quantitative Trait Locus qRfg1, Which Confers Resistance to Gibberella Stalk Rot in Maize

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-06-13-0161-r ◽

2013 ◽

Vol 26 (12) ◽

pp. 1417-1428 ◽

Cited By ~ 19

Author(s):

Jianrong Ye ◽

Yanling Guo ◽

Dongfeng Zhang ◽

Nan Zhang ◽

Chao Wang ◽

...

Keyword(s):

Molecular Mechanisms ◽

Microscopic Analysis ◽

Hyphal Growth ◽

Maize Root ◽

Root Tip ◽

Basal Resistance ◽

Stalk Rot ◽

Primary Roots ◽

Tremendous Progress ◽

Trait Locus

Tremendous progress has been made recently in understanding plant response to Fusarium graminearum infection. Here, the cytological aspect and molecular mechanism of maize defense to F. graminearum infection were characterized using a pair of near-isogenic lines (NIL), the resistant and the susceptible NIL. F. graminearum primarily penetrated the maize root tip and no penetration structure was found. The fungal biomass within the root correlated well with root-disease severity. Following inoculation, R-NIL and S-NIL plants significantly differed in percentage of diseased primary roots. In R-NIL roots, a fraction of exodermal cells collapsed to form cavities, and hyphae were confined to the outer exodermal cells. However, most exodermal cells shrank and turned brown, and fungi colonized the entire S-NIL root. In the R-NIL roots, the exodermal cells exhibited plasmolysis and atropous hyphal growth whereas, in the exodermal cells of the S-NIL roots, severe cellular degradation and membrane-coated, lushly grown hyphae were found. Transcriptome sequencing revealed comprehensive transcription reprogramming, reinforcement of a complex defense network, to enhance the systemic and basal resistance. This study reports a detailed microscopic analysis of F. graminearum infection on maize root, and provides insights into the molecular mechanisms underlying maize resistance to the pathogen.

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The Arabidopsis NRT1/PTR FAMILY Protein NPF7.3/NRT1.5 is an Indole-3-butyric Acid Transporter Involved in Root Gravitropism

10.1101/2020.06.04.131797 ◽

2020 ◽

Author(s):

Shunsuke Watanabe ◽

Naoki Takahashi ◽

Yuri Kanno ◽

Hiromi Suzuki ◽

Yuki Aoi ◽

...

Keyword(s):

Butyric Acid ◽

Peptide Transporter ◽

Root Tip ◽

Loss Of Function ◽

Primary Roots ◽

Transporter Family ◽

Family Protein ◽

Protein Functions ◽

Root Gravitropism ◽

Root Tissues

AbstractActive membrane transport of plant hormones and their related compounds is an essential process that determines the distribution of the compounds within plant tissues and, hence, regulates various physiological events. Here, we report that the Arabidopsis NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY 7.3 (NPF7.3) protein functions as a transporter of indole-3-butyric acid (IBA), a precursor of the major endogenous auxin indole-3-acetic acid (IAA). When expressed in yeast, NPF7.3 mediated cellular IBA uptake. Loss-of-function npf7.3 mutants showed defective root gravitropism with reduced IBA levels and auxin responses. Nevertheless, the phenotype was restored by exogenous application of IAA but not by IBA treatment. NPF7.3 was expressed in pericycle cells and the root tip region including root cap cells of primary roots where the IBA-to-IAA conversion occurs. Our findings indicate that NPF7.3-mediated IBA uptake into specific cells is required for the generation of appropriate auxin gradients within root tissues.

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Excised root exudation—a standing-gradient osmotic flow

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1970.0004 ◽

1970 ◽

Vol 174 (1037) ◽

pp. 445-458 ◽

Cited By ~ 39

Keyword(s):

Zea Mays ◽

Flow Model ◽

Root Exudation ◽

Water Flux ◽

Salt Flux ◽

Root Tip ◽

Root Pressure ◽

Osmotic Flow ◽

Osmotic Permeability ◽

Primary Roots

It has been demonstrated that root pressure exudation from excised primary roots of Zea mays is adequately described by a standing gradient osmotic flow model. The differential equations set out by Diamond & Bossart (1967) to describe isotonic water transport across animal epithelia have been modified to render them more appropriate to the excised root, and solved by an analogue programme. A good fit of the experimentally determined values of water flux, salt flux and exudate salt concentration has been obtained providing the osmotic permeability of the root is allowed to vary with distance from the root tip. The anatomical identity of the exudate channel is discussed, but no firm assignment can be made.

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Unveiling the kinematics of the avoidance response in maize (Zen mays) primary roots

Biologia ◽

10.1515/biolog-2016-0022 ◽

2016 ◽

Vol 71 (2) ◽

Cited By ~ 1

Author(s):

Liyana Popova ◽

Alice Tonazzini ◽

Federica Di Michele ◽

Andrea Russino ◽

Ali Sadeghi ◽

...

Keyword(s):

Mathematical Model ◽

Energy Expenditure ◽

Avoidance Response ◽

Characteristic Time ◽

Time Lapse ◽

Root Tip ◽

Heterogeneous Environment ◽

Primary Roots ◽

Physical Barriers ◽

Time Lapse Imaging

AbstractLiving roots grow in soil, which is a heterogeneous environment containing a wide variety of physical barriers. Roots must avoid these barriers to grow: first, they adopt a characteristic S-shape that can be described by the angle between the root tip and the barrier (i.e., the tip-to-barrier angle); then, they move parallel to the barrier by keeping the sensitive tip in contact with the barrier until it has been circumvented. We investigated this avoidance response in the primary roots of maize (We measured the root tip orientation during growth by using time-lapse imaging and specially developed tip-tracking software (9 trials for each value of the barrier orientation). Remarkably, we found that the S-shapes formed by the roots were characterized by the same tip-to-barrier angle regardless of the barrier orientation: namely, 21.96 ± 2.97, 21.48 ± 4.75 and 20.81 ± 9.39 degrees for barriers oriented at 45, 60 and 90 degrees, respectively. We also considered the root growth after bypassing the barrier; for the barrier at 90 degrees, we observed a gravitropic recovery. Furthermore, we used a mathematical model to quantify the characteristic time of S-shape formation (95 min on average) and gravitropic recovery (approximately 42 min); the obtained values are consistent with those of previous studies.Our results suggest that the avoidance response develops with respect to a reference frame associated with the barrier. From a biological viewpoint, the reason the root adopts the specifically observed tip-to-barrier angle is unclear, but we speculate that maize root optimizes energy expenditure during the penetration of a medium.

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Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094401 ◽

1972 ◽

Vol 30 ◽

pp. 230-231

Author(s):

James Cronshaw ◽

Jamison E. Gilder

Keyword(s):

Plasma Membrane ◽

Atpase Activity ◽

Adenosine Triphosphatase ◽

Higher Plants ◽

High Surface ◽

Root Tip ◽

Animal Cells ◽

Physiological Processes ◽

Tip Cells ◽

Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

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Soil compaction and organic matter affect conifer seedling nonmycorrhizal and ectomycorrhizal root tip abundance and diversity.

10.2737/pnw-rp-494 ◽

1996 ◽

Cited By ~ 9

Author(s):

Michael P. Amaranthus ◽

Debbie Page-Dumroese ◽

Al Harvey ◽

Efren Cazares ◽

Larry F. Bednar

Keyword(s):

Organic Matter ◽

Soil Compaction ◽

Root Tip ◽

Abundance And Diversity ◽

Conifer Seedling

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