Response of cabbage root hairs to infection by Plasmodiophora brassicae

Cabbage root hairs provide a useful system for studying responses to infection by Plasmodiophora brassicae at the cellular level. Roots of cabbage seedlings grown in liquid culture were inoculated with zoospores of P. brassicae, and the effects of infection on host nucleolar development and root hair cell extension were studied. Within 18 h after the root hairs emerged from the trichoblasts the nucleoli of noninfected cells declined in diameter from 5 μ to less than 1 μ. Root hairs which became infected, whether 6 h old or 24 hold, had a nucleolar diameter ranging between 1.5 and 3 μ. The diameter of the nucleolus did not increase above 1.5–3 μ regardless of the age and number of Plasmodia within the cell. In addition to nucleolar enlargement, parasitized cells became stunted and often enlarged at their tips. Growth of Plasmodia within hair cells occurred with synchronous division of their nuclei. After penetration by the parasite there was an 18 h lag before the first nuclear division within the Plasmodia after which synchronous nuclear division occurred at about 4-h intervals.

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Identical Accumulation and Immobilization of Sulfated and Nonsulfated Nod Factors in Host and Nonhost Root Hair Cell Walls

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.10.884 ◽

2003 ◽

Vol 16 (10) ◽

pp. 884-892 ◽

Cited By ~ 15

Author(s):

Joachim Goedhart ◽

Jean-Jacques Bono ◽

Ton Bisseling ◽

Theodorus W. J. Gadella

Keyword(s):

Hair Cell ◽

Root Hair ◽

Cell Walls ◽

Root Hairs ◽

Sharp Decrease ◽

Biologically Active ◽

Nod Factors ◽

Nod Factor ◽

Root Hair Cell ◽

Root Hair Deformation

Nod factors are signaling molecules secreted by Rhizobium bacteria. These lipo-chitooligosaccharides (LCOs) are required for symbiosis with legumes and can elicit specific responses at subnanomolar concentrations on a compatible host. How plants perceive LCOs is unclear. In this study, using fluorescent Nod factor analogs, we investigated whether sulfated and nonsulfated Nod factors were bound and perceived differently by Medicago truncatula and Vicia sativa root hairs. The bioactivity of three novel sulfated fluorescent LCOs was tested in a root hair deformation assay on M. truncatula, showing bioactivity down to 0.1 to 1 nM. Fluorescence microscopy of plasmolyzed M. truncatula root hairs shows that sulfated fluorescent Nod factors accumulate in the cell wall of root hairs, whereas they are absent from the plasma membrane when applied at 10 nM. When the fluorescent Nod factor distribution in medium surrounding a root was studied, a sharp decrease in fluorescence close to the root hairs was observed, visualizing the remarkable capacity of root hairs to absorb Nod factors from the medium. Fluorescence correlation microscopy was used to study in detail the mobilities of sulfated and nonsulfated fluorescent Nod factors which are biologically active on M. truncatula and V. sativa, respectively. Remarkably, no difference between sulfated and nonsulfated Nod factors was observed: both hardly diffuse and strongly accumulate in root hair cell walls of both M. truncatula and V. sativa. The implications for the mode of Nod factor perception are discussed.

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Faculty Opinions recommendation of Functional conservation of a root hair cell-specific cis-element in angiosperms with different root hair distribution patterns.

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

10.3410/f.1051544.503448 ◽

2006 ◽

Author(s):

Liam Dolan

Keyword(s):

Hair Cell ◽

Root Hair ◽

Distribution Patterns ◽

Functional Conservation ◽

Cis Element ◽

Root Hair Cell

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Arabidopsis thaliana Root Hair Cell Cytoplasmic pH (pHc) Imaging

BIO-PROTOCOL ◽

10.21769/bioprotoc.1438 ◽

2015 ◽

Vol 5 (7) ◽

Author(s):

Ling Bai ◽

Yun Zhou ◽

Pengtao Wang ◽

Chun-Peng Song

Keyword(s):

Arabidopsis Thaliana ◽

Hair Cell ◽

Root Hair ◽

Cytoplasmic Ph ◽

Root Hair Cell

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The TOR–Auxin Connection Upstream of Root Hair Growth

Plants ◽

10.3390/plants10010150 ◽

2021 ◽

Vol 10 (1) ◽

pp. 150 ◽

Cited By ~ 1

Author(s):

Katarzyna Retzer ◽

Wolfram Weckwerth

Keyword(s):

Cell Fate ◽

Root Hair ◽

Hair Growth ◽

Environmental Changes ◽

Growth Control ◽

Root Hairs ◽

Signaling Cascades ◽

Continuous Growth ◽

Root Hair Cell ◽

Root Hair Growth

Plant growth and productivity are orchestrated by a network of signaling cascades involved in balancing responses to perceived environmental changes with resource availability. Vascular plants are divided into the shoot, an aboveground organ where sugar is synthesized, and the underground located root. Continuous growth requires the generation of energy in the form of carbohydrates in the leaves upon photosynthesis and uptake of nutrients and water through root hairs. Root hair outgrowth depends on the overall condition of the plant and its energy level must be high enough to maintain root growth. TARGET OF RAPAMYCIN (TOR)-mediated signaling cascades serve as a hub to evaluate which resources are needed to respond to external stimuli and which are available to maintain proper plant adaptation. Root hair growth further requires appropriate distribution of the phytohormone auxin, which primes root hair cell fate and triggers root hair elongation. Auxin is transported in an active, directed manner by a plasma membrane located carrier. The auxin efflux carrier PIN-FORMED 2 is necessary to transport auxin to root hair cells, followed by subcellular rearrangements involved in root hair outgrowth. This review presents an overview of events upstream and downstream of PIN2 action, which are involved in root hair growth control.

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The life history of Plasmodiophora brassicae Woron

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

10.1098/rspb.1972.0008 ◽

1972 ◽

Vol 180 (1058) ◽

pp. 103-112 ◽

Cited By ~ 109

Keyword(s):

Life History ◽

Root Hair ◽

Plasmodiophora Brassicae ◽

Root Hairs ◽

Secondary Phase ◽

Tissue Cultures ◽

Resting Spore ◽

Resting Spores ◽

Seedling Roots ◽

History Of

Resting spore germination and the root hair stages of the life history of Plasmodiophora brassicae were studied in stained preparations of infected Brassica rapa seedling roots. Naked protoplasts, usually possessing two unequal flagella, were released from resting spores through a small circular pore. They penetrated the root hairs of B. rapa and there developed into plasmodia which, after becoming multinucleate, cleaved to form zoosporangia containing incipient zoospores. Biflagellate zoospores were released from root hair zoosporangia and fused in pairs, although karyogamy did not occur. The resulting binucleate zoospores infected the cortical dells of B. rapa to form binucleate plasmodia, the earliest stages of the secondary phase of the life history. These findings are discussed in relation to previous studies on the life history of P. brassicae in Brassica plants and in Brassica tissue cultures, and a new complete life history, including nuclear fusion in the secondary plasmodium, is suggested for the organism.

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Root hair deformation in the infection process of Alnus rubra

Canadian Journal of Botany ◽

10.1139/b83-319 ◽

1983 ◽

Vol 61 (11) ◽

pp. 2863-2876 ◽

Cited By ~ 49

Author(s):

Alison M. Berry ◽

John G. Torrey

Keyword(s):

Root Hair ◽

Cell Walls ◽

Root Hairs ◽

Infection Process ◽

Alnus Rubra ◽

Pseudomonas Cepacia ◽

Developmental Studies ◽

Experimental Conditions ◽

Root Hair Cell ◽

Root Hair Deformation

Structural and cell developmental studies of root hair deformation in Alnus rubra Bong. (Betulaceae) were carried out following inoculation with the soil pseudomonad Pseudomonas cepacia 85, alone or in concert with Frankia, and using axenically grown seedlings. Deformational changes can be observed in elongating root hairs within 2 h of inoculation with P. cepacia 85. These growing root hairs become branched or multilobed and highly modified from the single-tip growth of axenic root hairs. The cell walls of deformed hairs are histologically distinctive when stained with the fluorochrome acridine orange. Filtrate studies using P. cepacia 85 suggest that the deforming substance is not a low molecular weight compound. Root hair deformation and the associated wall histology are host specific in that Betula root hairs show none of these responses when grown and inoculated in the experimental conditions described. The bacterially induced changes in root hair cell walls during deformation may create a chemically and physically modified substrate for Frankia penetration, and the deformation itself may serve to entrap and enclose the filamentous organism, allowing wall dissolution and entry. Thus these events represent a complex host response as a precondition to successful nodulation.

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CLE14 peptide signaling in Arabidopsis root hair cell fate determination

Plant Biotechnology ◽

10.5511/plantbiotechnology.18.0122a ◽

2018 ◽

Vol 35 (1) ◽

pp. 17-22 ◽

Cited By ~ 5

Author(s):

Naoto Hayashi ◽

Takuya Tetsumura ◽

Shinichiro Sawa ◽

Takuji Wada ◽

Rumi Tominaga-Wada

Keyword(s):

Hair Cell ◽

Cell Fate ◽

Root Hair ◽

Cell Fate Determination ◽

Arabidopsis Root ◽

Fate Determination ◽

Peptide Signaling ◽

Root Hair Cell

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Brassinosteroids control root epidermal cell fate via direct regulation of a MYB-bHLH-WD40 complex by GSK3-like kinases

eLife ◽

10.7554/elife.02525 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 54

Author(s):

Yinwei Cheng ◽

Wenjiao Zhu ◽

Yuxiao Chen ◽

Shinsaku Ito ◽

Tadao Asami ◽

...

Keyword(s):

Hair Cell ◽

Cell Fate ◽

Epidermal Cell ◽

Hair Cells ◽

Root Hair ◽

Cell Nuclei ◽

Brassinosteroid Signaling ◽

Root Hair Formation ◽

A Cell ◽

Transcriptional Complex

In Arabidopsis, root hair and non-hair cell fates are determined by a MYB-bHLH-WD40 transcriptional complex and are regulated by many internal and environmental cues. Brassinosteroids play important roles in regulating root hair specification by unknown mechanisms. Here, we systematically examined root hair phenotypes in brassinosteroid-related mutants, and found that brassinosteroid signaling inhibits root hair formation through GSK3-like kinases or upstream components. We found that with enhanced brassinosteroid signaling, GL2, a cell fate marker for non-hair cells, is ectopically expressed in hair cells, while its expression in non-hair cells is suppressed when brassinosteroid signaling is reduced. Genetic analysis demonstrated that brassinosteroid-regulated root epidermal cell patterning is dependent on the WER-GL3/EGL3-TTG1 transcriptional complex. One of the GSK3-like kinases, BIN2, interacted with and phosphorylated EGL3, and EGL3s mutated at phosphorylation sites were retained in hair cell nuclei. BIN2 phosphorylated TTG1 to inhibit the activity of the WER-GL3/EGL3-TTG1 complex. Thus, our study provides insights into the mechanism of brassinosteroid regulation of root hair patterning.

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