scholarly journals Rhizobia Modulate Root-Hair-Specific Expression of Extensin Genes

1997 ◽  
Vol 10 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Ivana Arsenijevic-Maksimovic ◽  
William J. Broughton ◽  
Andrea Krause
Keyword(s):  
Root Hair ◽  
Promoter Region ◽  
Root Hairs ◽  
Mrna Levels ◽  
Genomic Locus ◽  
Gene Encoding ◽  
Specific Expression ◽  
Transcript Levels ◽  
Root Hair Deformation ◽  
Lectin Promoter

Three cDNAs (ext3, ext127, and ext26), originally isolated by differential screening from a root-hair cDNA library of Vigna unguiculata, were found to encode extensin-like cell wall proteins. Transcripts homologous to these cDNAs were only detected in root hairs where mRNA levels decreased 1 day after inoculation with rhizobia. This coincided with the onset of root-hair deformation, the first morphological step in the Rhizobium-legume interaction. Decreases in transcript levels following inoculation with wild-type Rhizobium sp. NGR234 were more pronounced than with NGRΔnodABC, a mutant deficient in Nod-factor production. Inoculation with a rhizobial strain carrying a mutation in a gene encoding a transcriptional activator for nod genes (NGRΔnodD1) did not repress mRNA levels, indicating that a second nodulation signal may be present that is nodD dependent. Application of purified NodNGR factors only affected transcript levels of ext3. The genomic locus of the gene homologous to ext26 (Ext26G) was cloned. In the 5′ flanking region, several potential TATA boxes and CAP signals were identified. Part of the promoter region shares homology with the Pisum sativum seed lectin promoter and the Nicotiana tabacum nitrate reductase promoter region. Nonetheless, the function of these homologous regions in gene regulation is unknown.

Root hair deformation in the infection process of Alnus rubra

1983 ◽  
Vol 61 (11) ◽  
pp. 2863-2876 ◽  
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.

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

2003 ◽  
Vol 16 (10) ◽  
pp. 884-892 ◽  
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.

scholarly journals The Small GTPase ROP10 of Medicago truncatula Is Required for Both Tip Growth of Root Hairs and Nod Factor-Induced Root Hair Deformation

2015 ◽  
Vol 27 (3) ◽  
pp. 806-822 ◽  
Author(s):  
Ming-Juan Lei ◽  
Qi Wang ◽  
Xiaolin Li ◽  
Aimin Chen ◽  
Li Luo ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
Small Gtpase ◽  
Nod Factor ◽  
Root Hair Deformation

Expression of a gene encoding a glycine-rich protein in petunia

1987 ◽  
Vol 7 (12) ◽  
pp. 4273-4279
Author(s):  
C M Condit ◽  
R B Meagher
Keyword(s):  
Developmental Regulation ◽  
Transcriptional Start Site ◽  
Wound Response ◽  
Mrna Levels ◽  
Structural Protein ◽  
Gene Encoding ◽  
Specific Expression ◽  
Organ Specific ◽  
Young Leaves ◽  
Steady State Levels

We have investigated the expression of a gene that codes for a glycine-rich structural protein (GRP1) in petunia. This gene is expressed as a single polyadenylated RNA of approximately 1,600 bases which was found to be present in leaves, stems, and flowers of petunia but not in roots. In the organs in which GRP1-specific mRNA was expressed, its steady-state levels were highest in stems and leaves and lowest in flowers. This analysis also revealed that the pattern of organ-specific expression for several of the GRP1-related genes was distinctly different. In addition, it was found that the levels of GRP1 RNA were significantly higher in young leaves and stems than in old, implying developmental regulation of the gene. GRP1-specific RNA in both old and young tissue that had been wounded was found to be increased at least 25-fold over that in young unwounded tissue. Increased levels of GRP1 mRNA were seen within 5 min after wounding, with substantial increases apparent by 30 min. Maximal levels of accumulation of GRP1 transcripts occurred 90 min after wounding. The enhancement of GRP1 mRNA levels by wounding appears to be one of the earliest events of the plant wound response and is distinct from that which we observed for the PAL gene in petunia. Using S1 analysis and RNA primer extension, we demonstrated that the same transcriptional start site was used by the GRP1 gene in all organs and in wounded and unwounded tissue. The potential significance of these data with regard to wound signal transduction is discussed.

scholarly journals Expression of a gene encoding a glycine-rich protein in petunia.

1987 ◽  
Vol 7 (12) ◽  
pp. 4273-4279 ◽  
Author(s):  
C M Condit ◽  
R B Meagher
Keyword(s):  
Developmental Regulation ◽  
Transcriptional Start Site ◽  
Wound Response ◽  
Mrna Levels ◽  
Structural Protein ◽  
Gene Encoding ◽  
Specific Expression ◽  
Organ Specific ◽  
Young Leaves ◽  
Steady State Levels

We have investigated the expression of a gene that codes for a glycine-rich structural protein (GRP1) in petunia. This gene is expressed as a single polyadenylated RNA of approximately 1,600 bases which was found to be present in leaves, stems, and flowers of petunia but not in roots. In the organs in which GRP1-specific mRNA was expressed, its steady-state levels were highest in stems and leaves and lowest in flowers. This analysis also revealed that the pattern of organ-specific expression for several of the GRP1-related genes was distinctly different. In addition, it was found that the levels of GRP1 RNA were significantly higher in young leaves and stems than in old, implying developmental regulation of the gene. GRP1-specific RNA in both old and young tissue that had been wounded was found to be increased at least 25-fold over that in young unwounded tissue. Increased levels of GRP1 mRNA were seen within 5 min after wounding, with substantial increases apparent by 30 min. Maximal levels of accumulation of GRP1 transcripts occurred 90 min after wounding. The enhancement of GRP1 mRNA levels by wounding appears to be one of the earliest events of the plant wound response and is distinct from that which we observed for the PAL gene in petunia. Using S1 analysis and RNA primer extension, we demonstrated that the same transcriptional start site was used by the GRP1 gene in all organs and in wounded and unwounded tissue. The potential significance of these data with regard to wound signal transduction is discussed.

scholarly journals Rapid, Plateau-like Increases in Intracellular Free Calcium Are Associated with Nod-Factor—Induced Root-Hair Deformation

1997 ◽  
Vol 10 (7) ◽  
pp. 791-802 ◽  
Author(s):  
Christoph A. Gehring ◽  
Helen R. Irving ◽  
Akram A. Kabbara ◽  
Roger W. Parish ◽  
Nawal M. Boukli ◽  
...  
Keyword(s):  
Root Hair ◽  
Root Hairs ◽  
Epidermal Cells ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Broad Host Range ◽  
Nod Factors ◽  
Root Cortex ◽  
Cellular Events ◽  
Root Hair Deformation

Rhizobia excrete variously substituted lipo-oligosaccha-ride Nod factors into the legume rhizosphere. Homologous legumes respond to these signals through deformation of the root hairs and the development of nodulation foci in the root cortex. Cellular events in root hairs from the susceptible zone of nearly mature root hairs were studied in root segments loaded with the calcium indicators Fura-2 or Fluo-3. Application of 10-9 M Nod factors of the broad-host-range Rhizobium sp. NGR234 to the homologous legume Vigna unguiculata resulted, within seconds, in plateau-like increases in intracellular free calcium ([Ca2+]i) in the root hairs and root epidermal cells. Nod factors of R. meliloti at 10-9 M caused equally rapid increases in [Ca2+]i in the root hairs and epidermal cells of the nonhost V. unguiculata, and also induced root-hair deformation. The chitin tetramer, N-N′-N″-N′″-tetracetylchitotetraose, which represents the backbone of Nod factors, induced neither root-hair deformation nor changes in [Ca2+]i in V. unguiculata. Root hairs and epidermal cells of the nonlegume non-host Arabidopsis thaliana showed neither [Ca2+]i increases nor root-hair deformation in response to both factors.

scholarly journals Inhibition of Pre-mRNA Splicing Promotes Root Hair Development in Arabidopsis thaliana

2019 ◽  
Vol 60 (9) ◽  
pp. 1974-1985 ◽  
Author(s):  
Miku Ishizawa ◽  
Kayo Hashimoto ◽  
Misato Ohtani ◽  
Ryosuke Sano ◽  
Yukio Kurihara ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Hair ◽  
Protein A ◽  
Root Hairs ◽  
Carbon Dioxide Concentration ◽  
Light Response ◽  
Mrna Splicing ◽  
Gene Encoding ◽  
Root Hair Development ◽  
Hair Development

Abstract Root hairs protruding from epidermal cells increase the surface area for water absorption and nutrient uptake. Various environmental factors including light, oxygen concentration, carbon dioxide concentration, calcium and mycorrhizal associations promote root hair formation in Arabidopsis thaliana. Light regulates the expression of a large number of genes at the transcriptional and post-transcriptional levels; however, there is little information linking the light response to root hair development. In this study, we describe a novel mutant, light-sensitive root-hair development 1 (lrh1), that displays enhanced root hair development in response to light. Hypocotyl and root elongation was inhibited in the lrh1 mutant, which had a late flowering phenotype. We identified the gene encoding the p14 protein, a putative component of the splicing factor 3b complex essential for pre-mRNA splicing, as being responsible for the lrh1 phenotype. Indeed, regulation of alternative splicing was affected in lrh1 mutants and treatment with a splicing inhibitor mimicked the lrh1 phenotype. Genome-wide alterations in pre-mRNA splicing patterns including differential splicing events of light signaling- and circadian clock-related genes were found in lrh1 as well as a difference in transcriptional regulation of multiple genes including upregulation of essential genes for root hair development. These results suggest that pre-mRNA splicing is the key mechanism regulating root hair development in response to light signals.

scholarly journals GmYUC2a mediates auxin biosynthesis during root development and nodulation in soybean

2019 ◽  
Vol 70 (12) ◽  
pp. 3165-3176 ◽  
Author(s):  
Youning Wang ◽  
Wei Yang ◽  
Yanyan Zuo ◽  
Lin Zhu ◽  
April H Hastwell ◽  
...  
Keyword(s):  
Root Development ◽  
Root Hair ◽  
Root Hairs ◽  
Auxin Biosynthesis ◽  
Nodule Development ◽  
Nodule Formation ◽  
Growth Defects ◽  
Auxin Production ◽  
Primary Roots ◽  
Root Hair Deformation

Abstract Auxin plays central roles in rhizobial infection and nodule development in legumes. However, the sources of auxin during nodulation are unknown. In this study, we analyzed the YUCCA (YUC) gene family of soybean and identified GmYUC2a as an important regulator of auxin biosynthesis that modulates nodulation. Following rhizobial infection, GmYUC2a exhibited increased expression in various nodule tissues. Overexpression of GmYUC2a (35S::GmYUC2a) increased auxin production in soybean, resulting in severe growth defects in root hairs and root development. Upon rhizobial infection, 35S::GmYUC2a hairy roots displayed altered patterns of root hair deformation and nodule formation. Root hair deformation occurred mainly on primary roots, and nodules formed exclusively on primary roots of 35S::GmYUC2a plants. Moreover, transgenic 35S::GmYUC2a composite plants showed delayed nodule development and a reduced number of nodules. Our results suggest that GmYUC2a plays an important role in regulating both root growth and nodulation by modulating auxin balance in soybean.

SEM and fluorescence imaging of callose deposition in root hair tips and suspension cultures of Streptanthus tortuosus

1990 ◽  
Vol 48 (3) ◽  
pp. 698-699
Author(s):  
K.S. Walters ◽  
R.D. Sjolund ◽  
K.C. Moore
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Cultured Cells ◽  
Root Hairs ◽  
Callus Cultures ◽  
Callose Deposition ◽  
Culture Cells ◽  
Wall Structures ◽  
Ultraviolet Illumination ◽  
Callose Formation

Callose, B-1,3-glucan, a component of cell walls, is associated with phloem sieve plates, plasmodesmata, and other cell wall structures that are formed in response to wounding or infection. Callose reacts with aniline blue to form a fluorescent complex that can be recognized in the light microscope with ultraviolet illumination. We have identified callose in cell wall protuberances that are formed spontaneously in suspension-cultured cells of S. tortuosus and in the tips of root hairs formed in sterile callus cultures of S. tortuosus. Callose deposits in root hairs are restricted to root hair tips which appear to be damaged or deformed, while normal root hair tips lack callose deposits. The callose deposits found in suspension culture cells are restricted to regions where unusual outgrowths or protuberances are formed on the cell surfaces, specifically regions that are the sites of new cell wall formation.Callose formation has been shown to be regulated by intracellular calcium levels.

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