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.

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 Nod Factor-Induced Expression of Leghemoglobin to Study the Mechanism of NH4NO3 Inhibition on Root Hair Deformation

1997 ◽  
Vol 10 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Renze Heidstra ◽  
Gerd Nilsen ◽  
Francisco Martinez-Abarca ◽  
Ab van Kammen ◽  
Ton Bisseling
Keyword(s):  
Gene Expression ◽  
Root Hair ◽  
Rhizobium Leguminosarum ◽  
Cortical Cell ◽  
Brefeldin A ◽  
Marker Genes ◽  
Nodule Formation ◽  
Cdna Clones ◽  
Nod Factor ◽  
Root Hair Deformation

Nod factors secreted by Rhizobium leguminosarum bv. viciae induce root hair deformation, the formation of nodule primordia, and the expression of early nodulin genes in Vicia sativa (vetch). Root hair deformation is induced within 3 h in a small, susceptible zone (±2 mm) of the root. NH4NO3, known to be a potent blocker of nodule formation, inhibits root hair deformation, initial cortical cell divisions, and infection thread formation. To test whether NH4NO3 affects the formation of a component of the Nod factor perception-transduction system, we studied Nod factor-induced gene expression. The differential display technique was used to search for marker genes, which are induced within 1 to 3 h after Nod factor application. Surprisingly, one of the isolated cDNA clones was identified as a leghemoglobin gene (VsLb1), which is induced in vetch roots within 1 h after Nod factor application. By using the drug brefeldin A, it was then shown that VsLb1 activation does not require root hair deformation. The pVsLb1 clone was used as a marker to show that in vetch plants grown in the presence of NH4NO3 Nod factor perception and transduction leading to gene expression are unaffected.

Diffusible factors from Frankia modify nodulation kinetics in Discaria trinervis, an intercellular root-infected actinorhizal symbiosis

2011 ◽  
Vol 38 (9) ◽  
pp. 662 ◽  
Author(s):  
Luciano Andrés Gabbarini ◽  
Luis Gabriel Wall
Keyword(s):  
Root Hair ◽  
Root Nodules ◽  
Root Hairs ◽  
Basic Structure ◽  
Peptide Bond ◽  
Nodule Development ◽  
Actinorhizal Symbiosis ◽  
Biochemical Characterisation ◽  
Clade 1 ◽  
Discaria Trinervis

Frankia BCU110501 induces nitrogen-fixing root nodules in Discaria trinervis (Gillies ex Hook. & Arn.) Reiche (Rhamnaceae) via intercellular colonisation, without root hair deformation. It produces diffusible factors (DFs) that might be involved in early interactions with the D. trinervis roots, playing a role in the nodulation process. The induction of root nodule development in actinorhizal symbiosis would depend on the concentration of factors produced by the bacteria and the plant. A detailed analysis of nodulation kinetics revealed that these DFs produce changes at the level of initial rate of nodulation and also in nodulation profile. Diluted Frankia BCU110501 inoculum could be activated in less than 96 h by DFs produced by Frankia BCU110501 cells that had been previously washed. Biochemical characterisation showed that Frankia BCU110501 DFs have a molecular weight of <12 kDa, are negatively charged at pH 7.0 and seem to contain a peptide bond necessary for their activity. Frankia BCU110501, belonging to Frankia Clade 3, does not induce nodules in Alnus acuminata H.B.K. ssp. acuminata but is able to deform root hairs, as do Frankia strains from Clade 1. The root hair deforming activity of Frankia BCU110501 DFs show the same biochemical characteristics of the DFs involved in nodulation of D. trinervis. These results suggest that Frankia symbiotic factors have a basic structure regardless of the infection pathway of the host plant.

scholarly journals Development of Ectopic Roots from Abortive Nodule Primordia

2004 ◽  
Vol 17 (10) ◽  
pp. 1043-1050 ◽  
Author(s):  
Simona Ferraioli ◽  
Rosarita Tatè ◽  
Alessandra Rogato ◽  
Maurizio Chiurazzi ◽  
Eduardo J. Patriarca
Keyword(s):  
Root Hair ◽  
Nodule Development ◽  
Bacterial Invasion ◽  
Meristematic Tissue ◽  
Root Hair Deformation ◽  
Conditional Mutant ◽  
Infection Threads ◽  
Induced Mutants ◽  
Symbiotic Phenotype ◽  
Nodulin Genes

The symbiotic phenotype of five Tn5-induced mutants of Rhizobium etli affected in different anabolic pathways (namely, gluconeogenesis and biosynthesis of lysine, purine, or pyrimidine) was analyzed. These mutants induced, on the root of Phaseolus vulgaris, a normal early sequence of morphogenetics events, including root hair deformation and development of nodule primordia. Later on, however, from the resulting root outgrowths, instead of nodules, one or more ectopic roots (spaced closely related and agravitropic) emerged. Therefore, this group of mutant was collectively called “root inducer” (RIND). It was observed that the RIND-induced infection threads aborted early inside the invaded root hair, and that the resulting abortive nodules lack induction of late nodulin genes. Moreover, experiments performed using a conditional mutant (a methionine-requiring invader) revealed that bacterial invasion plays a key role in the maintenance of the program of nodule development and, in particular, in the differentiation of the most specific symbiotic tissue of globose nodules, the central tissue. These data indicate that, in P. vulgaris, the nodule primordium is a root-specified pro-meristematic tissue.

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

Newly featured infection events in a supernodulating soybean mutant SS2-2 by Bradyrhizobium japonicum

2006 ◽  
Vol 52 (4) ◽  
pp. 328-335 ◽  
Author(s):  
Puji Lestari ◽  
Kyujung Van ◽  
Moon Young Kim ◽  
Byun-Woo Lee ◽  
Suk-Ha Lee
Keyword(s):  
Glycine Max ◽  
Bradyrhizobium Japonicum ◽  
Cortical Cell ◽  
Root Hairs ◽  
Nodule Development ◽  
Nodule Formation ◽  
Vascular Bundles ◽  
Wild Type ◽  
In The Wild ◽  
Supernodulating Mutant

Supernodulating soybean (Glycine max L. Merr.) mutant SS2-2 and its wild-type counterpart, Sinpaldalkong 2, were examined for the microstructural events associated with nodule formation and development. SS2-2 produced a substantially higher percentage of curled root hairs than the wild type, especially at 14 days after inoculation with Bradyrhizobium japonicum. In addition, there was new evidence that in SS2-2, B. japonicum also entered through fissures created by the emerging adventitious root primordia. Early steps of nodule ontogeny were faster in SS2-2, and continued development of initiated nodules was more frequent and occurred at a higher frequency than in the wild type. These data suggest that the early expression of autoregulation is facilitated by decreasing the speed of cortical cell development, leading to the subsequent termination of less-developed nodules. The nodules of SS2-2 developed into spherical nodules like those formed on the wild type. In both the wild type and supernodulating mutant, vascular bundles bifurcate from root stele and branch off in the nodule cortex to surround the central infected zone. These findings indicate that SS2-2 has complete endosymbiosis and forms completely developed nodule vascular bundles like the wild type, but that the speed of nodule ontogeny differs between the wild type and SS2-2. Thus, SS2-2 has a novel symbiotic phenotype with regard to nodule organogenesis.Key words: Bradyrhizobium japonicum, early nodule development, Glycine max, root hair curling, supernodulation.

Determinate development of nodule roots in actinomycete-induced root nodules of Myrica gale

1978 ◽  
Vol 56 (11) ◽  
pp. 1357-1364 ◽  
Author(s):  
John G. Torrey ◽  
Dale Callaham
Keyword(s):  
Root Development ◽  
Root Nodules ◽  
Cortical Cell ◽  
Gas Diffusion ◽  
Nodule Development ◽  
Nodule Formation ◽  
Low Oxygen ◽  
Cortical Cells ◽  
Continuous Growth ◽  
Myrica Gale

Young seedlings of Myrica gale L. grown in water culture were inoculated with a nodule suspension containing the effective actinomycete which induced root nodule formation. Nodule development was followed from initiation to nodule lobe formation and nodule root development using living materials and fixed nodules sectioned for light microscopy. After root hair infection and prenodule formation, three stages were observed: nodule lobe formation, a transition or arrested state, and nodule root development. The primary nodule lobe meristem originates endogenously and its formation involves pericycle, endodermis, and cortical cell derivatives. The lobe develops slowly to about 2 mm in length while the cortical cells are invaded by the actinomycete endophyte. After a period of arrest of variable duration, from a few days to several weeks, the nodule lobe meristem begins altered development, forming the elongate nodule root which undergoes slow but continuous growth to about 3- to 4-cm final length. New nodule lobe primordia are initiated endogenously at the base of existing nodules lobes, ultimately forming a cluster of nodule roots. Each nodule root, which elongates at about 0.1–1.0 mm per day, has a terminal apical meristem with reduced root cap formation and produces a modified root structure possessing an elaborate cortical intercellular space system and a reduced central cylinder. Nodule root growth is distinctive in that it shows strong negative geotropism. The endophyte is restricted to cortical cells of the nodule lobe and is totally absent from tissues of the nodule root. A probable role for nodule roots is to facilitate gas diffusion to the nitrogen-fixing endophyte site in the nodule lobe when nodules occur under conditions of low oxygen tension.

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.

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