Cortical colonisation is not an absolute requirement for phosphorus transfer to plants in arbuscular mycorrhizas formed by Scutellospora calospora in a tomato mutant: evidence from physiology and gene expression

2010 ◽  
Vol 37 (12) ◽  
pp. 1132 ◽  
Author(s):  
Maria Manjarrez ◽  
Helle M. Christophersen ◽  
Sally E. Smith ◽  
F. Andrew Smith
Keyword(s):  
Gene Expression ◽  
Arbuscular Mycorrhizas ◽  
Physiological Data ◽  
Cortical Cells ◽  
Root Cells ◽  
Absolute Requirement ◽  
Cell Layers ◽  
Mycorrhizal Colonisation ◽  
Hyphal Coils ◽  
Scutellospora Calospora

Arbuscules in Arum-type arbuscular mycorrhizas (AM), formed intracellularly in root cortical cells, are generally believed to be the most important and defining characteristics of the symbiosis as sites for phosphorus (P) and carbon (C) exchange. We used a Pen + Coi– phenotype (penetration of epidermal and exodermal root cells but not arbuscule formation) formed in rmc (reduced mycorrhizal colonisation) mutant tomato (Lycopersicon esculentum Mill.) by Scutellospora calospora (Nicol. & Gerd.) Walker & Sanders to determine whether the fungus is capable of transferring P from soil to plant and whether there is concurrent upregulation of AM-inducible orthophosphate (Pi) transporter gene expression in the roots. Our physiological data showed that colonisation of outer root cell layers is sufficient for P transfer from S. calospora to tomato. This transfer of P was supported by increased expression of the Pi transporter genes, LePT3 and LePT5, known to be upregulated in AM interactions. We conclude that cortical colonisation and formation of arbuscules or arbusculate hyphal coils is not an absolute prerequisite for P transfer in this symbiosis.

A comparative cytological analysis of fungal endophytes in the sporophyte rhizomes and vascularized gametophytes of Tmesipteris and Psilotum

2005 ◽  
Vol 83 (11) ◽  
pp. 1443-1456 ◽  
Author(s):  
Jeffrey G. Duckett ◽  
Roberto Ligrone
Keyword(s):  
Fungal Endophytes ◽  
Vascular Anatomy ◽  
Arbuscular Mycorrhizas ◽  
Wall Material ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Vascular Elements ◽  
Vessel Elements ◽  
Perforation Plates ◽  
Hyphal Coils

This article describes the results of a light and electron microscopic study of the fungal endophytes and vascular anatomy in the rhizomes and gametophytes of Tmesipteris and Psilotum. The parenchymatous cortical cells of the rhizomes and subterranean gametophytes of Tmesipteris and Psilotum contain intracellular aseptate glomeromycotean fungi resembling the “Paris-type” of arbuscular mycorrhizas found in seed plants. The fungi differentiate into multinucleate vesicles and hyphal coils, both containing bacteria-like structures and accumulating lipid masses and crystals as they age. After several cycles of infection in the same cell, degenerate hyphae form amorphous masses encased by host wall material. Nearly identical host–fungus cytology between the autotrophic sporophytes and the heterotrophic gametophytes suggests that these psilophyte associations are exploitative of the fungus in both generations. Following the description of tracheids nearly 60 years ago in the gametophytes of Psilotum, vascular elements are described for the first time in the haploid generation of Tmesipteris. Close similarities between the water- and food-conducting elements in both generations, viz. vessel elements with scalariform perforation plates and sieve cells with refractive spherules and lacking callose at all stages in their develoment, add support to the homologous theory of the alternations of generations. Mitochondrial aggregations, cross-linked by small electron-opaque rods, are common in the stelar cells of both generations and appear to be a unique feature of the psilophyte clade.

Short-and long-term effects of cadmium on transmembrane electric potential (E m) in maize roots

Biologia ◽  
2006 ◽  
Vol 61 (1) ◽  
Author(s):  
Ján Pavlovkin ◽  
Miroslava Luxová ◽  
Ingrid Mistríková ◽  
Igor Mistrík
Keyword(s):  
Root Growth ◽  
Electric Potential ◽  
Time Course ◽  
Cumulative Effect ◽  
Significant Inhibition ◽  
Long Term Effects ◽  
Cortical Cells ◽  
Root Cells ◽  
Maize Roots ◽  
Atp Supply

AbstractIn this study, the effects of Cd on root growth, respiration, and transmembrane electric potential (E m) of the outer cortical cells in maize roots treated with various Cd concentrations (from 1 µM to 1 mM) for several hours to one week were studied. The E m values of root cells ranged between −120 and −140 mV and after addition of Cd they were depolarized immediately. The depolarization was concentration-dependent reaching the value of diffusion potential (E D) when the Cd concentration exceeded 100 µM. The values of E D ranged between −65 to −68 mV (−66 ± 1.42 mV). The maximum depolarization of E m was registered approx. 2.5 h after addition of Cd to the perfusion solution and in some cases, partial (Cd > 100 µM) or complete repolarization (Cd < 100 µM) was observed within 8–10 h of Cd treatment. In the time-dependent experiments (0 to 168 h) shortly after the maximum repolarization of E m a continuous concentration-dependent decrease of E m followed at all Cd concentrations. Depolarization of E m was accompanied by both increased electrolyte leakage and inhibition of respiration, especially in the range of 50 µM to 1 mM Cd, with the exception of root cells treated with 1 and 10 µM Cd for 24 and 48 h. Time course analysis of Cd impact on root respiration revealed that at higher Cd concentrations (> 50 µM) the respiration gradually declined (∼ 6 h) and then remained at this lowest level for up to 24 h.All the Cd concentrations used in this experiment induced significant inhibition of root elongation and concentrations higher than 100 µM stopped the root growth within the first day of Cd treatment. Our results suggest that Cd does not cause irreversible changes in the electrogenic plasma membrane H+ ATPase because fusicoccin, an H+ ATPase activator diminished the depolarizing effect of Cd on the E m. The depolarization of E m in the outer cortical cells of maize roots was the result of a cumulative effect of Cd on ATP supply, plasmalemma permeability, and activity of H+ ATPase.

scholarly journals Extensive Regulation of Metabolism and Growth during the Cell Division Cycle

2014 ◽  
Author(s):  
Nikolai Slavov ◽  
David Botstein ◽  
Amy Caudy
Keyword(s):  
Gene Expression ◽  
Oxygen Consumption ◽  
Cell Division ◽  
Single Cell ◽  
Single Cells ◽  
Emergent Behavior ◽  
Yeast Cells ◽  
Physiological Data ◽  
Synchronized Cultures ◽  
Metabolic Cycle

Yeast cells grown in culture can spontaneously synchronize their respiration, metabolism, gene expression and cell division. Such metabolic oscillations in synchronized cultures reflect single-cell oscillations, but the relationship between the oscillations in single cells and synchronized cultures is poorly understood. To understand this relationship and the coordination between metabolism and cell division, we collected and analyzed DNA-content, gene-expression and physiological data, at hundreds of time-points, from cultures metabolically-synchronized at different growth rates, carbon sources and biomass densities. The data enabled us to extend and generalize our mechanistic model, based on ensemble average over phases (EAP), connecting the population-average gene-expression of asynchronous cultures to the gene-expression dynamics in the single-cells comprising the cultures. The extended model explains the carbon-source specific growth-rate responses of hundreds of genes. Our physiological data demonstrate that the frequency of metabolic cycling in synchronized cultures increases with the biomass density, suggesting that this cycling is an emergent behavior, resulting from the entraining of the single-cell metabolic cycle by a quorum-sensing mechanism, and thus underscoring the difference between metabolic cycling in single cells and in synchronized cultures. Measurements of constant levels of residual glucose across metabolically synchronized cultures indicate that storage carbohydrates are required to fuel not only the G1/S transition of the division cycle but also the metabolic cycle. Despite the large variation in profiled conditions and in the scale of their dynamics, most genes preserve invariant dynamics of coordination with each other and with the rate of oxygen consumption. Similarly, the G1/S transition always occurs at the beginning, middle or end of the high oxygen consumption phases, analogous to observations in human and drosophila cells. These results highlight evolutionary conserved coordination among metabolism, cell growth and division.

scholarly journals Electroporation-mediated delivery of catalytic oligodeoxynucleotides for manipulation of vascular gene expression

2003 ◽  
Vol 285 (5) ◽  
pp. H2240-H2247 ◽  
Author(s):  
Elizabeth A. Nunamaker ◽  
Hai-Ying Zhang ◽  
Yuichi Shirasawa ◽  
Joseph N. Benoit ◽  
David A. Dean
Keyword(s):  
Gene Expression ◽  
Experimental Studies ◽  
Wild Type ◽  
Protein Levels ◽  
Dna Oligonucleotides ◽  
Pkc Isoforms ◽  
Cell Layers ◽  
Cultured Smooth Muscle Cells ◽  
Decrease Gene Expression

The development of inexpensive and effective approaches to transiently decrease gene expression in vivo would be useful for the study of physiological processes in living animals. DNAzymes are a novel class of DNA oligonucleotides that can catalytically cleave target mRNAs and thereby reduce protein production. However, current methods for their delivery in vivo are limited and inefficient. In this study, we show that electroporation can be used to deliver DNAzymes to the intact mesenteric vasculature of rats. With the use of PKC-ϵ as a target, a set of wild-type and mutant control DNAzymes was designed and shown to reduce both PKC-ϵ mRNA and protein levels in cultured smooth muscle cells in a specific manner. The wild-type DNAzyme reduced PKC-ϵ protein levels by 70% at 24 h in two different cell lines without decreasing the levels of the five other PKC isoforms tested. When delivered to the intact vasculature using electroporation, the DNAzyme reduced PKC-ϵ protein levels by >60% without affecting these other PKC isoforms. Electroporation was required for oligonucleotide transfer and was able to deliver the DNAzymes to multiple cell layers in the vessel wall. Protein levels were reduced maximally by 24 h postelectroporation and returned to normal by 48 h. These results suggest that electroporation can be used to deliver DNAzymes and other DNA oligonucleotides to the vasculature in vivo and can decrease gene expression for a window of time that can be used for experimental studies.

Differences in the colonization of Pinus banksiana roots by sib-monokaryotic and dikaryotic strains of ectomycorrhizal Laccaria bicolor

1989 ◽  
Vol 67 (6) ◽  
pp. 1717-1726 ◽  
Author(s):  
Ken K. Y. Wong ◽  
Yves Piché ◽  
Diane Montpetit ◽  
Bradley R. Kropp
Keyword(s):  
Pinus Banksiana ◽  
Intraspecific Variability ◽  
Root Cell ◽  
Laccaria Bicolor ◽  
Cortical Cells ◽  
Aseptic Culture ◽  
Hartig Net ◽  
Cell Layers ◽  
The Mean ◽  
Root Surfaces

First-order laterals of Pinus banksiana seedlings were inoculated with variant strains of ectomycorrhizal Laccaria bicolor in an aseptic culture system. Macroscopic observations of 10 fungal strains indicated that 6 are mycorrhizal and 4 are apparently nonmycorrhizal. Furthermore, light microscopic examinations revealed significant intraspecific variation in mycorrhizal structures. The mean mantle thickness, mean mantle density, and mean Hartig net penetration of the six mycorrhizal strains ranged from 2.5 to 13.4 hyphae, 278 to 411 hyphae/mm and 2 to 2.8 root cell layers, respectively. Three of these strains formed fewer macroscopically observable mycorrhizae and developed significantly thinner mantles but their Hartig nets usually separated cortical cells more extensively. Three of the four apparently nonmycorrhizal strains showed infrequent and poor Hartig net development (mean penetration of 0.3 to 0.8 root cell layer), poor surface colonization, and no mantle development. These three strains were better able to colonize long roots. Only one strain could be considered truly nonmycorrhizal because it only colonized root surfaces poorly and never showed mantle or Hartig net formation. The observed intraspecific variability raises questions concerning the determinants of mycorrhiza development and structure.

The rmc locus does not affect plant interactions or defence-related gene expression when tomato (Solanum lycopersicum) is infected with the root fungal parasite, Rhizoctonia

2006 ◽  
Vol 33 (3) ◽  
pp. 289 ◽  
Author(s):  
Ling-Ling Gao ◽  
F. Andrew Smith ◽  
Sally E. Smith
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Fungal Species ◽  
Plant Interactions ◽  
Related Gene ◽  
Wild Type ◽  
Cell Layers ◽  
Almost All

A tomato mutant with reduced mycorrhizal colonisation, rmc, confers resistance to almost all arbuscular mycorrhizal (AM) fungal species tested, although there is variation in colonisation of different root cell layers by different fungi and one species of AM fungus can colonise this mutant relatively normally. These variations indicate a high degree of specificity in relation to AM colonisation. We explored the possibility of specificity or otherwise in interactions between rmc and three non-AM root-infecting fungi, Rhizoctonia solani anastomosis groups (AG) 4 and AG8, and binucleate Rhizoctonia (BNR). There were no differences between the wild type tomato 76R and rmc in the speed or extent to which these fungi infected roots or caused disease. Infection by R. solani induced high levels of defence-related gene expression in both tomato genotypes relative to non-infected plants. In contrast, with BNR the expression of these genes was not induced or induced to a much lower extent than with R. solani. The expression of defence-related genes with these two non-AM fungi was very similar in the two plant genotypes. It was different from effects observed during colonisation by AM fungi, which enhanced expression of defence-related genes in rmc compared with the wild type tomato. The specificity and molecular mechanisms of rmc in control of AM colonisation are discussed.

Impact of an arbuscular mycorrhizal fungus on the growth and nutrition of fifteen crop and pasture plant species

2019 ◽  
Vol 46 (8) ◽  
pp. 732 ◽  
Author(s):  
Binh T. T. Tran ◽  
Stephanie J. Watts-Williams ◽  
Timothy R. Cavagnaro
Keyword(s):  
Plant Species ◽  
Mycorrhizal Fungus ◽  
Agricultural Practices ◽  
Arbuscular Mycorrhizal ◽  
Growth Conditions ◽  
Arbuscular Mycorrhizas ◽  
Allium Ampeloprasum ◽  
Mycorrhizal Colonisation ◽  
Pasture Plant ◽  
Diverse Plant Species

The formation of arbuscular mycorrhizas (AM) can result in positive, neutral or negative responses in the growth and mineral nutrition of host plants, particularly that of P, Zn and other micronutrients. This study examined the growth and nutritional responses of 15 agriculturally important plant species, including cereals, legumes and vegetables, with and without inoculation with the AM fungus (AMF) Rhizophagus irregularis. Furthermore, we explored whether the responses differed between different functional groups of plants such as monocots and dicots, C3 and C4 plants, and N-fixing and non-N-fixing plants. We found that that mycorrhizal colonisation of roots, plant growth and plant nutrient responses differed between plant species. Among the species analysed, leek (Allium ampeloprasum L. var. porrum) was the most mycorrhiza-responsive, displaying the highest mycorrhizal colonisation and biomass response, and the greatest increases in most mineral nutrients. In other plant species, the concentration of P, Cu, Zn and S were generally enhanced by inoculation with AMF. Furthermore, ionomes differed more greatly between plant species than in response to inoculation with AMF. This research further improves our understanding of the responses of different and diverse plant species to the formation of AM in terms of growth and ionomics under standardised growth conditions. The results of this study may be used in further studies and to inform agricultural practices.

Anatomy and ultrastructure of a Rhododendron root–fungus association

1980 ◽  
Vol 58 (23) ◽  
pp. 2421-2433 ◽  
Author(s):  
T. A. Peterson ◽  
W. C. Mueller ◽  
L. Englander
Keyword(s):  
Fungal Infection ◽  
Secondary Growth ◽  
Cortical Layer ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cytoplasm ◽  
Hair Roots ◽  
Short Period ◽  
Infected Cells ◽  
Hyphal Coils

Light and electron microscopic investigations of the roots of Rhododendron and other ericaceous plants growing in the vicinity of Clavaria fruiting structures showed a fungal infection consistently associated with the epidermal and cortical cells of the "hair roots." Uninfected hair roots consisted of an epidermis and a one cell thick cortical layer surrounding the stele. Secondary growth in the stele and formation of a cork layer by division of the pericycle caused the cortex and epidermis to slough as the root matured. The structure of the infected hair roots was similar except for the presence of fungus in epidermal and cortical cells. As judged by the appearance of septa, at least two fungi were involved, one with dolipore septa that formed hyphal coils in the infected cells, and one with septa associated with Woronin bodies that occurred as single hyphal strands. Hyphae were found penetrating the cells from the exterior of the root and also passing from cell to cell. No correlation between fungal infection and the phenolic content of the cells could be made. Dissolution of both the fungal and host cytoplasm appeared to occur as the cells were sloughed. It appears that the fungus–root relationship is complex and is limited in duration to a short period of time during the development of the hair roots.

scholarly journals Phosphorus nutrition of ectomycorrhizal and arbuscular mycorrhizal tree seedlings from a lowland tropical rain forest in Korup National Park, Cameroon

1998 ◽  
Vol 14 (1) ◽  
pp. 47-61 ◽  
Author(s):  
BERNARD MOYERSOEN ◽  
IAN J. ALEXANDER ◽  
ALASTAIR H. FITTER
Keyword(s):  
National Park ◽  
Growth Promotion ◽  
Phosphorus Uptake ◽  
Arbuscular Mycorrhizal ◽  
Arbuscular Mycorrhizas ◽  
Phosphorus Availability ◽  
Tropical Rain Forests ◽  
High Phosphorus ◽  
Korup National Park ◽  
Mycorrhizal Colonisation

The relationship between mycorrhizal colonisation and phosphorus acquired by seedlings of the arbuscular mycorrhizal tree Oubanguia alata Bak f. (Scytopetalaceae) and the ectomycorrhizal tree Tetraberlinia moreliana Aubr. (Caesalpiniodeae) was evaluated at low and high inorganic phosphorus availability. AM colonisation was positively correlated with phosphorus uptake by O. alata at low, but not at high phosphorus availability. Seedlings growth was positively related to arbuscular mycorrhizal colonisation at both low and high phosphorus availability, suggesting that growth promotion by arbuscular mycorrhizas is not simply related to an increase of phosphorus uptake. In contrast, phosphorus uptake by T. moreliana was correlated with EM colonisation at both low and high phosphorus availability, but there was no relationship between growth and ectomycorrhizal colonisation. Promotion of phosphorus uptake by arbuscular mycorrhizas and ectomycorrhizas at low phosphorus availability is consistent with the co-occurrence of the two types of mycorrhiza in tropical rain forests where available soil phosphorus is low. However, ectomycorrhizal colonisation may also be of advantage where inputs of phosphorus rich litter raise the phosphorus status of the soil, as seen in the groves of ectomycorrhizal trees in Korup National Park, and may be one of the factors reinforcing local dominance by these trees.

scholarly journals Modulations in Gene Expression and Mapping of Genes Associated with Cyst Nematode Infection of Soybean

2001 ◽  
Vol 14 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Zarir Vaghchhipawala ◽  
Ronald Bassüner ◽  
Kathryn Clayton ◽  
Kimberley Lewers ◽  
Randy Shoemaker ◽  
...  
Keyword(s):  
Gene Expression ◽  
Soybean Cyst Nematode ◽  
Genetic System ◽  
Cyst Nematode ◽  
Infection Process ◽  
Resistance Locus ◽  
Root Cells ◽  
Feeding Site ◽  
Susceptible Line ◽  
Scn Resistance

Infection of the soybean root by the soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) induces a well-documented, yet poorly understood, response by the host plant. The plant response, involving the differentiation of a feeding structure, or “syncytium,” facilitates the feeding and reproduction of the nematode to the detriment of the host. We used a genetic system involving a single dominant soybean gene conferring susceptibility to an inbred nematode strain, VL1, to characterize the nematode-host interaction in susceptible line PI 89008. The restriction fragment length polymorphism marker pB053, shown to map to a major SCN resistance locus, cosegregates with resistance among F2 progeny from the PI 89008 × PI 88287 cross. Cytological examination of the infection process confirmed that syncytium development in this genetic system is similar to that reported by others who used noninbred nematode lines. Our study of infected root tissue in the susceptible line PI 89008 revealed a number of genes enhanced in expression. Among these are catalase, cyclin, elongation factor 1α, β-1,3-endoglucanase, hydroxymethylglutaryl coenzyme A reductase, heat shock protein 70, late embryonic abundant protein 14, and formylglycinamidine ribonucleotide synthase, all of which we have genetically positioned on the public linkage map of soybean. Formylglycinamidine ribonucleotide synthase was found to be tightly linked with a major quantitative trait locus for SCN resistance. Our observations are consistent with the hypothesis proposed by others that feeding site development involves the dramatic modulation of gene expression relative to surrounding root cells.

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