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1.
Interactions between the mycorrhizal fungus Glomus monosporum and the root rot pathogen Thielaviopsis basicola and their effects on tobacco plants were investigated over a 4 week period. Mycorrhizal tobacco plants, obtained by preinoculation with G. monosporum, showed a better tolerance to T. basicola than non-mycorrhizal seedlings. Root and leaf dry weights of mycorrhizal plants were greater than those of controls. Mycorrhizal plants inoculated with T. basicola showed higher root and leaf dry weights than non-mycorrhizal infected plants, but lower values than mycorrhizal plants which were not infected. No appreciable differences in free aminoacid composition were observed among the different treatments with two exceptions: proline content was higher in infected and mycorrhizal infected plants compared to control and mycorrhizal plants; arginine content was higher in infected and mycorrhizal infected plants compared to control and mycorrhizal plants; arginine content was higher in mycorrhizal plants than in all the other treatments. The mechanisms by which (VAM) fungi can reduce disease incidence and pathogen development are discussed. 相似文献
2.
Iron Bound-Siderophores, Cyanic Acid, and Antibiotics Involved in Suppression of Thielaviopsis basicola by a Pseudomonas fluorescens Strain 总被引:1,自引:0,他引:1
A Pseudomonas fluorescens strain (CHAo) involved in suppression of black root rot caused by Thielaviopsis basicola in the field, inhibited T. basicola when colonizing roots grown under sterile conditions or when grown on culture, media. Under these conditions it produced siderophores (iron chelating compounds), cyanic acid, and several antibiotics. Iron-free siderophores inhibited neither the germination of endoconidia or chlamydospores nor the mycelial growth of T. basicola, but reduced the production of endoconidia. On the contrary, siderophores complexed with Fe3+ strongly inhibited mycelium growth and spore germination; free iron was less toxic than iron-bound siderophores. Therefore, contrary to what was believed to date, siderophores seem to be toxic not because they deplete iron but because they increase its concentration to the point where it becomes highly toxic. Cyanic acid and the antibiotics also inhibited the growth of T. basicola. Whetherall these compounds are involved in disease control in the soil remains, however, to be determined. 相似文献
3.
Effects of soil pH and nitrogen fertility on the population dynamics of Thielaviopsis basicola 总被引:1,自引:0,他引:1
Black root rot of tobacco, caused by Thielaviopsis basicola, is generally severe at soil pH values >5.6 and suppressed under more acidic conditions (pH < 5.2). Soil acidifying fertilizers containing NH4–N are generally recommended for burley tobacco production in North Carolina, but the effects of N form and application rate on development of black root rot and on the population dynamics of T. basicola have not been determined. Greenhouse and laboratory studies were conducted to evaluate the effects of N form (NH4
+ or NO3
–) and rate on pathogen and disease parameters at several initial soil pH levels. A moderately-conducive field soil, initial pH 4.7, was adjusted to a pH of 5.5 or 6.5 by the addition of CaOH2, then amended with the desired nitrogen form and rate. Pathogen populations were determined over time. In addition, spore production in extracts of roots from plants grown in the various nitrogen and pH treatments was determined. Finally, because tobacco responds to acidic soil conditions and exposure to NH4–N by accumulating high concentrations of the polyamine putrescine, the toxicity of putrescine on vegetative growth and reproduction of T. basicola was investigated. Low soil pH and high levels of NH4–N suppressed reproduction of T. basicola in soil and in root extract, while use of NO3–N and depletion of NH4–N resulted in rapid increases in populations of T. basicola. At 20 mM, putrescine inhibited hyphal growth by 60% and aleuriospore production by 98%. Fertilizers that reduced soil pH also reduced reproduction by T. basicola, and thus have potential for management of black root rot by suppressing populations of T. basicola over multiple years of crop production. The suppression of T. basicola and black root rot observed with NH4–N amendments may partially be due to development of an inhibitory environment in the root and not solely to changes in rhizosphere pH. 相似文献
4.
Mycorrhizal infection,phosphorus uptake,and phenology in Ranunculus adoneus: implications for the functioning of mycorrhizae in alpine systems 总被引:3,自引:0,他引:3
Phosphorus levels, phenology of roots and shoots, and development of vesicular arbuscular mycorrhizal (VAM) fungi were monitored for two years in natural populations of the perennial alpine herb, Ranunculus adoneus. The purpose of this study was to understand how phosphorus uptake relates to the phenology of R. adoneus and to ascertain whether arbusculus, fungal structures used for nutrient transfer, were present when maximum phosphorus accumulation was occurring. Arbuscules were only present for a few weeks during the growing season of R. adoneus and their presence corresponded with increased phosphorus accumulation in both the roots and shoots of R. adoneus. In addition, phosphorus accumulation and peaks in mycorrhizal development occurred well after plant reproduction and most plant growth had occurred. The late season accumulation of phosphorus by mycorrhizal roots of R. adoneus is stored for use during early season growth and flowering the following spring. In this way R. adoneus can flower before soils thaw and root or mycorrhizal nutrient uptake can occur. 相似文献
5.
MARIA M. GELDENHUIS JOLANDA ROUX MICHAEL J. WINGFIELD BRENDA D. WINGFIELD 《Molecular ecology resources》2004,4(4):547-550
Thielaviopsis basicola is a soil‐borne fungal pathogen affecting many important agricultural crops. Little is known regarding the population biology or origin of this pathogen. Polymorphic markers developed for Ceratocystis fimbriata, a species complex phylogenetically closely related to T. basicola, were tested and found not to be useful for T. basicola. In this study 14 primer pairs, seven of which resulted in the amplification of single polymorphic fragments in T. basicola were developed. These primers will enable further studies on this economically important pathogen, and will result in an enhanced understanding of its population structure in different parts of the world. 相似文献
6.
Genuine roots ofSpiranthes sinensis var.amoena were infected with the mycorrhizal fungusRhizoctonia repens immediately after root formation in autumn. Infection by the mycorrhizal fungus extended, reaching a maximum the following
early summer. The amount of living mycorrhizal fungus in the genuine roots dramatically declined in the flowering season,
and then the roots decomposed. Tuberous roots were formed in spring. Mycorrhizas were limited to local infections and did
not spread along the roots. The infection level of living mycorrhizal fungus in the tuberous roots was less than in the genuine
roots throughout the year. The amount of dead fungal coils in the tuberous roots increased as the tuberous roots aged. The
mycorrhizal characteritics of tuberous roots ofS. sinensis var.amoena were totally different from those of genuine roots although the tuberous roots morphologically resembled the genuine roots.
Contribution No. 96, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba. 相似文献
7.
The hypothesis that Thielaviopsis basicola might be the causal agent of the specific replant disorders of cherry and plum was tested in experiments with pot-grown trees and by observations on the distribution of the pathogen. The results obtained with certain strains of T. basicola simulated and were consistent with all features known to characterize the specific replant disorders, viz. inter- and intra-generic specificity of effect; host symptoms; establishment, immobility and persistence of the causal agent in soil; normal growth of affected trees after transfer to ‘non-replant’ soil; limited influence of soil type on the incidence of the disorder. T. basicola was therefore considered to be the probable causal agent of the specific replant diseases of certain Prunus species. The etiology of these diseases is discussed. T. basicola was neither pathogenic to apple nor associated with the growth of apple. The apparently closely similar specific replant disorder of Malus is therefore considered to be causally distinct from those of cherry and plum. 相似文献
8.
Thassilo Franke Ludwig Beenken Matthias Döring Alexander Kocyan Reinhard Agerer 《Mycological Progress》2006,5(1):24-31
We amplified and sequenced partial 18S rDNA of fungi in the roots of 11 African myco-heterotrophic plants out of four angiosperm families (Burmanniaceae, Thismiaceae, Triuridaceae, and Gentianaceae). The sequences were cladistically analyzed with published sequences of arbuscular mycorrhizal fungi. We show that all investigated African myco-heterotrophic plants are associated with arbuscular mycorrhizal fungi within a clade of Glomus (Glomus-group A). We reveal a fine-level mycorrhizal specificity for a particular set of arbuscular mycorrhizal fungi within Glomus-group A by Afrothismia hydra (Thismiaceae). Furthermore, we show that the roots of two myco-heterotrophic plant individuals, besides being colonized by representatives of Glomus-group A, also contain DNA of Acaulospora sp. Consequently, Acaulospora is interpreted as a facultative mycorrhizal associate. 相似文献
9.
Joëlle V. F. Coumans Pierre D. J. Moens Anne Poljak Samiya Al‐Jaaidi Lily Pereg Mark J. Raftery 《Proteomics》2010,10(8):1573-1591
Thielaviopsis basicola is a hemibiotroph fungus that causes black root rot disease in diverse plants with significant impact on cotton production in Australia. To elucidate how T. basicola growth and proteome are influenced by interactions with natural sources, this fungus was cultured in the presence of root extracts from non‐host (wheat, hairy vetch) and susceptible host (cotton, lupin) plants. We found that T. basicola growth was significantly favored in the presence of host extracts, while hierarchical clustering analysis of 2‐DE protein profiles of T. basicola showed plant species had a larger effect on the proteome than host/non‐host status. Analysis by LC‐MS/MS of unique and differentially expressed spots and identification using cross‐species similarity searching and de novo sequencing allowed successful identification of 41 spots. These proteins were principally involved in primary metabolism with smaller numbers implicated in other diverse functions. Identification of several “morpho” proteins suggested morphological differences that were further microscopically investigated. Identification of several highly expressed spots suggested that vitamin B6 is important in the T. basicola response to components present in hairy vetch extract, and finally, three spots, induced in the presence of lupin extract, may correspond to malic enzyme and be involved in lipid accumulation. 相似文献
10.
A morphological and anatomical study of the root systems of the palm species Brahea armata S. Watson, Chamaerops humilis L., Phoenix canariensis Chabaud and Phoenix dactylifera L. has been carried out to determine possible mycorrhizal colonization sites. Furthermore, the arbuscular mycorrhizal (AM)
anatomical types formed by the four palm species in association with Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe have been examined. The presence of a continuous sclerenchymatic ring in the outer cortex
and aerenchyma in the inner cortex that are anatomical indicators of mycorrhizal nonsusceptibility in all four palm species
is observed. The root systems of B. armata and C. humilis present only one group of third-order roots, while the third-order roots of P. canariensis and P. dactylifera may be divided into five different groups: short thick roots, mycorrhizal thickened roots, fine short roots, fine long roots,
and pneumatorhizas. Third-order and some second-order roots of B. armata and C. humilis are susceptible to colonization by AM fungi, while only the mycorrhizal thickened roots form mycorrhizas with arbuscules
in the Phoenix species. The root system of the Phoenix species also presents AM colonization in fine roots with only intraradical hyphae and spores, but without arbuscules, and
pseudomantles of spores anchored in the pneumatorings of the second-order roots, which are described for the first time. The
mycorrhizas formed by the four palm species are of an intermediate type, between the Arum and the Paris types, and are characterized by intercalary arbusculate coils and not only by intracellular but also by intercellular fungal
growth. Our study suggests that a different degree of adaptation may exist among palm mycorrhizas toward the slow growth of
palms and low spore numbers in the soil where they grow. 相似文献
11.
葡萄糖、根浸出液对丛枝菌根真菌吸收不同外源氮产生精氨酸的影响 总被引:1,自引:0,他引:1
以大葱(Allium fistulosum)为宿主植物, 接种丛枝菌根(Arbuscular mycorrhizal, AM)真菌Glomus intraradices, 采用三室隔离盆栽培养系统, 在菌丝室施加浓度为4 mmol/L的不同形态外源氮、1%葡萄糖及根浸出液, 通过测定根外菌丝(Extraradical mycelium, ERM)和菌根中精氨酸的含量, 探究葡萄糖、根浸出液对AM真菌吸收不同形式外源氮产生精氨酸的影响。结果表明, 不同外源氮对ERM中精氨酸含量的影响为尿素>Gln>NH4NO3>Arg/Gly>NH4Cl>KNO3, 对菌根中精氨酸含量的影响为Arg>Gln>尿素>NH4NO3>Gly>NH4Cl>KNO3; 施加葡萄糖和根浸出液在不同程度上提高ERM干重和菌丝室孢子数量, 但使ERM和菌根中的精氨酸含量降低。说明AM真菌吸收同化不同外源氮产生精氨酸的能力不同, 葡萄糖和根浸出液降低AM真菌吸收同化外源氮产精氨酸的能力。 相似文献
12.
Plasma membrane ATPase and H+ transport activities in microsomal membranes from mycorrhizal tomato roots 总被引:4,自引:0,他引:4
ATPase activity, ATP-dependent H+ transport and the
amount of antigenic tomato plasma membrane H+-APTase
have been analysed in membrane vesicles isolated from Glomus
mosseae- or Glomus intraradices-colonized
roots and from non-mycorrhizal tomato roots. Microsomal protein content was
higher in mycorrhizal than in control roots. The specific activity of the
plasma membrane H+-ATPase was not affected by
mycorrhizal colonization, although this activity increased in membranes
isolated from mycorrhizal roots when expressed on a fresh weight basis.
Western blot analysis of microsomal proteins using antibodies raised
against the Arabidopsis thaliana plasma membrane
H+ - ATPase showed that mycorrhizal colonization did
not change the relative amount of tomato plasma membrane ATPase in the
microsomes. However, on a fresh weight basis, there was a greater amount of
this protein in roots of mycorrhizal plants. In addition, mycorrhizal
membranes showed a higher specific activity of the vanadate-sensitive
ATP-dependant H+ transport than membranes isolated
from control roots. These results suggest that mycorrhiza might regulate
the plasma membrane ATPase by increasing the coupling efficiency between
H+ transport and ATP hydrolysis. The observed
effects of mycorrhizal colonization on plasma membrane
H+-ATPase were independent of the AM fungal species
colonizing the root system. 相似文献
13.
The influence of mycorrhizal colonization on beech (Fagus sylvatica L.) root tannin (procyanidin polymer) and its putative precursors catechin and epicatechin was investigated by high performance
liquid chromatography. Seedlings planted in a sterile mixture of litter, compost, soil and sand were inoculated with brown
beech ectomycorrhizas collected from a woodland (Lactarius subdulcis Bull ex Fr. × F. sylvatica). The seedlings were not fertilized during the first year of growth. Nonmycorrhizal control plants showed severe nutrient-deficiency
symptoms on their leaves and grew less well than mycorrhizal plants. Mycorrhizal roots contained significantly less catechin,
epicatechin and procyanidin polymer than nonmycorrhizal roots. In the second year of growth, the plants were fertilized and
procyanidin formation in roots was investigated. None of the fertilized plants showed mineral-deficiency symptoms. Fertilized
mycorrhizal roots consistently contained significantly less catechin and epicatechin than nonmycorrhizal controls, but procyanidin
polymer content varied between replicate experiments. The possible function of catechin and epicatechin in ectomycorrhizal
formation is discussed.
Accepted: 11 July 1997 相似文献
14.
Antoni Werner Anna Napierała-Filipiak Marek Mardarowicz Jan Gawdzik 《Acta Physiologiae Plantarum》2004,26(2):187-196
The effect of two substrates differing in the amount of toxic metals and nutrients on the content of volatile organic compounds
in roots of Pinus sylvestris seedlings inoculated with Paxillus involutus, Laccaria laccata, Suillus luteus and a strain of the ectendomycorrhizal fungus Mrg X (Ascomycotina) in pot experiment was investigated. Volatile compounds extracted with a supercritical fluid extraction were primarily terpenes
and sesquiterpenes, and they were qualitatively the same in roots of mycorrhizal and nonmycorrhizal plants grown on both substrates.
The major monoterpenes were α-pinene, Δ3-carene and β-pinene. On the unpolluted substrate, inoculation of plants with the fungi resulted in a similar amount of the
volatiles, while on the polluted substrate the mycorrhizal roots showed significantly lower content of terpenoids than nonmycorrhizal
roots. The mycorrhizal fungi showed different effects on the concentrations of several terpenoids on both substrates. 相似文献
15.
Bacterial effects on arbuscular mycorrhizal fungi and mycorrhiza development as influenced by the bacteria, fungi, and host plant 总被引:1,自引:0,他引:1
Pivato B Offre P Marchelli S Barbonaglia B Mougel C Lemanceau P Berta G 《Mycorrhiza》2009,19(2):81-90
Bacterial strains from mycorrhizal roots (three belonging to Comamonadaceae and one to Oxalobacteraceae) and from non-mycorrhizal roots (two belonging to Comamonadaceae) of Medicago truncatula and two reference strains (Collimonas fungivorans Ter331 and Pseudomonas fluorescens C7R12) were tested for their effect on the in vitro saprophytic growth of Glomus mosseae BEG12 and on its colonization of M. truncatula roots. Only the Oxalobacteraceae strain, isolated from barrel medic mycorrhizal roots, and the reference strain P. fluorescens C7R12 promoted both the saprophytic growth and root colonization of G. mosseae BEG12, indicating that they acted as mycorrhiza helper bacteria. Greatest effects were achieved by P. fluorescens C7R12 and its influence on the saprophytic growth of G. mosseae was compared to that on Gigaspora rosea BEG9 to determine if the bacterial stimulation was fungal specific. This fungal specificity, together with plant specificity,
was finally evaluated by comparing bacterial effects on arbuscular mycorrhizal symbiosis when each of the fungal species was
inoculated to two different plant species (M. truncatula and Lycopersicon esculentum). The results obtained showed that promotion of saprophytic growth by P. fluorescens C7R12 was expressed in vitro towards G. mosseae but not towards G. rosea. Bacterial promotion of mycorhization was also expressed towards G. mosseae, but not G. rosea, in roots of M. truncatula and L. esculentum. Taken together, results indicated that enhancement of arbuscular mycorrhiza development was only induced by a limited number
of bacteria, promotion by the most efficient bacterial strain being fungal and not plant specific. 相似文献
16.
Arbuscular Mycorrhizal Assemblages in Native Plant Roots Change in the Presence of Invasive Exotic Grasses 总被引:2,自引:0,他引:2
Christine V. Hawkes Jayne Belnap Carla D’Antonio Mary K. Firestone 《Plant and Soil》2006,281(1-2):369-380
Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground
effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site
in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic
(Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing.
We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant
roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the
number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the
mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil
that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration
of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects
of invaders on the ecosystem. 相似文献
17.
E. Dumas-Gaudot P. Guillaume A. Tahiri-Alaoui V. Gianinazzi-Pearson S. Gianinazzi 《Mycorrhiza》1994,4(5):215-221
Changes in gene expression were studied during the establishment of arbuscular mycorrhizal symbiosis in tobacco roots from an amphidiploid hybrid Nicotiana glutinosa x N. debneyi. Polypeptide patterns from control roots and from roots infected by Glomus mosseae or G. intraradices were resolved by two-dimensional polyacrylamide gel electrophoresis and followed in a time-course analysis. Arbuscular mycorrhizal infection led to significant modifications in polypeptide patterns with: (a) decreased amounts of some polypeptides, (b) increased accumulation of others, and (c) appearance of newly-induced polypeptides. Comparisons made during infection development by the two Glomus species demonstrated that protein modifications changed in relation to the mycorrhizal state of the tobacco roots. 相似文献
18.
A. Martins Margarida Santos Helena Santos Maria Salomé Pais 《Trees - Structure and Function》1999,13(3):168-172
31P-Nuclear Magnetic Resonance (NMR) was used to assess phosphate distribution in ectomycorrhizal and nonmycorrhizal roots of
Castanea sativa Mill. as well as in the mycorrhizal fungus Pisolithus tinctorius in order to gain insight into phosphate trafficking in these systems. The fungus P. tinctorius accumulated high levels of polyphosphates during the rapid phase of growth. Mycorrhizal and nonmycorrhizal roots accumulate
orthophosphate. Only mycorrhizal roots presented polyphosphates. The content in polyphosphates increased along the 3 months
of mycorrhiza formation. In mycorrhizal roots of plants cultured under axenic conditions, the orthophosphate pool decreased
along the culture time. In nonmycorrhizal roots the decrease in the orthophosphate content was less pronounced. The level
of orthophosphate in mycorrhizal roots was significantly lower than in nonmycorrhizal ones, which indicates that this system
relies upon the fungal polyphosphates as a major source of phosphate.
Received: 28 July 1998 / Accepted: 21 October 1998 相似文献
19.
Walter Maier Jürgen Schmidt Victor Wray Michael Herbert Walter Dieter Strack 《Planta》1999,207(4):620-623
Tobacco (Nicotiana tabacum L.) plants were grown with and without the arbuscular mycorrhizal fungus, Glomus intraradices Schenk & Smith. High-performance liquid chromatographic analyses of methanolic extracts from mycorrhizal and non-mycorrhizal
tobacco roots revealed marked fungus-induced changes in the patterns of UV-detectable products. The UV spectra of these products,
obtained from an HPLC photodiode array detector, indicated the presence of several blumenol derivatives. The most predominant
compound among these derivatives was spectroscopically identified as 13-hydroxyblumenol C 9-O-gentiobioside (“nicoblumin”), i.e. the 9-O-(6′-O-β-glucopyranosyl)-β-glucopyranoside of 13-hydroxy-6-(3-hydroxybutyl)-1,1,5-trimethyl-4-cyclohexen-3-one, a new natural product.
This is the first report on the identification of blumenol derivatives in mycorrhizal roots of a non-gramineous plant.
Received: 28 August 1998 / Accepted: 26 October 1998 相似文献
20.
Pietro Spanu Thomas Boller Alexander Ludwig Andres Wiemken Antonella Faccio Paola Bonfante-Fasolo 《Planta》1989,177(4):447-455
Chitinase (EC 3.2.1.14) activity was measured in roots of Allium prorrum L. (leek) during development of a vesicular-arbuscular mycorrhizal symbiosis with Glomus versiforme (Karst.) Berch. During the early stages of infection, between 10 and 20 d after inoculation, the specific activity of chitinase was higher in mycorrhizal roots than in the uninfected controls. However, 60–90 d after inoculation, when the symbiosis was fully established, the mycorrhizal roots contained much less chitinase than control roots. Chitinase was purified from A. porrum roots. An antiserum against beanleaf chitinase was found to cross-react specifically with chitinase in the extracts from non-mycorrhizal and mycorrhizal A. porrum roots. This antiserum was used for the immunocytochemical localization of the enzyme with fluorescent and gold-labelled probes. Chitinase was localized in the vacuoles and in the extracellular spaces of non-mycorrhizal and mycorrhizal roots. There was no immunolabelling on the fungal cell walls in the intercellular or the intracellular phases. It is concluded that the chitin in the fungal walls is inaccessible to plant chitinase. This casts doubts on the possible involvement of this hydrolase in the development of the mycorrhizal fungus. However, fungal penetration does appear to cause a typical defense response in the first stages that is later depressed. 相似文献