Quantifying the growth of arbuscular mycorrhizal fungi: usefulness of the fractal dimension

Botany ◽  
2009 ◽  
Vol 87 (4) ◽  
pp. 387-400 ◽  
Author(s):  
Christine Juge ◽  
Annie Champagne ◽  
Andrew P. Coughlan ◽  
Nicolas Juge ◽  
Lael Parrott ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Mycorrhizal Fungi ◽  
Growth And Development ◽  
Time Course ◽  
Glomus Intraradices ◽  
Fungal Growth ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
Growth Cycle

The present study is, to the best of our knowledge, the first to investigate the use of the fractal dimension (FD) to quantify the growth and development of undisturbed, fully functional arbuscular mycorrhizal (AM) hyphae developing in vitro. The majority of the work focused on the model AM fungus Glomus intraradices DAOM 181602. The time course study and final measurements of an intact mature extraradical mycelium allowed us to compare the development of the mycelium and the FD value. The final FD value of 1.62 for the mature mycelium is similar to that obtained for highly branched root systems and tree crowns. The FD method was used to characterize the morphology of germinative and presymbiotic hyphae in the presence of stimulatory (strigolactone GR-24, 0.1 µmol·L–1 and bisphenol A, 10 µmol·L–1) and inhibitory (NaCl, 80 mmol·L–1) molecules, and the extraradical phase in the presence of an inhibitory molecule (NaCl, 80 mmol·L–1). Where possible, results were compared with those obtained using the traditional grid-line (GL) technique. The FD approach allowed treatment effects to be accurately quantified, both in germinative and extraradical phases. In the second case, this technique provided a single quantitative value of extraradical hyphal growth that included runner hyphae (RH) networks, and fine-branching (FB) ramifications. This is in contrast to the GL technique, which provides a value for the estimation of RH, but which is not suitable for accurately measuring FB hyphae. Given the ease with which the FD values can be calculated, and the fact that this method can provide a single value for the quantification of extraradical hyphal growth and development, we suggest that this method is useful for in vitro studies. Furthermore under certain situations of germinative or presymbiotic growth, it may be used in concert with the GL method to provide a greater degree of information about hyphal morphology. The usefulness and limits of the FD method at different stages of the AM fungal growth cycle are discussed.

scholarly journals Effect of Citrus Juice Pomace Extracts on in vitro Hyphal Growth of Vesicular-Arbuscular Mycorrhizal Fungi and their in vivo Infections of Citrus Roots.

2000 ◽  
Vol 69 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Takaaki Ishii ◽  
Jiro Aikawa ◽  
Naoki Nakamura ◽  
Kazuo Sano ◽  
Isao Matsumoto ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
Vesicular Arbuscular Mycorrhizal Fungi ◽  
Citrus Juice ◽  
Vesicular Arbuscular

Variation in in vitro hatch of potato cyst nematodes in response to different potato cultivars inoculated with isolates of arbuscular mycorrhizal fungi

Nematology ◽  
2011 ◽  
Vol 13 (6) ◽  
pp. 661-672
Author(s):  
Patrick Haydock ◽  
Peter Jones ◽  
Thomas Deliopoulos
Keyword(s):  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Arbuscular Mycorrhizal ◽  
Potato Cultivars ◽  
Globodera Pallida ◽  
Cyst Nematodes ◽  
Commercial Mixture ◽  
The Individual ◽  
Shoot Emergence

AbstractSix potato (Solanum tuberosum) cultivars (Home Guard, Bintje, British Queen, Maris Piper, Pentland Dell and Saturna) were inoculated with Vaminoc (a commercial mixture of three selected arbuscular mycorrhizal fungal (AMF) isolates) and with two of the individual AMF isolates present in Vaminoc, Glomus intraradices (BioRize BB-E) and Glomus mosseae (isolate BEG 12). Root length colonisation by AMF at 6 weeks after shoot emergence ranged from 49 to 54%, with Vaminoc exhibiting the highest percentage. In comparison with control plants, AMF-inoculated plants accelerated the in vitro hatch (21% mean increase) of the potato cyst nematode (PCN) species Globodera pallida (but not of G. rostochiensis) in potato root leachate collected 3 weeks after shoot emergence. The effects of mycorrhization on PCN hatch were broadly similar across the six potato cultivars. This consistency supports the potential use of AMF inoculation of potato plants as part of an integrated pest management strategy for G. pallida.

scholarly journals Towards Growth of Arbuscular Mycorrhizal Fungi Independent of a Plant Host

2002 ◽  
Vol 68 (4) ◽  
pp. 1919-1924 ◽  
Author(s):  
Ulrich Hildebrandt ◽  
Katharina Janetta ◽  
Hermann Bothe
Keyword(s):  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Fungal Growth ◽  
Arbuscular Mycorrhizal ◽  
Plant Host ◽  
Significant Step ◽  
Hyphal Coils ◽  
K 12 ◽  
Root Tissues

ABSTRACT When surface-sterilized spores of the arbuscular mycorrhizal fungus (AMF) Glomus intraradices Sy167 were germinated on agar plates in the slightly modified minimum mineral medium described by G. Bécard and J. A. Fortin (New Phytol. 108:211-218, 1988), slime-forming bacteria, identified as Paenibacillus validus, frequently grew up. These bacteria were able to support growth of the fungus on the agar plates. In the presence of P. validus, hyphae branched profusely and formed coiled structures. These were much more densely packed than the so-called arbuscule-like structures which are formed by AMF grown in coculture with carrot roots transformed with T-DNA from Agrobacterium rhizogenes. The presence of P. validus alone also enabled G. intraradices to form new spores, mainly at the densely packed hyphal coils. The new spores were not as abundant as and were smaller than those formed by AMF in the monoxenic culture with carrot root tissues, but they also contained lipid droplets and a large number of nuclei. In these experiments P. validus could not be replaced by bacteria such as Escherichia coli K-12 or Azospirillum brasilense Sp7. Although no conditions under which the daughter spores regerminate and colonize plants have been found yet, and no factor(s) from P. validus which stimulates fungal growth has been identified, the present findings might be a significant step forward toward growth of AMF independent of any plant host.

The effect of flavones and flavonols on colonization of tomato plants by arbuscular mycorrhizal fungi of the genera Gigaspora and Glomus

2007 ◽  
Vol 53 (6) ◽  
pp. 702-709 ◽  
Author(s):  
Jose M. Scervino ◽  
María A. Ponce ◽  
Rosa Erra-Bassells ◽  
Josefina Bompadre ◽  
Horst Vierheilig ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Root Colonization ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
Tomato Plants ◽  
Entry Points ◽  
Chemical Groups ◽  
Positive Effect

No clear data are available on how flavonoids from different chemical groups affect root colonization by arbuscular mycorrhizal fungi (AMF) and whether flavonoids affecting the presymbiotic growth of AMF also affect root colonization by AMF. In the present work, we compared the effect of flavones (chrysin and luteolin) and flavonols (kaempferol, morin, isorhamnetin, and rutin) on root colonization (number of entry points and degree of root colonization) of tomato plants ( Lycopersicum esculentum L.) with the effect of these flavonoids on the presymbiotic growth of these AMF, which has been reported in a recent study. With all tested AMF ( Gigaspora rosea , Gigaspora margarita , Glomus mosseae, and Glomus intraradices) a correlation between the number of entry points and the percentage of root colonization was found. When the number of entry points was high, root colonization was also enhanced. Application of the flavones chrysin and luteolin and of the flavonol morin increased the number of entry points and the degree of colonization,whereas the flavonols kaempferol, isorhamnetin, and rutin showed no effect. These results show that in contrast to their effect on the presymbiotic growth of the AMF on the level of root colonization, the tested flavonoids do not exhibit a genus- and species-specificity. Moreover, comparison of our data with the data obtained by J.M. Scervino, M.A. Ponce, R. Erra-Bassells, H. Vierheilig, J.A. Ocampo, and A. Godeas. (2005a. J. Plant Interact. 15: 22–30) indicates that a positive effect on the hyphal growth of AMF does not necessarily result in an enhanced AM root colonization, further indicating that the mode of action of flavonoids at the level of root colonization is more complex.

scholarly journals Mycorrhiza-induced Changes in Partitioning and Composition Alters Flower and Vegetative Production of Floral Geophytes

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 767C-767
Author(s):  
Carolyn Scagel*
Keyword(s):  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Arbuscular Mycorrhizal ◽  
Growth Cycle ◽  
Flower Production ◽  
Freesia Hybrida ◽  
Resource Storage ◽  
Induced Changes ◽  
Amf Inoculation

Resource partitioning and plant storage components are important factors that influence the productivity and profitability of geophyte species produced as floral crops. We determined that inoculation with arbuscular mycorrhizal fungi (AMF) can alter different plant characteristics affecting productivity and quality of bulb and cut flower production of several floral geophytes including Brodiaea laxa, Zephyranthes sp., Sparaxis tricolor, Freesia × hybrida, Zantedeschia sp., and Canna sp. Plant growth, flower production, bulb/corm/tuber (bulb) production and composition were measured for two growth cycles after inoculation with Glomus intraradices. In general, shoots and flowers on plants inoculated with AMF emerged earlier than shoots and flowers on non-inoculated plants for species that produced most of their leaf area prior to flower emergence. However for species that produced leaves throughout the growth cycle or large flowers early in the growth cycle, AMF inoculation delayed shoot emergence and flower emergence. Many species that exhibited an earlier flower emergence or produced more flowers in response to AMF inoculation also produced smaller daughter bulbs and more offsets than non-inoculated plants. Across all species, the concentrations and contents of several storage components (Zn, S, and N, amino acids, and carbohydrates) that influence bulb quality were increased by AMF inoculation. Changes in partitioning between bulb and flower production resulting from AMF inoculation altered important aspects of commercial geophyte production for flowers or bulbs. AMF-induced increases in mineral uptake and resource storage are also related to aspects of quality important in the production of vegetative propagates.

scholarly journals Effect of arbuscular mycorrhiza on the growth and development of micropropagated Annona cherimola plants

1994 ◽  
Vol 3 (3) ◽  
pp. 281-288 ◽  
Author(s):  
Concepcion Azcón-Aguilar ◽  
C.L. Encina ◽  
R. Azcón ◽  
Jose Miguel Barea
Keyword(s):  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Growth And Development ◽  
Clonal Selection ◽  
Arbuscular Mycorrhizal ◽  
Optimal Growth ◽  
Annona Cherimola ◽  
Survival And Development ◽  
Acclimatization Period

Annona cherimola Mill., cherimoya, is a tropical plantation crop of interest in fruit culture. Micropropagation techniques have been developed due to the need to increase productivity through clonal selection. Because of the mycorrhizal dependence exhibited by this crop for optimal growth and the recognized role of mycorrhiza establishment for the survival and development of most of the plants produced in vitro, the effect of mycorrhiza inoculation on the development of micropropagated plants of Annona cherimola was investigated. Mycorrhizal inoculation was assayed at two different stages of the micropropagation process: (i) immediately after the in vitro phase, before starting the acclimatization period, and (ii) after the acclimatization phase, before starting the post-acclimatization period under greenhouse conditions. Plantlet survival was about 50 % after the acclimatization period. Plant growth and development profited remarkably from mycorrhiza establishment. Most of the arbuscular mycorrhizal fungi (AMF) assayed greatly increased shoot and root biomass and leaf area. Micropropagated Annona plants seem to be more dependent on mycorrhiza formation for optimal growth than plants derived from seeds. The greatest effects of AMF on plant growth were observed when they were introduced after the acclimatization period.

Using Flavonoids to Control in vitro Development of Vesicular Arbuscular Mycorrhizal Fungi

1995 ◽  
Author(s):  
Donald Phillips ◽  
Yoram Kapulnik
Keyword(s):  
Host Plant ◽  
Spore Germination ◽  
Mycorrhizal Fungi ◽  
Field Experiments ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
In Vitro Production ◽  
Vam Fungi ◽  
Vesicular Arbuscular

Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions

scholarly journals Isolation of a Premycorrhizal Infection (pmi2) Mutant of Tomato, Resistant to Arbuscular Mycorrhizal Fungal Colonization

2003 ◽  
Vol 16 (5) ◽  
pp. 382-388 ◽  
Author(s):  
Rakefet David-Schwartz ◽  
Vijay Gadkar ◽  
Smadar Wininger ◽  
Roza Bendov ◽  
Gad Galili ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Glomus Intraradices ◽  
Arbuscular Mycorrhizal ◽  
Plant Roots ◽  
Fungal Colonization ◽  
Recessive Trait ◽  
Wild Type ◽  
Arbuscular Mycorrhizal Fungal

Arbuscular mycorrhizae (AM) represent an ancient symbiosis between mycorrhizal fungi and plant roots which co-evolved to exhibit a finely tuned, multistage interaction that assists plant growth. Direct screening efforts for Myc¯ plant mutants resulted in the identification of a tomato (Lycopersicon esculentum L. cv. Micro-Tom) mutant, M20, which was impaired in its ability to support the premycorrhizal infection (pmi) stages. The Myc¯ phenotype of the M20 mutant was a single Mendelian recessive trait, stable for nine generations, and nonallelic to a previously identified M161 pmi mutant. The M20 mutant was resistant to infection by isolated AM spores and colonized roots. Formation of Glomus intraradices appressoria on M20 roots was normal, as on wild-type (WT) plants, but in significantly reduced numbers. A significant reduction in spore germination was observed in vitro in the presence of M20 exudates relative to WT. Our results indicate that this new mutant shares similar physiological characteristics with the M161 pmi mutant, but has a more suppressive Myc¯ phenotype response.

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