Colonization of Orchis morio protocorms by a mycorrhizal fungus: effects of nitrogen nutrition and glyphosate in modifying the responses

1995 ◽  
Vol 73 (8) ◽  
pp. 1128-1140 ◽  
Author(s):  
H. F. Beyrle ◽  
S. E. Smith ◽  
C. M. M. Franco ◽  
R. L. Peterson
Keyword(s):  
Mycorrhizal Fungi ◽  
Phenylalanine Ammonia Lyase ◽  
Shikimic Acid ◽  
Nitrogen Nutrition ◽  
Mycorrhizal Fungus ◽  
Fungal Growth ◽  
Soft Rot ◽  
Nitrogen Supply ◽  
Wall Thickening ◽  
Low Nitrogen

Effects of nitrogen nutrition and application of glyphosate (as Roundup™) on the interactions between protocorms of Orchis morio and a mycorrhizal Rhizoctonia species were investigated. Protocorms for all experiments were raised clonally in liquid culture. Split plates were used to separate the direct effects of composition of the media from effects mediated via the fungus. Mycorrhizal interactions, including coil formation and prolonged protocorm growth, were established when a relatively low nitrogen supply to the fungus (as NH4)2SO4) was combined with a high carbohydrate supply. Rejection of the fungus, associated with phenolic production, wall thickening, and lack of protocorm growth, was observed with high-carbon, high-nitrogen medium. Low carbohydrate supply, with either high or low nitrogen supply, was associated with breakaway parasitism, symptoms of soft rot, and lack of subsequent protocorm growth. Application of glyphosate at 0.5 or 1.0 mM had no effect on fungal growth and at 1.0 mM did not cause death of asymbiotic protocorms, but resulted in failure of mycorrhizal initiation. Coils were never formed and the fungus ramified through the tissues of the protocorms. The parasitism induced by glyphosate differed from breakaway parasitism, and there were no symptoms of soft rot. Assays for activity of phenylalanine ammonia lyase (PAL) and for orchinol were carried out to assess the effects of the treatments on the shikimic acid pathway. Low activity of PAL and low quantities of orchinol (together with another unidentified phenolic compound) were detected in asymbiotic protocorms. Concentrations of both were increased in the presence of the fungus, but no significant differences were observed in the various symbiotic responses in the absence of glyphosate. This is the first report of the presence of orchinol in orchid protocorms. Previous work has always been carried out on tubers, which are not usually colonized by the mycorrhizal fungi. Application of glyphosate resulted in increases in both PAL activity and orchinol production. The results are discussed in the context of orchid–fungus interactions and the mechanism of glyphosate action. Key words: orchid, mycorrhiza, parasitism, cell walls, glyphosate, phenylalanine ammonia lyase (PAL), orchinol.

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.

scholarly journals (371) Hydroponic Inoculation of Cranberry with Ericoid Mycorrhizal Fungus

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1058D-1058
Author(s):  
Piero A. Spada ◽  
Beth Ann A. Workmaster ◽  
Kevin R. Kosola
Keyword(s):  
Mycorrhizal Fungi ◽  
Nitrogen Nutrition ◽  
Mycorrhizal Fungus ◽  
Nitrogen Sources ◽  
Solution Culture ◽  
Mycorrhizal Colonization ◽  
Ammonium Concentration ◽  
Mycorrhizal Plants ◽  
Almost All ◽  
Ericoid Mycorrhizal Fungus

Cranberry (Vaccinium macrocarpon) plants colonized with ericoid mycorrhizal fungi are capable of utilizing organic nitrogen sources that are unavailable to non-mycorrhizal plants. Despite the importance of mycorrhizal colonization in the nitrogen nutrition of wild cranberry, almost all measurements of cranberry nitrogen uptake and assimilation have been carried out with non-mycorrhizal plants. We have found that cranberry can be inoculated directly in solution culture. We cultured the ericoid mycorrhizal fungus Hymenoscyphusericaein liquid culture, harvested and rinsed hyphae, and added ≈200 mg fresh weight hyphae per rooted cranberry cutting (cv. Stevens) growing in a modified Johnson's solution. After 6 weeks, newly developed roots were most heavily colonized. We examined the effects of NH4+ concentration (5, 10, 20, 50, 100, and 500 μm NH4+) in solution on colonization rates. Colonization (% root length) increased with increasing ammonium concentration in solution, with maximum colonization at 50 and 100 μm NH4+; colonization was much lower at 500 μm NH4+. Cranberry inoculated with H. ericaein solution culture will be used for analysis of the effects of mycorrhizal colonization on uptake kinetics of NH4+, NO3-, and amino acids.

Nitrogen metabolism in durum wheat under salinity: accumulation of proline and glycine betaine

2008 ◽  
Vol 35 (5) ◽  
pp. 412 ◽  
Author(s):  
Petronia Carillo ◽  
Gabriella Mastrolonardo ◽  
Francesco Nacca ◽  
Danila Parisi ◽  
Angelo Verlotta ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Glycine Betaine ◽  
Nitrogen Nutrition ◽  
Compatible Solutes ◽  
Glutamate Synthase ◽  
Nitrogen Supply ◽  
Carbon And Nitrogen ◽  
Young Leaves ◽  
Prolonged Stress ◽  
Low Nitrogen

We studied the effect of salinity on amino acid, proline and glycine betaine accumulation in leaves of different stages of development in durum wheat under high and low nitrogen supply. Our results suggest that protective compounds against salt stress are accumulated in all leaves. The major metabolites are glycine betaine, which preferentially accumulates in younger tissues, and proline, which is found predominantly in older tissues. Proline tended to accumulate early, at the onset of the stress, while glycine betaine accumulation was observed during prolonged stress. Nitrate reductase (NR) and glutamate synthase (GOGAT) are positively correlated with these compatible solutes: proline is associated with NR in the oldest leaves of high-nitrate plants and glycine betaine is associated with GOGAT in the youngest leaves of both low- and high-nitrate plants. In high-nitrate conditions proline accounts for more than 39% of the osmotic adjustment in the cytoplasmic compartments of old leaves. Its nitrogen-dependent accumulation may offer an important advantage in that it can be metabolised to allow reallocation of energy, carbon and nitrogen from the older leaves to the younger tissues. The contribution of glycine betaine is higher in young leaves and is independent of nitrogen nutrition.

scholarly journals The Effect of Mycorrhizal Fungi and PGPR on Tree Nutritional Status and Growth in Organic Apple Production

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1402
Author(s):  
Sebastian Przybyłko ◽  
Wojciech Kowalczyk ◽  
Dariusz Wrona
Keyword(s):  
Nutritional Status ◽  
Mycorrhizal Fungi ◽  
Negative Impact ◽  
Nitrogen Nutrition ◽  
Nutrient Use Efficiency ◽  
Plant Competition ◽  
Fruit Production ◽  
Organic Fertilizers ◽  
Nutrition Status ◽  
Tree Roots

The desire to reduce the negative impact of crops on the environment, as well as the growing concern for consumer health, is increasing interest in organic fruit production. In this context, the development of new environmentally friendly agrotechnical methods which allows for reducing the use of organic fertilizers by improving the nutrient use efficiency and consequently decreasing the leaching of them is a task of a great importance. The main purpose of this study was to evaluate the effect of mycorrhizal arbuscular fungi (AMF) combined with plant-growth-promoting rhizobacteria (PGPR) on growth and nutritional status of apple trees cultivated on a silty-loam, rich in clay minerals and humus soil under organic farming conditions. Thus, a trial was established in an experimental orchard in Wilanów in Central Poland with three cultivars (‘Topaz’, ‘Odra’, and ‘Chopin’) and a promising clone, U 8869. Trees were or were not inoculated with AMF + PGPR within a split-block experimental design with four replicates. According to the results, mycorrhizal frequency obtained in the inoculated tree roots was on average two-fold higher than in the roots of the control plants. After four years of AMF + PGPR inoculation, 24% higher trunk cross-section area (TCSA) was observed, with the nitrogen and magnesium concentrations in leaves increasing, on average, by 7.8% and 64.2%, and phosphorus and potassium content decreasing by 37.2% and 46.5%, respectively. This study shows that using AMF + PGPR inoculum supports tree roots colonization by AMF. As a result, better nitrogen nutrition status is observed that promote vigorous growth of trees and more efficient uptake of magnesium from the bulk soil. On the other hand, lower phosphorus content in inoculated tree leaves might be explained by a dilution effect, and potassium decrease could occur as a result of fungus–plant competition in conditions of this element deficiency in soil.

scholarly journals The methylome of the model arbuscular mycorrhizal fungus, Rhizophagus irregularis, shares characteristics with early diverging fungi and Dikarya

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Anurag Chaturvedi ◽  
Joaquim Cruz Corella ◽  
Chanz Robbins ◽  
Anita Loha ◽  
Laure Menin ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Plant Species ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Rhizophagus Irregularis ◽  
Functional Differences ◽  
Phosphate Regulation ◽  
Very High

AbstractEarly-diverging fungi (EDF) are distinct from Dikarya and other eukaryotes, exhibiting high N6-methyldeoxyadenine (6mA) contents, rather than 5-methylcytosine (5mC). As plants transitioned to land the EDF sub-phylum, arbuscular mycorrhizal fungi (AMF; Glomeromycotina) evolved a symbiotic lifestyle with 80% of plant species worldwide. Here we show that these fungi exhibit 5mC and 6mA methylation characteristics that jointly set them apart from other fungi. The model AMF, R. irregularis, evolved very high levels of 5mC and greatly reduced levels of 6mA. However, unlike the Dikarya, 6mA in AMF occurs at symmetrical ApT motifs in genes and is associated with their transcription. 6mA is heterogeneously distributed among nuclei in these coenocytic fungi suggesting functional differences among nuclei. While far fewer genes are regulated by 6mA in the AMF genome than in EDF, most strikingly, 6mA methylation has been specifically retained in genes implicated in components of phosphate regulation; the quintessential hallmark defining this globally important symbiosis.

Effect of tiller age and time of nitrogen stress on seed production of Paspalum plicatulum

1973 ◽  
Vol 81 (2) ◽  
pp. 219-229 ◽  
Author(s):  
P. A. Chadhokar ◽  
L. R. Humphreys
Keyword(s):  
Ammonium Nitrate ◽  
Seed Size ◽  
Seed Yield ◽  
Growth And Development ◽  
Nitrogen Nutrition ◽  
Development Stage ◽  
Nitrogen Supply ◽  
Nitrogen Stress ◽  
Floral Initiation ◽  
Final Maturation

SummaryPaspalum plicatulum was grown at Brisbane in boxes of sand receiving basal nutrients and frequent irrigation; weekly levels of ammonium nitrate application were varied according to growth and development stage.The rate of tiller appearance increased to a maximum 40–50 days after sowing and almost ceased thereafter. Tiller leaf number, survival, fertility, inflorescence branching, seeds per raceme and seed size were positively related to tiller age. Young tillers were more sensitive to variations in nitrogen supply than old tillers.Adequate nitrogen nutrition during the vegetative phase from sowing to floral initiation (93 days) increased tiller and hence inflorescence density; increased inflorescence branching was compensated by fewer seeds per raceme. Good nitrogen nutrition during the phase from floral initiation to inflorescence exsertion (142 days) increased survival of late-formed tillers and hence inflorescence density; inflorescence branching, seeds per raceme and seed size were also increased. Nitrogen stress during the final maturation phase did not affect seed yield.

scholarly journals Combination of arbuscular mycorrhizal fungi and phosphate solubilizing bacteria on growth and production of Helianthus tuberosus under field condition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sabaiporn Nacoon ◽  
Sanun Jogloy ◽  
Nuntavun Riddech ◽  
Wiyada Mongkolthanaruk ◽  
Jindarat Ekprasert ◽  
...  
Keyword(s):  
Field Condition ◽  
Mycorrhizal Fungi ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Growth And Yield ◽  
Spore Density ◽  
Phosphate Solubilizing Bacteria ◽  
Phosphate Solubilizing ◽  
Inoculation Treatment ◽  
Amf Inoculation

AbstractIn this work, the effects of co-inoculation between an arbuscular mycorrhizal fungus (AMF) and a phosphate solubilizing bacteria (PSB) to promote the growth and production of sunchoke under field condition were investigated during 2016 and 2017. Four treatments were set up as follows: plants without inoculation, with AMF inoculation, with PSB inoculation and with co-inoculation of PSB and AMF. The results showed the presence of PSB and AMF colonization at the harvest stage in both years. This suggested the survival of PSB and successful AMF colonization throughout the experiments. According to correlation analysis, PSB positively affected AMF spore density and colonization rate. Also, both AMF and PSB positively correlated with growth and production of sunchoke. Co-inoculation could enhance various plant parameters. However, better results in 2016 were found in co-inoculation treatment, while AMF inoculation performed the best in 2017. All of these results suggested that our AMF and PSB could effectively promote growth and production of sunchoke under field conditions. Such effects were varied due to different environmental conditions each year. Note that this is the first study showing successful co-inoculation of AMF and PSB for promoting growth and yield of sunchoke in the real cultivation fields.

Deciphering the Chitin Code in Plant Symbiosis, Defense, and Microbial Networks

2021 ◽  
Vol 75 (1) ◽  
pp. 583-607
Author(s):  
Devanshi Khokhani ◽  
Cristobal Carrera Carriel ◽  
Shivangi Vayla ◽  
Thomas B. Irving ◽  
Christina Stonoha-Arther ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Growth And Development ◽  
Fungal Growth ◽  
Mycorrhizal Symbiosis ◽  
Signal Molecules ◽  
Symbiotic Relationship ◽  
Beneficial Microbes ◽  
Symbiotic Interactions ◽  
Microbe Interactions ◽  
Structural Polymer

Chitin is a structural polymer in many eukaryotes. Many organisms can degrade chitin to defend against chitinous pathogens or use chitin oligomers as food. Beneficial microorganisms like nitrogen-fixing symbiotic rhizobia and mycorrhizal fungi produce chitin-based signal molecules called lipo-chitooligosaccharides (LCOs) and short chitin oligomers to initiate a symbiotic relationship with their compatible hosts and exchange nutrients. A recent study revealed that a broad range of fungi produce LCOs and chitooligosaccharides (COs), suggesting that these signaling molecules are not limited to beneficial microbes. The fungal LCOs also affect fungal growth and development, indicating that the roles of LCOs beyond symbiosis and LCO production may predate mycorrhizal symbiosis. This review describes the diverse structures of chitin; their perception by eukaryotes and prokaryotes; and their roles in symbiotic interactions, defense, and microbe-microbe interactions. We also discuss potential strategies of fungi to synthesize LCOs and their roles in fungi with different lifestyles.

Susceptibility of barley cultivars to vesicular-arbuscular mycorrhizal fungi

1995 ◽  
Vol 75 (1) ◽  
pp. 269-275 ◽  
Author(s):  
S. M. Boyetchko ◽  
J. P. Tewari
Keyword(s):  
Mycorrhizal Fungi ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Growth And Yield ◽  
Vam Fungi ◽  
University Of Alberta ◽  
Barley Cultivars ◽  
Vesicular Arbuscular ◽  
Glomus Species ◽  
The University

The relative susceptibility of selected barley cultivars produced in western Canada to vesicular-arbuscular mycorrhizal (VAM) fungi under field and greenhouse conditions was evaluated in this study. Cultivars tested under field conditions at the University of Alberta and Lacombe research stations showed no significant differences in VAM colonization of barley roots; colonization was light. Greenhouse trials at the University of Alberta with eight cultivars inoculated with individual mycorrhizal species illustrated significant differences among the barley cultivars in their reactions to Glomus dimorphicum, G. intraradices, and G. mosseae. Distinct differences were observed in the ability of each Glomus species to colonize the barley cultivars. The VAM fungi increased growth and yield in some cultivars, depending on the Glomus species. This study indicates that a degree of host-specificity exists in VAM fungi and that the host-mycorrhizal fungus genotypes may influence the effectiveness of the symbiosis. Key words: Barley, cultivars, susceptibility, VA mycorrhizal fungi

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