Simultaneous in situ detection of alkaline phosphatase activity and polyphosphate in arbuscules within arbuscular mycorrhizal roots

2007 ◽  
Vol 34 (9) ◽  
pp. 803 ◽  
Author(s):  
Rintaro Funamoto ◽  
Katsuharu Saito ◽  
Hiroshi Oyaizu ◽  
Masanori Saito ◽  
Toshihiro Aono
Keyword(s):  
Alkaline Phosphatase ◽  
Inorganic Phosphate ◽  
Host Plants ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Alp Activity ◽  
Mycorrhizal Roots ◽  
In Situ Detection ◽  
Labelling Method

Inorganic phosphate (Pi) metabolism in arbuscules of arbuscular mycorrhizal (AM) fungi is not well understood, although recent research has revealed that host plants absorb Pi around arbuscules with mycorrhiza-specific transporters. Therefore, we analysed the localisation of polyphosphate (polyP) and alkaline phosphatase (ALP) activity in arbuscules, which could be indicators of Pi metabolism. We developed a dual-labelling method for polyP and ALP activity, i.e. first labelling with fluorescent probes 4′,6-diamidino-2-phenyl-indole dihydrochloride (DAPI) and then labelling with enzyme-labelled fluorescence (ELF97). The dual-labelling method made it possible to observe polyP and ALP activity signals simultaneously in mycorrhizal roots. The dual-labelling method revealed that ALP activity was mainly observed in mature arbuscules where polyP was rarely observed. The expression of the AM fungal ALP gene was suppressed in the knockdown plants of an AM-inducible Pi-transporter, and there was much polyP in arbuscules that showed low ALP activity. These topological observations suggest that there may be some relationships between polyP metabolism and ALP activity in arbuscules, and that these are, in part, controlled by Pi uptake by plants via the AM-inducible Pi-transporter.

scholarly journals Elucidating the Mechanisms Underlying Enhanced Drought Tolerance in Plants Mediated by Arbuscular Mycorrhizal Fungi

2021 ◽  
Vol 12 ◽  
Author(s):  
Shen Cheng ◽  
Ying-Ning Zou ◽  
Kamil Kuča ◽  
Abeer Hashem ◽  
Elsayed Fathi Abd_Allah ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Mycorrhizal Fungi ◽  
Host Plants ◽  
Molecular Mechanisms ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Host Cells ◽  
Future Research ◽  
Symbiotic Association

Plants are often subjected to various environmental stresses during their life cycle, among which drought stress is perhaps the most significant abiotic stress limiting plant growth and development. Arbuscular mycorrhizal (AM) fungi, a group of beneficial soil fungi, can enhance the adaptability and tolerance of their host plants to drought stress after infecting plant roots and establishing a symbiotic association with their host plant. Therefore, AM fungi represent an eco-friendly strategy in sustainable agricultural systems. There is still a need, however, to better understand the complex mechanisms underlying AM fungi-mediated enhancement of plant drought tolerance to ensure their effective use. AM fungi establish well-developed, extraradical hyphae on root surfaces, and function in water absorption and the uptake and transfer of nutrients into host cells. Thus, they participate in the physiology of host plants through the function of specific genes encoded in their genome. AM fungi also modulate morphological adaptations and various physiological processes in host plants, that help to mitigate drought-induced injury and enhance drought tolerance. Several AM-specific host genes have been identified and reported to be responsible for conferring enhanced drought tolerance. This review provides an overview of the effect of drought stress on the diversity and activity of AM fungi, the symbiotic relationship that exists between AM fungi and host plants under drought stress conditions, elucidates the morphological, physiological, and molecular mechanisms underlying AM fungi-mediated enhanced drought tolerance in plants, and provides an outlook for future research.

Novel Insights into Host Receptors and Receptor-mediated Signaling that Regulate Arbuscular Mycorrhizal Symbiosis

2020 ◽  
Author(s):  
Fahad Nasir ◽  
Ali Bahadur ◽  
Xiaolong Lin ◽  
Yingzhi Gao ◽  
Chunjie Tian
Keyword(s):  
Host Plant ◽  
Host Plants ◽  
Agronomic Traits ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Land Plant ◽  
Physical Contact ◽  
Mycorrhizal Symbiosis ◽  
Downstream Signaling ◽  
Am Symbiosis

Abstract More than 80% of land plant species benefit from symbiotic partnerships with arbuscular mycorrhizal (AM) fungi that assist in nutrient acquisition and enhance the ability of host plants to adapt to environmental constraints. Host-generated plasma membrane-residing receptor-like kinases and the α/β-hydrolases, e.g. DWARF14-LIKE (D14L), a putative karrikin receptor, are used to detect the presence of AM fungi prior to physical contact between the host and fungus. Detection induces the activation of symbiosis-related transcriptional programming, enabling the successful establishment of AM symbiosis. In order to prevent hyper-colonization and to maintain a mutually beneficial association, the host plants precisely monitor and control AM symbiosis during the post-symbiotic stage via different molecular strategies. While previous studies have elucidated how host plant receptors and receptor-mediated signaling regulate AM symbiosis, the molecular details underlying these processes remain poorly understood. The recent identification of a rice (Oryza sativa) CHITIN-ELICITOR RECEPTOR-KINASE 1 (OsCERK1) interaction partner MYC FACTOR RECEPTOR 1 (OsMYR1), as well as new insights into D14L-receptor- and SUPER NUMERIC NODULES 1 (SUNN1) receptor-mediated signaling have improved our understanding of how host plant receptors and their corresponding signaling regulate AM symbiosis. The present review summarizes these and other current findings that have increased our limited understanding of receptor-mediated signaling mechanisms involved in the regulation of AM symbiosis. The identified receptors and/or their downstream signaling components could potentially be used to engineer economically-important crops with improved agronomic traits by conferring the ability to control the colonization of AM fungi in a precise manner.

scholarly journals Investigation of Indigenous Arbuscular Mycorrhizal Performance Using a Lotus japonicus Mycorrhizal Mutant

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 658
Author(s):  
Taisuke Teranishi ◽  
Yoshihro Kobae
Keyword(s):  
Plant Growth ◽  
Arbuscular Mycorrhiza ◽  
Host Plants ◽  
Lotus Japonicus ◽  
Soil Management ◽  
Arbuscular Mycorrhizal ◽  
Mineral Nutrients ◽  
Wild Type ◽  
Arbuscular Mycorrhiza Fungi ◽  
Mycorrhizal Roots

Most plants are usually colonized with arbuscular mycorrhiza fungi (AMF) in the fields. AMF absorb mineral nutrients, especially phosphate, from the soil and transfer them to the host plants. Inoculation with exotic AMF is thought to be effective when indigenous AMF performance is low; however, there is no method for evaluating the performance of indigenous AMF. In this study, we developed a method to investigate the performance of indigenous AMF in promoting plant growth. As Lotus japonicus mutant (str) that are unable to form functional mycorrhizal roots were considered to be symbiosis negative for indigenous mycorrhizal performance, we examined the growth ratios of wild-type and str mycorrhizal mutant using 24 soils. Each soil had its own unique indigenous mycorrhizal performance, which was not directly related to the colonization level of indigenous AMF or soil phosphate level. The low indigenous mycorrhizal performance could not be compensated by the inoculation of exotic AMF. Importantly, indigenous mycorrhizal performance was never negative; however, the inoculation of exotic AMF into the same soil led to both positive and negative performances. These results suggest that indigenous mycorrhizal performance is affected by soil management history and is basically harmless to the plant.

scholarly journals Expression Pattern Suggests a Role of MiR399 in the Regulation of the Cellular Response to Local Pi Increase During Arbuscular Mycorrhizal Symbiosis

2010 ◽  
Vol 23 (7) ◽  
pp. 915-926 ◽  
Author(s):  
Anja Branscheid ◽  
Daniela Sieh ◽  
Bikram Datt Pant ◽  
Patrick May ◽  
Emanuel A. Devers ◽  
...  
Keyword(s):  
Cellular Response ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Mycorrhizal Symbiosis ◽  
Pi Homeostasis ◽  
Pi Starvation ◽  
Mycorrhizal Roots ◽  
Am Symbiosis ◽  
Pi Stress

Many plants improve their phosphate (Pi) availability by forming mutualistic associations with arbuscular mycorrhizal (AM) fungi. Pi-repleted plants are much less colonized by AM fungi than Pi-depleted plants. This indicates a link between plant Pi signaling and AM development. MicroRNAs (miR) of the 399 family are systemic Pi-starvation signals important for maintenance of Pi homeostasis in Arabidopsis thaliana and might also qualify as signals regulating AM development in response to Pi availability. MiR399 could either represent the systemic low-Pi signal promoting or required for AM formation or they could act as counter players of systemic Pi-availability signals that suppress AM symbiosis. To test either of these assumptions, we analyzed the miR399 family in the AM-capable plant model Medicago truncatula and could experimentally confirm 10 novel MIR399 genes in this species. Pi-depleted plants showed increased expression of mature miR399 and multiple pri-miR399, and unexpectedly, levels of five of the 15 pri-miR399 species were higher in leaves of mycorrhizal plants than in leaves of nonmycorrhizal plants. Compared with nonmycorrhizal Pi-depleted roots, mycorrhizal roots of Pi-depleted M. truncatula and tobacco plants had increased Pi contents due to symbiotic Pi uptake but displayed higher mature miR399 levels. Expression levels of MtPho2 remained low and PHO2-dependent Pi-stress marker transcript levels remained high in these mycorrhizal roots. Hence, an AM symbiosis-related signal appears to increase miR399 expression and decrease PHO2 activity. MiR399 overexpression in tobacco suggested that miR399 alone is not sufficient to improve mycorrhizal colonization supporting the assumption that, in mycorrhizal roots, increased miR399 are necessary to keep the MtPho2 expression and activity low, which would otherwise increase in response to symbiotic Pi uptake.

scholarly journals Conjugate formation in urea: coupling of insoluble peptides to alkaline phosphatase for ELISA and in situ detection of antibody-forming cells.

1991 ◽  
Vol 39 (7) ◽  
pp. 987-992 ◽  
Author(s):  
K Gerritse ◽  
M Fasbender ◽  
W Boersma ◽  
E Claassen
Keyword(s):  
Alkaline Phosphatase ◽  
Synthetic Peptide ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sufficient Degree ◽  
Antipeptide Antibody ◽  
In Situ Detection ◽  
Antibody Secreting Cells

We report here a new method to produce synthetic peptide/alkaline phosphatase (AP) conjugates in the presence of urea. The method allows the use of peptides that are not soluble to a sufficient degree in aqueous buffers. The presence of 8 M urea during the construction of the synthetic peptide/AP conjugates does not influence enzyme activity nor the affinity of the anti-peptide antibodies for the conjugated peptide. We demonstrate that these synthetic peptide/AP conjugates can be used for detection of specific antipeptide antibody-forming cells (AFC) in vivo. This method for constructing enzyme conjugates with insoluble proteins or peptides suggest not only new possibilities for detection of specific AFC in vivo but also for applications in receptor-ligand studies, ELISA (enzyme-linked immunosorbent assay), and spot ELISA for detection of antibody-secreting cells in vitro.

scholarly journals A novel fluorogenic substrate for detecting alkaline phosphatase activity in situ.

1993 ◽  
Vol 41 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Z Huang ◽  
W You ◽  
R P Haugland ◽  
V B Paragas ◽  
N A Olson ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Cell Line ◽  
Egf Receptor ◽  
Egf Receptors ◽  
Fluorogenic Substrate ◽  
Epidermal Growth ◽  
In Situ Detection ◽  
Apase Activity ◽  
Human Epidermoid Carcinoma

We describe here the in situ detection of alkaline phosphatase (APase) activity with a new fluorogenic substrate, 2-(5'-chloro-2'-phosphoryloxyphenyl)-6-chloro-4-(3H)-quinazolinone (CPPCQ). CPPCQ is very soluble and colorless. APase converts it into a rapidly precipitating product, whose strong fluorescence marks the sites of APase activity. The detected APase was either a probing enzyme anchored to epidermal growth factor (EGF) receptors of fixed human epidermoid carcinoma cell line (A431) by biotinylated EGF and streptavidin-APase conjugates or an endogenous marker existing in a fixed canine kidney cell line (MDCK). With CPPCQ staining, the EGF receptors and the endogenous APase were both visualized by fluorescence microscopy as contrasting, photostable, and well-resolved fluorescent stains. The EGF receptor staining was specific since it could be blocked by excessive unlabeled EGF. In contrast, fluorescein-labeled EGF failed to specifically stain the EGF receptors under the same fluorescent microscope. The endogenous APase staining with CPPCQ was sensitive to heating, levamisole and L-homoarginine, showing an APase tissue specificity of the liver/bone/kidney type. Therefore, CPPCQ appears to be a novel substrate dye for sensitive fluorescence APase histochemistry.

scholarly journals Plants export 2-monopalmitin and supply both fatty acyl and glyceryl moieties to arbuscular mycorrhizal fungi

2021 ◽  
Author(s):  
Leonie H Luginbuehl ◽  
Harrie van Erp ◽  
Henry Cheeld ◽  
Kirankumar S Mysore ◽  
Jiangqi Wen ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Host Plants ◽  
Acyl Carrier Protein ◽  
Ectopic Expression ◽  
Arbuscular Mycorrhizal ◽  
Fatty Acyl ◽  
Storage Lipids ◽  
Atp Binding Cassette Transporter ◽  
Mycorrhizal Roots

ABSTRACTArbuscular mycorrhizal fungi (AMF) rely on their host plants to provide them with fatty acids (FA), but the precise form(s) in which they are supplied is still unclear. Here we show that ectopic expression of the transcription factor REQUIRED FOR ARBUSCULAR MYCORRHIZATION 1 (RAM1) can drive secretion of 2-monoacylglycerols (2MGs) from Medicago truncatula roots and that their main FA moiety is palmitic acid, although myristic acid and stearic acid were also detected. RAM1-dependent 2MG secretion requires the acyl-acyl carrier protein thioesterase FATM, the glycerol-3-phosphate (G3P) acyltransferase RAM2 and the ATP binding cassette transporter STR. Furthermore, 14C glycerol labelling experiments using mycorrhizal M. truncatula roots that are deficient in glycerol kinase, FAD-dependent G3P dehydrogenase and the G3P acyltransferase RAM2 suggest that most of the glyceryl moieties in Rhizophagus irregularis storage lipids are provided by their host plant through the 2MG pathway. Taken together, our data support the hypothesis that the plant exports 2MGs across the peri-arbuscular membrane in mycorrhizal roots and that the AMF receive and utilise both the FA and glyceryl moieties to make their storage lipids.

scholarly journals Investigating the diversity of arbuscular mycorrhizal fungi from Gymnema sylvestre and Curcuma longa in Vietnam

2020 ◽  
Vol 16 (4) ◽  
pp. 697-703
Author(s):  
Hoang Kim Chi ◽  
Tran Thi Nhu Hang ◽  
Tran Thi Hong Ha ◽  
Le Huu Cuong ◽  
Tran Ho Quang ◽  
...  
Keyword(s):  
Medicinal Plants ◽  
Host Plants ◽  
Rhizosphere Soil ◽  
Curcuma Longa ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Fungal Species ◽  
Soil Samples ◽  
Rrna Gene ◽  
Gymnema Sylvestre

Arbuscular mycorrhizal (AM) fungi are soil eukaryotes that belong to phylum Glomeromycota and have symbiosis with the vast majority of higher plants’ roots. AM fungi are believed to be coevolved with terrestrial plants, the abundance and diversity of AM fungal communities as a result are host plant dependent. A survey of AM fungi from the rhizospheres of medicinal plants in Northern Vietnam including gurma Gymnema sylvestre and turmeric Curcuma longa was carried out. From the extracted total DNAs of the medicinal plants’ rhizosphere soil samples, 35 mycorrhizal fungal species were identified by analyzing small subunit rRNA gene sequences. Result revealed that genus Glomus is the most abundant in the AM communities of G. sylvestre and C. longa, followed by Gigaspora and Acaulospora. Besides, AM species belonging to genera Scutellospora, Diversispora and Rhizophagus were observed in almost all rhizosphere soil samples. The spore counting by wet sieving and decanting method uncovered a variation in AM spore density of gurma and turmeric rhizosphere. In general, AM species were found more abundantly and more diverse in collected rhizome soil samples of C. longa (27 species belonging to 10 genera) than of G. sylvestre (17 species found belonging to 7 genera). The observed difference in AM communities of G. sylvestre and C. longa supports evidence for the dependence of AM fungal species on host plants, and indicates that AM fungi may have relation to the host plants’ secondary metabolite production.

scholarly journals Tillage or no-tillage: Impact on mycorrhizae

2005 ◽  
Vol 85 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Zahangir Kabir
Keyword(s):  
Cover Crops ◽  
Host Plants ◽  
Conservation Tillage ◽  
Aggregate Stability ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Soil Aggregate ◽  
Soil Aggregate Stability ◽  
Tillage Practices ◽  
Fungal Propagules

Arbuscular mycorrhizal (AM) fungi are ubiquitous in agricultural soils. These fungi play important roles in plant nutrition and soil conservation. The persistence of AM fungi in ecosystems depends on the formation and survival of propagules (e.g., spore, hyphae and colonized roots). While spores are considered to be resistant structure that may be view as “long-term” propagules when viable host plants are not present, hyphae are considered to be the main source of inocula when host plants are present and the soil is not disturbed. Tillage is an integral part of modern agriculture that can modify the physical, chemical and biological properties of a soil. Consequently, tillage practices may also affect AM fungi. The various tillage practices used in the management of soil for maximum crop production may negatively impact the survival of AM fungal propagules. In tilled soil, certain AM species may survive while others may disappear. Because AM fungi are more abundant in the topsoil, deep plowing may dilute their propagules in a greater volume of soil, thereby reducing the level of infection of a plant root. Tillage is particularly detrimental to AM hyphae if the soil is tilled in the fall and the hyphae are detached from the host plant. Under no-till (NT), AM fungi survive better, particularly when they are close to the host crop on which they developed. There is speculation that in NT systems, plants may follow old root channels and potentially encounter more AM fungal propagules than plants growing in soil that has been tilled. Management of AM fungi in NT soil is essential to maximizing benefits to crops. This review reports how tillage practices affect AM fungi species richness, survivability and infectivity, and how conservation tillage can increase AM fungi survival, consequently improving plant phosphorus uptake and soil aggregate stability. Key words: Arbuscular mycorrhizal fungi, conservation tillage, conventional tillage, P uptake, soil aggregate stability, cover crops, crop yield

scholarly journals Suppression of fungal and nematode plant pathogens through arbuscular mycorrhizal fungi

2011 ◽  
Vol 8 (2) ◽  
pp. 214-217 ◽  
Author(s):  
Stavros D. Veresoglou ◽  
Matthias C. Rillig
Keyword(s):  
Mycorrhizal Fungi ◽  
Fungal Pathogens ◽  
Host Plants ◽  
Plant Pathogens ◽  
Meta Analysis ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Terrestrial Plants ◽  
Pathogen Suppression ◽  
Mycorrhizal Ecology

Arbuscular mycorrhizal (AM) fungi represent ubiquitous mutualists of terrestrial plants. Through the symbiosis, plant hosts, among other benefits, receive protection from pathogens. A meta-analysis was conducted on 106 articles to determine whether, following pathogen infection of AM-colonized plants, the identity of the organisms involved (pathogens, AM fungi and host plants) had implications for the extent of the AM-induced pathogen suppression. Data on fungal and nematode pathogens were analysed separately. Although we found no differences in AM effectiveness with respect to the identity of the plant pathogen, the identity of the AM isolate had a dramatic effect on the level of pathogen protection. AM efficiency differences with respect to nematode pathogens were mainly limited to the number of AM isolates present; by contrast, modification of the ability to suppress fungal pathogens could occur even through changing the identity of the Glomeraceae isolate applied. N-fixing plants received more protection from fungal pathogens than non-N-fixing dicotyledons; this was attributed to the more intense AM colonization in N-fixing plants. Results have implications for understanding mycorrhizal ecology and agronomic applications.

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