scholarly journals Mycorrhizal Fungi Regulate Root Responses and Leaf Physiological Activities in Trifoliate Orange

2017 ◽  
Vol 45 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Chun-Yan LIU ◽  
A.K. SRIVASTAVA ◽  
Qiang-Sheng WU

Plant responses to mycorrhization are mediated through secretion of certain signal molecules deposited in mycorrhizosphere in response to environmental stimuli. Responses of four arbuscular mycorrhizal fungi (AMF), namely Claroideoglomus etunicatum, Diversispora versiformis, Funneliformis mosseae, and Rhizoglomus intraradices on root morphology, lateral root (LR) number, and leaf carbohydrates, nitric oxide (NO), and calmodulin (CaM) changes were studied using trifoliate orange. Inoculation response of D. versiformis, F. mosseae, and R. intraradices registered significantly higher plant growth performance (plant height, stem diameter, leaf number, and shoot and root biomass), root morphological traits (total length, projected area, surface area, and volume), and LR number (first-, second-, third-, and forth-order), compared to un-inoculated response. Higher concentrations of CaM, NO, glucose, and fructose and lower sucrose level in leaves were observed in AMF-seedlings than in non-AMF seedlings. Correlation studies further revealed, root morphological traits and LR numbers were significantly negatively correlated with sucrose whereas positively correlated with glucose, fructose, NO, and CaM level in leaves. These results suggested, AMF-induced root modification is routed through sucrose cleavage and partly through changes in NO and CaM.

2019 ◽  
Author(s):  
Coline Deveautour ◽  
Sally Power ◽  
Kirk Barnett ◽  
Raul Ochoa-Hueso ◽  
Suzanne Donn ◽  
...  

Climate models project overall a reduction in rainfall amounts and shifts in the timing of rainfall events in mid-latitudes and sub-tropical dry regions, which threatens the productivity and diversity of grasslands. Arbuscular mycorrhizal fungi may help plants to cope with expected changes but may also be impacted by changing rainfall, either via the direct effects of low soil moisture on survival and function or indirectly via changes in the plant community. In an Australian mesic grassland (former pasture) system, we characterised plant and arbuscular mycorrhizal (AM) fungal communities every six months for nearly four years to two altered rainfall regimes: i) ambient, ii) rainfall reduced by 50% relative to ambient over the entire year and iii) total summer rainfall exclusion. Using Illumina sequencing, we assessed the response of AM fungal communities sampled from contrasting rainfall treatments and evaluated whether variation in AM fungal communities was associated with variation in plant community richness and composition. We found that rainfall reduction influenced the fungal communities, with the nature of the response depending on the type of manipulation, but that consistent results were only observed after more than two years of rainfall manipulation. We observed significant co-associations between plant and AM fungal communities on multiple dates. Predictive co-correspondence analyses indicated more support for the hypothesis that fungal community composition influenced plant community composition than vice versa. However, we found no evidence that altered rainfall regimes were leading to distinct co-associations between plants and AM fungi. Overall, our results provide evidence that grassland plant communities are intricately tied to variation in AM fungal communities. However, in this system, plant responses to climate change may not be directly related to impacts of altered rainfall regimes on AM fungal communities. Our study shows that AM fungal communities respond to changes in rainfall but that this effect was not immediate. The AM fungal community may influence the composition of the plant community. However, our results suggest that plant responses to altered rainfall regimes at our site may not be resulting via changes in the AM fungal communities.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Peng Wang ◽  
Yin Wang

Morphological observation of arbuscular mycorrhizal fungi (AMF) species in rhizospheric soil could not accurately reflect the actual AMF colonizing status in roots, while molecular identification of indigenous AMF colonizing citrus rootstocks at present was rare in China. In our study, community of AMF colonizing trifoliate orange (Poncirus trifoliataL. Raf.) and red tangerine (Citrus reticulataBlanco) were analyzed based on small subunit of ribosomal DNA genes. Morphological observation showed that arbuscular mycorrhizal (AM) colonization, spore density, and hyphal length did not differ significantly between two rootstocks. Phylogenetic analysis showed that 173 screened AMF sequences clustered in at least 10 discrete groups (GLO1~GLO10), all belonging to the genus ofGlomusSensu Lato. Among them, GLO1 clade (clustering with uncultured Glomus) accounting for 54.43% clones was the most common in trifoliate orange roots, while GLO6 clade (clustering withGlomus intraradices) accounting for 35.00% clones was the most common in red tangerine roots. Although, Shannon-Wiener indices exhibited no notable differences between both rootstocks, relative proportions of observed clades analysis revealed that composition of AMF communities colonizing two rootstocks varied severely. The results indicated that native AMF species in citrus rhizosphere had diverse colonization potential between two different rootstocks in the present orchards.


2017 ◽  
Vol 12 (5) ◽  
pp. 159
Author(s):  
Marlina Puspita Sari ◽  
Bambang Hadisutrisno ◽  
Suryanti Suryanti

Arbuscular mycorrhizal fungi (AMF) is known to improve the growth of shallot (Allium cepa var. aggregatum) and strengthen the resistance of plants toward disease infection.  This research aimed to find out the roles of AMF in suppressing the development of purple blotch disease caused by  Alternaria sp. on shallot in Caturtunggal, Sleman, Yogyakarta.  Inoculation of AMF either on fertilization of N, P, K or without fertilization treatment resulted on higher plant height and number of leaves compared to those without AMF inoculation. The plant inoculated with AMF had lower purple blotch disease intensity and disease progression than control and fungicide treatment. The result showed that AMF, in addition to act as the bio-fertilizer, is a potential to be a biocontrol agent.


2018 ◽  
Vol 46 (1) ◽  
pp. 270-276 ◽  
Author(s):  
Fei ZHANG ◽  
Jia-Dong HE ◽  
Qiu-Dan NI ◽  
Qiang-Sheng WU ◽  
Ying-Ning ZOU

Sucrose and proline metabolisms are often associated with drought tolerance of plants. This study was conducted to investigate the effects of two arbuscular mycorrhizal fungi (AMF) species (Funneliformis mosseae and Paraglomus occultum) on root biomass, lateral root number, root sucrose and proline metabolisms in trifoliate orange (Poncirus trifoliata) seedlings under well-watered (WW) or drought stress (DS). All the AMF treatments significantly increased root dry weight, taproot length, and the number of lateral roots in 1st, 2nd, and 3rd class under WW and DS. Mycorrhizal seedlings conferred considerably higher fructose and glucose concentrations but lower sucrose accumulation, regardless of soil water status. Under DS, F. mosseae treatment significantly increased root sucrose synthase (SS, degradative direction) and sucrose phosphate synthase (SPS) activity but deceased root acid invertase (AI) and neutral invertase (NI) activity, and P. occultum inoculation markedly increased root AI, NI, SS, and SPS activities. AMF treatments led to a lower proline accumulation in roots, in company with lower activities of Δ1-pyrroline-5-carboxylate synthetase (P5CS), δ-ornithine aminotransferase (OAT), Δ1-pyrroline-5-carboxylate reductase (P5CR), and proline dehydrogenase (ProDH) in roots. It appears that the AM symbiosis induced greater root development and sucrose and proline metabolisms to adapt DS.


2010 ◽  
Vol 11 (1) ◽  
pp. 53 ◽  
Author(s):  
Margarita Ramírez Gómez ◽  
Alia Rodríguez Villate

<p>La asociación entre Hongo formadores de micorrizas arbusculares (HFMA) y las plantas ha permitido la adaptación de éstas a ecosistemas terrestres, presentándose en más del 80% de las plantas. El hospedero suministra carbohidratos al hongo y éste transporta los nutrientes que la planta requiere. El establecimiento de la simbiosis requiere procesos armónicos a nivel espacio-temporal, que dependen de señales específicas, para reconocimiento, colonización e intercambio de nutrientes. Las plantas presentan respuestas de defensa frente a la posible invasión de microorganismos, sin embargo, en la simbiosis éstas son débiles, localizadas y no impiden la colonización del hongo. Estas señales se observan en todas las etapas de la simbiosis, siendo la primera señal enviada por la planta en exudados de la raíz, especialmente en condiciones de bajo fósforo. Posteriormente los HFMA activan la expresión de genes que favorecen cambios a nivel celular para la formación del apresorio, del aparato de pre-penetración y en células de la corteza, del arbúsculo y la membrana periarbuscular, para el intercambio de nutrientes. Un aspecto de interés está relacionado con los mecanismos de atenuación de las respuestas de defensa de la planta. Se han planteado diversas hipótesis para entender este fenómeno y aunque el control de la simbiosis está regulado principalmente por la planta, aún se desconoce si los HFMA generan señales que facilitan el debilitamiento de las respuestas de defensa del hospedero. Este documento está orientado a hacer una revisión de las señales de reconocimiento HFMA - plantas para cada fase de la simbiosis, así como de algunos mecanismos de regulación de las respuestas de defensa de la planta para el establecimiento de la simbiosis.</p><p> </p><p><strong>Recognition Signalling Between Arbuscular Mycorrhizal Fungi (AMF) and Plants</strong></p><p> </p>The arbuscular mycorrhizal association has been instrumental for plant adaptation to terrestrial ecosystems over the last 400 million years. It is known that more than 80% of plant families form this symbiosis .Thus, nutrient exchange and protection from pathogens are thought to be key elements in the symbiosis. For the establishment of the association, harmonic processes for recognition, colonization and nutrients exchange are required both at temporal and space level. Plants react against microorganisms attack by producing defense responses, however, in the case of AM association, plant responses are weak, localized and do not stop colonization by the fungus. Signals are observed along the whole symbiosis process, being the first one produced by the plant through root exudates as a response for P stress. Then, AMF activate genes involved in plant cellular changes required for arbuscle formation, pre-penetration apparatus and at cortex level, the formation of periarbuscular membrane for the bi-directional nutrient exchange. Interestingly, several hypotheses have been formulated to explain the plant defense attenuation. For example, the activation of defense suppressors, the existence of plants with no defence responses to AMF and the existence of plants that suppress their defense response, among others. It is unknown whether the fungi induce low response levels from the host defense system. This document focuses on the signaling recognition between AMF and plants in each symbiosis phase and on the regulation mechanisms of the plant defense responses for the symbiosis establishment.


2021 ◽  
Vol 19 (2) ◽  
pp. 131-141
Author(s):  
Alexey M. Afonin ◽  
Emma S. Gribchenko ◽  
Evgeny A. Zorin ◽  
Anton S. Sulima ◽  
Daria A. Romanyuk ◽  
...  

BACKGROUND: Garden pea (Pisum sativum L.) possesses the ability to form beneficial symbioses with various soil microorganisms. However, different pea cultivars, genotypes, and lines gain more or less benefit from these interactions, so the trait named efficiency of interaction with soil microorganisms (EIBSM) was suggested to describe this phenomenon. The molecular mechanisms underlying the manifestation of the EIBSM trait are not properly studied, and only few works focusing on plant responses to combined microbial preparations have been published to date. METHODS: Eight pea lines previously described as contrasting in manifestation of the EIBSM trait were grown in pots with soil under combined inoculation with nodule bacteria and arbuscular mycorrhizal fungi, and the transcriptome profiles of the whole root systems of the plants were investigated using 3'MACE RNA sequencing. RESULTS: The relatedness of the lines inferred from the analysis of transcripts SNVs (Single Nucleotide Variants) corresponded to the manifestation of the EIBSM trait: three high-EIBSM lines and three low-EIBSM lines formed two distinct clusters. Thus, the gene expression profiles were compared between these two clusters, which enabled identification of transcriptome signatures characteristic for each group. The lines previously described as high-EIBSM have lower symbiotic activity, and the expression levels of pathogen response genes were elevated compared to the lines with low EIBSM. CONCLUSION: This result suggests that the mechanism of high interaction efficiency may be connected to stricter host control of symbionts, allowing such plants to expend less on the symbioses.


2021 ◽  
Vol 12 ◽  
Author(s):  
Sheng-Min Liang ◽  
Fei Zhang ◽  
Ying-Ning Zou ◽  
Kamil Kuča ◽  
Qiang-Sheng Wu

Soil water deficit seriously affects crop production, and soil arbuscular mycorrhizal fungi (AMF) enhance drought tolerance in crops by unclear mechanisms. Our study aimed to analyze changes in non-targeted metabolomics in roots of trifoliate orange (Poncirus trifoliata) seedlings under well-watered and soil drought after inoculation with Rhizophagus intraradices, with a focus on terpenoid profile. Root mycorrhizal fungal colonization varied from 70% under soil drought to 85% under soil well-watered, and shoot and root biomass was increased by AMF inoculation, independent of soil water regimes. A total of 643 secondary metabolites in roots were examined, and 210 and 105 differential metabolites were regulated by mycorrhizal fungi under normal water and drought stress, along with 88 and 17 metabolites being up-and down-regulated under drought conditions, respectively. KEGG annotation analysis of differential metabolites showed 38 and 36 metabolic pathways by mycorrhizal inoculation under normal water and drought stress conditions, respectively. Among them, 33 metabolic pathways for mycorrhization under drought stress included purine metabolism, pyrimidine metabolism, alanine, aspartate and glutamate metabolism, etc. We also identified 10 terpenoid substances, namely albiflorin, artemisinin (−)-camphor, capsanthin, β-caryophyllene, limonin, phytol, roseoside, sweroside, and α-terpineol. AMF colonization triggered the decline of almost all differential terpenoids, except for β-caryophyllene, which was up-regulated by mycorrhizas under drought, suggesting potential increase in volatile organic compounds to initiate plant defense responses. This study provided an overview of AMF-induced metabolites and metabolic pathways in plants under drought, focusing on the terpenoid profile.


2006 ◽  
Vol 86 (4) ◽  
pp. 941-950 ◽  
Author(s):  
Chantal Hamel ◽  
Désiré-Georges Strullu

Arbuscular mycorrhizal fungi (AMF) are multipurpose organisms with complex ecological ramifications in the soil system that have been difficult to study and understand. The phytocentric concept of AMF that has prevailed since the naming of these organisms is being replaced by a holistic vision recognizing that AMF are a key element of soil functioning and health rather than a plant root component. Recent advances in knowledge brought about by new techniques for soil microbiology research open the way to AMF management in crop production. Arbuscular mycorrhizal fungi may influence crop development, even in phosphorus-rich soils. However, growing crops in soil with lower fertility would optimize the expression of the multiple beneficial effects of AMF in agro-ecosystem and reduce nutrient seepage to the environment. The consideration of the soil mycorrhizal potential within the framework of soil testing and fertilization recommendations, the development of improved inoculants and signal molecules to manipulate AMF and the development of cultivars with improved symbiotic qualities would insure the production of good crop yields while improving agroecosystems’ sustainability. Key words: Arbuscular mycorrhizal fungi management, field crop production, agriculture, soil quality, arbuscular mycorrhizal effect


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