Search

The size and quality of the melon fruit yield depend on the cultivar, climatic and agronomic factors. A three-year field experiment investigated the effect of arbuscular mycorrhizal fungi (AMF) application and irrigation (IR) on the fruit yield of melon (Cucumis melo L. var. saccharinus Naud.) cultivars. The study was conducted on a certified organic farm located in south-eastern Poland (51.36° N, 22.83° E). The factors of the experiment were as follows: cultivar (Melba, Emir F1, Seledyn F1, Oliwin) and cultivation method (AMF and IR; AMF and non-IR; non-AMF and IR; non-AMF and non-IR as control). The dry matter (%), soluble solid (%), total sugar and reducing sugar (% fresh weight, FM), L-ascorbic acid (mg · 100 g−1 FM), and carotenoid (mg · 100 g−1 FM) contents of the fruit were determined. The highest total and marketable fruit yields were obtained using AMF and IR. Fruit from the AMF series (IR and non-IR) had the most carotenoids (respectively: 801.5 and 788.8 µg · 100 g−1 FM). The fruits of the AMF and IR plants contained the most total sugars (5.98%) and reducing sugars (2.91%) compared to the others. The control plants had the lowest number of marketable fruit, total and marketable fruit yield, and accumulated the least L-ascorbic acid, total sugars and reducing sugars. We suggest that AMF and IR can be recommended as a practical agronomic solutions for the field cultivation of melon under temperate climate conditions. [ABSTRACT FROM AUTHOR]

Phaseolus vulgaris L. (Fabaceae) forms symbioses with arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing rhizobia (NFB). The tripartite relationship uses molecular singals to establish intracellular symbioses in roots. The goal of this study was to determine if Rhizobium tropici CIAT 899 and exogenous riboflavin (vitamin B2) have an effect on AMF species selection and root colonization of P. vulgaris. Using SSU rRNA fragment amplification of DNA extracted from P. vulgaris roots, we found that the presence of R. tropici altered the relative distribution of AMF species. Dominikia bernensis (Ohel) was the most abundant AMF species in P. vulgaris roots but when R. tropici was co-inoculated, Glomus species dominated. Rhizobacteria such as R. tropici, secrete riboflavin and could affect AMF symbiosis. Addition of 50 μM riboflavin to P. vulgaris, increased plant growth (28%), dry nodule weight (18%), AMF colonization (248%) and mycorrhizal vesicle frequency (56%) in bean roots. 3.12 and 12.5 µM riboflavin favored the presence of Glomus macrocarpum in P. vulgaris roots. This work provides the basis to further study of rhizobial and mycorrhizal co-inoculation of Phaseolus vulgaris bean. [ABSTRACT FROM AUTHOR]

Invasive weeds of the Asteraceae family are widespread in the world. Arbuscular mycorrhiza (AM) is one of the main factors contributing to the successful distribution of these species that is most clearly manifested in the subfamily Asteroideae. The benefits of plant-AMF symbiosis are most significant under unfavorable biotic and abiotic conditions. The specificity of the relationship between arbuscular mycorrhizal fungi (AMF) communities and plants and is determined at the presymbiotic stage. The AMF colonization level is higher in invasive species than in native ones, but AMF communities associated with Asteraceae invasive species are less diverse. AMF communities of Asteraceae invaders often include fewer common species (e.g., species belonging to Diversisporales). Invaders also reduce native AMF species richness in new areas. Arbuscular mycorrhizal fungi can form mycorrhizal networks that allow the redistribution of nutrients in plant communities. The most significant influence of AMF associated with invasive Asteraceae plants is seen in the formation of soil and rhizosphere microbiota, including the suppression of beneficial soil bacteria and fungi. This review could be useful in the development of practical recommendations for the use of AMF-based fertilizers. [ABSTRACT FROM AUTHOR]

Various technologies, such as light-emitting diodes (LEDs) and beneficial plant micro-organisms, have been applied to enhance plant growth and development. We aimed to develop appropriate technology by incorporating the benefits of LED light, plant growth promoting rhizobacteria (PGPR), and arbuscular mycorrhiza fungi (AMF) into sweet girl cherry tomato (Solanum lycopersicum L.) seedling production. Our results demonstrated that incorporating red (R) and blue (B) LED lights, PGPR, and AMF positively affected tomato seedling growth. The optimal lighting conditions for tomato seedling growth were LEDs at 200 µmol/m2/s with a ratio of R60:B40 and 20 h/d exposure. The optimum LED-illuminated tomato seedlings significantly upregulated photosynthesis-related genes, including psbA, psbB, fdx, atpB, and rbcL. Plants inoculated with PGPR Bradyrhizobium sp. SUTN9-2, Bacillus velezensis SD10 and B. megaterium A20 had a high health index after inoculation. Furthermore, the optimized LED-illuminated tomato seedlings inoculated with SD10 had the highest health index. In addition, the optimum LED-illuminated tomato seedlings inoculated with SD10 and AMF had the highest biomass. Our experiment demonstrated that tomato seedlings produced under optimized LED lights inoculated with SD10 and AMF increased yield by about 16% under field conditions. Therefore, these results provided the optimum conditions for a high-quality tomato seedling production system. [ABSTRACT FROM AUTHOR]

Nitrogen (N) deposition is known to significantly affect plant growth. Mycorrhizas play an important role in plant productivity, and plants of different mycorrhizal types respond differently to global change, which will inevitably affect plant response to N deposition. However, little is known about the differences of different mycorrhizas in biomass allocation of host plants in response to N addition. Here, a meta-analysis of data from N addition experiments was carried out to analyze the response of biomass in arbuscular mycorrhiza (AM) and ectomycorrhiza (ECM) plants to N addition. The results showed that biomass of leaf, stem, fine root (FR), and litter between AM and ECM plants responded differently to N addition (p < 0.05). Among them, biomass of leaf and stem in ECM plants (leaf: 46.89%; stem: 45.59%) was more sensitive (positively) to N addition than AM plants (leaf: 27.84%; stem: 10.30%) (p < 0.05). N addition suppressed biomass of FR in AM plants (−11.22%) but promoted that in ECM plants (13.77%). The effects on biomass also varied with different functional groups between AM and ECM plants. However, the N responses were influenced by other resources. When other treatments were added, biomass was less varied in AM plants compared to ECM plants. In addition, the N response of WB (whole biomass) and root biomass were positively correlated with annual temperature in ECM plants, but that in AM plants did not. The effects on shoot biomass in AM and ECM plants to N addition both decreased with annual temperature. The N response of root biomass increased with annual precipitation. It can be seen that different mycorrhizal types regulate the response of different plant organ biomass to N addition, which is significant for predicting ecosystem responses and feedback to environmental change. [ABSTRACT FROM AUTHOR]

We studied changes in plant growth, nutrient absorption, quality of fresh leaves, and the antioxidant enzyme systems of leaves treated with AMF (Glomus etunicatum) in tea (tea cultivar "Xinyang 10") seedlings exposed to 0 and 100 mmol/L sodium chloride (NaCl). The AMF colonization in the tea roots decreased observably by 50.1% after a 5-week soil NaCl (100 mmol/L) treatment. The growth, leaf nutrient levels, and leaf quality parameter contents significantly declined by 18–39% in the 100 mmol/L NaCl treatments. In contrast, these variables exhibited observably higher responses in the mycorrhizal seedlings than in the nonmycorrhizal seedlings. Furthermore, AMF improved the leaves' total amino acid concentrations dramatically, accompanied by the upregulation of the genes of the amino acid synthetic enzymes, such as glutamate dehydrogenase (CsGDH), glutamate synthase (CsGOGAT), and glutamine synthetase (CsGS), while 100 mmol/L NaCl seedlings represented a negative performance. In addition, the 100 mmol/L NaCl treatments dramatically downregulated the expression level of the tea caffeine synthase 1 gene (CsTCS1), the ascorbate peroxidase gene (CsAPX), and the 3-hydroxy-3-methylglutaryl coenzyme gene (CsHMGR) in the leaves, while the AMF seedlings represented positive performances. These results suggest that AMF may play an active role in fresh leaf quality via the partial upregulation of the relevant genes' expression. In contrast, salt stress represented the opposite result in tea. The seedlings inoculated with AMF showed significantly increased antioxidant enzyme activities, by 13.3–19.6%, including peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD), over the non-AMF inoculated tea seedlings. Still, they did not affect glutathione reductase (GR), irrespective of the NaCl condition. Further studies indicated that AMF observably upregulated the genes' expressions (i.e., CsCAT and CsSOD) in both the 0 and 100 mmol/L NaCl seedlings. Meanwhile, the 100 mmol/L NaCl seedlings represented markedly lower antioxidant enzyme activities (i.e., SOD, CAT, and POD) and gene expressions (i.e., CsSOD and CsCAT) than the non-NaCl seedlings, irrespective of AMF inoculation. These results imply that AMF has a positive role in strengthening salt tolerance and on the quality of fresh tea leaves. [ABSTRACT FROM AUTHOR]

Phytoremediation of heavy metals (HMs) is an efficient methodology to remove toxic metals from the soil. On the other hand, arbuscular mycorrhizal fungi (AMF) are utilized as biological fertilizers as they improve root expansion, nutrient uptake, shoot growth, and plant biological performance. In this study, the effect of AMF inoculation on the morphological traits, macro- and micronutrient contents, essential oil content (EOC), and essential oil yield (EOY) of lavender (Lavandula angustifolia L.) was investigated, under HM (Pb and Ni) stress in greenhouse conditions. The performed treatments were as follows: AMF (Funneliformis mosseae) inoculation (5 g kg−1 soil), and HM stress, including Pb (150 and 225 mg kg−1 soil from Pb(NO3)2) and Ni (220 and 330 mg kg−1 soil from Ni(NO3)2). The controls were the absence of AMF and HM treatments. The results showed that the contamination with Pb and Ni decreased plant height, branch number, fresh and dry weights of shoots and roots, and P, K, Mg, Fe, Zn, and Mn contents. At the same time, AMF inoculation modulated the adverse effects of Pb and Ni treatments. AMF inoculation and lower concentrations of Pb and Ni increased the EOC and EOY of lavender plants, whereas the higher levels of HMs reduced the morphobiometric traits. AMF inoculation increased the Pb and Ni contents in roots. The treatment with Pb at 220 mg kg−1 led to a higher stress effect than that of Ni treatment. In conclusion, the results recommend AMF inoculation as a helpful procedure to improve the growth responses and EOY of lavender in environments polluted with the tested HMs and suggest that AMF inoculation is potentially efficient in mitigating HM stress effects. [ABSTRACT FROM AUTHOR]

Biofertilizers, such as arbuscular mycorrhiza fungi (AMF) and seaweed extract (SWE), have been effective in environmental and agricultural ecosystems. In this study, the effects of AMF, SWE, and their co-application were assayed on the growth and antioxidant potential of lettuce plants. The experiment was conducted as a factorial based on a completely randomized design with two factors and four replications under greenhouse conditions. The first factor was AMF (Glomus mosseae) at two levels consisting of AMF application (20 g pot−1), and without using AMF; and the second factor was SWE foliar spraying (Ascophyllum nodosum) at 0.5, 1.5 and 3 g L−1 concentration. The results revealed that the highest root colonization (85%) belonged to AMF and SWE (3 g L−1) × AMF; the lowest colonization rate (65%) was observed for AMF × SWE (0.5 g L−1) treatment. The highest growth parameters (leaf number, shoot and root fresh weight, head diameter), biochemical traits (total soluble proteins, carbohydrates content) and TAA, total antioxidant activity by FRAP method and ascorbic acid, total phenolics, and flavonoids content were obtained with the co-applications. Therefore, the best results of the evaluated traits were achieved with AMF × SWE (3 g L−1). The TAA value was increased three-fold compared to the control. Total phenolics and flavonoids content were 2.24 and 6.59 times higher than the control, respectively. On the other hand, leaf dry weight was decreased with the further growth of the plants. Overall, the co-application of AMF with SWE can be recommended to producers as an alternative and environment-friendly strategy to improve the qualitative and quantitative traits of the lettuce crop. [ABSTRACT FROM AUTHOR]

In acidic soils with manganese (Mn) toxicity, arbuscular mycorrhizal fungi (AMF) can improve plant host growth by enhancing nutrition and protecting against environmental stress. The intact extraradical mycelium (ERM) of AMF is able to survive Mediterranean summer conditions and provide an earlier colonization of winter crops. This study evaluated if summer season conditions hindered the beneficial effects of wheat colonization by the intact ERM associated with a native plant, in acidic soil. Wheat was grown in soil with intact or disrupted ERM associated with Ornithopus compressus (ORN), developed for 7 or 24 weeks, to simulate ERM summer survival. The activity of antioxidant enzymes was determined, and the quantitative analysis of Mn and macronutrients was performed by inductively coupled plasma mass spectrometry (ICP-MS), in wheat shoots and respective subcellular fractions. Wheat colonization by intact ERM decreased shoot Mn concentration but increased the proportion of Mn in the apoplast. Overall, antioxidant enzymatic activity decreased but the proportion of Mn-superoxide dismutase activity over the remaining isoforms increased, suggesting its important role in the AMF-mediated mitigation of Mn toxicity. Summer conditions did not substantially reduce the benefits provided by ORN ERM. A no-till strategy allied to the development of native microbiota can contribute to the sustainable optimization of acidic soil use. [ABSTRACT FROM AUTHOR]

Plant-associated microorganisms play an important role in agricultural production. Although various studies have shown that single microorganisms can exert beneficial effects on plants, it is increasingly evident that when a microbial consortium—two or more interacting microorganisms—is involved, additive or synergistic results can be expected. This occurs, in part, due to the fact that multiple species can perform a variety of tasks in an ecosystem like the rhizosphere. Therefore, the beneficial mechanisms of plant growth stimulation (i.e., enhanced nutrient availability, phytohormone modulation, biocontrol, biotic and abiotic stress tolerance) exerted by different microbial players within the rhizosphere, such as plant-growth-promoting bacteria (PGPB) and fungi (such as Trichoderma and Mycorrhizae), are reviewed. In addition, their interaction and beneficial activity are highlighted when they act as part of a consortium, mainly as mixtures of different species of PGPB, PGPB–Mycorrhizae, and PGPB–Trichoderma, under normal and diverse stress conditions. Finally, we propose the expansion of the use of different microbial consortia, as well as an increase in research on different mixtures of microorganisms that facilitate the best and most consistent results in the field. [ABSTRACT FROM AUTHOR]

The herbaceous grafting of fruiting vegetables is considered a toolbox for safeguarding yield stability under various distresses and for improving fruit quality. Inoculation with arbuscular mycorrhiza (AM) fungi seems also to be an efficient tool for increasing the assimilation, uptake and translocation of macroelements and microelements, for modulating plant secondary metabolism and for overcoming several forms of plant distress. The present work evaluated the combined effect of grafting the "Birgah" (B) eggplant onto its wild/allied relatives' rootstocks (Solanum torvum (T), S. macrocarpon (M) and S. paniculatum (P)) and AM fungi (R. irregularis) on the yield, fruit quality, nitrogen use efficiency, mineral profile, and nutritional and functional quality. The B/T, B/M and B/P grafting combinations significantly increased the marketable fruit and fruit number compared with those in the ungrafted control. Furthermore, irrespective of the grafting combinations, AM fungi significantly enhanced the marketable fruit, fruit number and nitrogen use efficiency (NUE) by 13.3%, 12.7% and 13.3%, respectively compared to those in the untreated control. Exposing the B/T and B/P grafted plants to the +AM treatment significantly increased the ascorbic acid contents by 17.2% and 10.4%, respectively, compared with those in the ungrafted control. Fruits from the combination B/P × +AM had a higher chlorogenic acid content than fruits from the ungrafted control plots. Finally, the B/T × +AM and B/P × +AM combinations decreased glycoalkaloids by 58.7% and 63.7%, respectively, compared with those in the ungrafted control, which represents a highly important target for eggplant fruit healthiness. [ABSTRACT FROM AUTHOR]

A potted experiment was carried out to evaluate the effect of an arbuscular mycorrhizal fungus (AMF), Acaulospora scrobiculata, on peach seedlings grown in non-replant (NR) and replant (R) soils, to establish whether AMF inoculation alleviated soil replant disease through changes in physiological levels and relevant gene expression. After 15 weeks of mycorrhization, root mycorrhizal colonization was heavily inhibited by R treatment versus NR treatment. AMF plants under NR and R soil conditions displayed significantly higher total plant biomass than non-AMF plants. AMF inoculation significantly increased root sucrose and fructose concentrations and root catalase, peroxidase, polyphenol oxidase, and phenylalanine ammonialyase activities under R conditions. Likewise, salicylic acid, jasmonic acid, chitinase, total soluble phenol, and lignin concentrations in roots were significantly higher in AMF than in non-AMF seedlings grown in R soil. Over-expression of PpCHI, PpLOX1, PpLOX5, PpAOC3, PpAOC4, and PpOPR2 in roots was observed in AMF-inoculated seedlings, as compared to that of non-AMF-inoculated seedlings grown in R soils. Thus, mycorrhizal fungal inoculation conferred a greater tolerance to peach plants in R soil by stimulating antioxidant enzyme activities, disease-resistance substance levels, and the expression of relevant genes. [ABSTRACT FROM AUTHOR]

Iris germanica L. is an ornamental and medicinal plant used since ancient times for their rhizomes, still utilized today to obtain orris butter highly valued in perfumery. Iris germanica presents special root adaptations, which confers certain tolerance to water and salt stress, making it a good option in the context of the current climate trend. Aim of this study was to prospect the potential for biofortification of rhizomes using commercial arbuscular mycorrhizae (AM) application in field conditions for six Iris germanica cultivars. Plants presented Paris-type AM colonization. Rhizome samples collected after nine months from treatment and maturated, presented FT-IR (fourier transform infrared spectroscopy) spectra variation between experimental variants. Presence of the main metabolites in rhizome could be confirmed based on literature. Screening focused on two rhizome quality markers: carbohydrates, which influence plant development, and fatty acids, which are extractable from rhizome. Results suggest potential to enhance their accumulation in certain cultivars, such as 'Pinafore Pink' following AM application. [ABSTRACT FROM AUTHOR]