Claroideoglomus Etunicatum Research Articles

Claroideoglomus etunicatum and Pantoea dispersa significantly enhance growth and nutrition of broom grass

Claroideoglomus etunicatum and Pantoea dispersa significantly enhance growth and nutrition of broom grass

Analysis of Arbuscular Mycorrhizal Fungal Inoculant Benchmarks.

Growing evidence showed that efficient acquisition and use of nutrients by crops is controlled by root-associated microbiomes. Efficient management of this system is essential to improving crop yield, while reducing the environmental footprint of crop production. Both endophytic and rhizospheric microorganisms can directly promote crop growth, increasing crop yield per unit of soil nutrients. A variety of plant symbionts, most notably the arbuscular mycorrhizal fungi (AMF), nitrogen-fixing bacteria, and phosphate-potassium-solubilizing microorganisms entered the era of large-scale applications in agriculture, horticulture, and forestry. The purpose of this study is to compile data to give a complete and comprehensive assessment and an update of mycorrhizal-based inoculant uses in agriculture in the past, present, and future. Based on available data, 68 mycorrhizal products from 28 manufacturers across Europe, America, and Asia were examined on varying properties such as physical forms, arbuscular mycorrhizal fungal composition, number of active ingredients, claims of purpose served, mode of application, and recommendation. Results show that 90% of the products studied are in solid formula—powder (65%) and granular (25%), while only 10% occur in liquid formula. We found that 100% of the products are based on the Glomeraceae of which three species dominate among all the products in the order of Rhizophagus irregularis (39%), Funneliformis mosseae (21%), Claroideoglomus etunicatum (16%). Rhizophagus clarus is the least common among all the benchmark products. One third of the products is single species AMF and only 19% include other beneficial microbes. Of the sampled products, 44% contain AMF only while the rest are combined with varying active ingredients. Most of the products (84%) claimed to provide plant nutrient benefits. Soil application dominates agricultural practices of the products and represents 47%. A substantial amount of the inoculants were applied in cereal production. Recommended application doses varied extensively per plant, seed and hectare. AMF inoculant seed coating accounted for 26% of the products’ application and has great potential for increased inoculation efficiency over large-scale production due to minimum inoculum use. More applied research should also be conducted on the possible combination of AMF with other beneficial microbes.

Farklı Mikoriza Türleri, Kompost ve Fosfat Kayacı Uygulamalarının Sorgum Bitkisinin Gelişimine Etkileri

Bu çalışma, farklı mikoriza türleri aşılaması ile birlikte farklı dozlarda kompost ve fosfat kayacı uygulamalarının sorgum bitkisinin gelişimi ve besin elementleri alımına olan etkilerini belirlemek amacıyla yapılmıştır. Denemede kompost dozları 0, 20, 40 g kompost/kg toprak, fosfat kayacı dozları 0, 2, 4 g fosfat kayacı/kg toprak olarak uygulanmış, mikoriza türleri olarak; Funnelformis mosseae, F. caledonius, Claroideoglomus etunicatum, Rhizophagus clarus, doğal ve kokteyl (karışım) kullanılmıştır. Hasat sonunda kök ve kök üstü aksam kuru madde üretimleri, fosfor (P) ve çinko (Zn) konsantrasyonları ve mikorizal kök infeksiyonu analizleri yapılmıştır. Araştırma bulgularına göre, mikoriza aşılaması sorgum bitkisinin kök ve kök üstü aksam kuru madde üretimine, P, Zn ve kök infeksiyonuna fosfat kayacı ve kompost uygulamalarına göre daha fazla oranda etki etmiştir. En etkili mikoriza türü olarak F. caledonius ön plana çıkmaktadır. Kompost uygulamalarında 20 ve 40 g/kg toprak doz uygulamaları etkin bulunur iken, fosfat kayacında ise yetiştirme süresinin kısalığı nedeniyle fosfat kayacının yeterince çözünemediği kanısına varılmıştır.

Application of soil biofertilizers to a clayey soil contaminated with Sclerotium rolfsii can promote production, protection and nutritive status of Phaseolus vulgaris

Sclerotium rolfsii is a soil-borne fungus that causes big losses in productivity of various plant species including Phaseolus vulgaris L. The objectives of this study were to (1) evaluate the impacts of Sclerotium rolfsii on growth and production of common bean plants, (2) determine the effects of Sclerotium rolfsii on nutritive contents of beans, and (3) test the efficacy of bio-inoculants on suppressing plant infection with Sclerotium rolfsii. To fulfill these objectives, we used a coupled pot and field experimental approaches during two growing seasons. Common beans were inoculated with either arbuscular mycorrhizal fungi (Claroideoglomus etunicatum), Saccharomyces cerevisiae, or Trichoderma viride solely or in different combinations. Non-inoculated plants and fungicide treated ones were considered as reference treatments. Throughout these experiments, minimal amounts of rock phosphate were added during soil preparation for bio-inoculated treatments, while the non-inoculated reference treatments received a full dose of P as calcium superphosphate. Results revealed that all tested bioinoculants significantly raised the activities of plant defense enzymes i.e. chitinase, peroxidase and polyphenoloxidase as compared to non-inoculated control. Likewise, pre-, post- and plant survival percentages significantly increased due to these bio-inoculations. Increased survival percentages were attributed to the concurrent increases in uptake of N, P and Zn nutrients by plants treated with bioinoculants. In this concern, plant nutrients uptake was higher in combined than single bio-inoculant treatments. Moreover, the uptake values of plant nutrients owing to the combined bio-inoculants were higher than the corresponding ones achieved due to fungicide treatment. In conclusion, application of the tested bio-inoculants, especially the combined ones can be considered an eco-friendly approach that not only enhances plants resistance against infection with Sclerotium rolfsii but also improves plant nutritive status.

Mycorrhizas promote P acquisition of tea plants through changes in root morphology and P transporter gene expression

Tea (Camellia sinensis (L.) O. Kuntze) is predominantly grown in acidic soils with severe limitations of P-nutrition. The present study evaluated the effects of an arbuscular mycorrhizal (AM) fungus, Claroideoglomus etunicatum, on root morphology, leaf and root P concentration, phosphatase activity in soils and roots, and the relative expression of root P transporter genes (PT1 and PT4) in Camellia sinensis ‘Fuding Dabaicha’ seedlings in sands under two levels of P viz., 0.5 μM (P0.5) and 50 μM (P50) through Hoagland solutions (pH 4.2) for 24 weeks. Under both P0.5 and P50 conditions, AM seedlings displayed a higher growth performance (shoot biomass, root biomass, and plant height), root morphology (total length, taproot length, 2nd- and 3rd-lateral root number, and volume), and root-hair length, but lower root-hair density than non-AM seedlings. Mycorrhizal inoculation significantly increased root P concentrations in P0.5 and P50 and leaf P concentrations in P0.5 over non-mycorrhizal treatment. The AM seedlings recorded considerably higher soil acid, neutral, and total phosphatase activity under P0.5 treatment, and soil neutral and total phosphatase activity under P50 treatment, compared with the non-AM seedlings. Root acid phosphatase activity was reduced due to mycorrhization at both of P0.5 and P50. AM fungal inoculation up-regulated the relative expression of root CsPT1, while down-regulated the CsPT4 expression in P0.5 and P50 treatments. It was concluded that AM fungal inoculation significantly promoted P acquisition capacity of tea plants, especially in roots through improving root growth and enhancing soil acid phosphatase activity and root CsPT1 expression.

Nodulation and biological nitrogen fixation in soybean (Glycine max L.) as influenced by phosphorus fertilization and arbuscular mycorrhizal inoculation

Abstract Arbuscular mycorrhizal fungi (AMF) can be used to promote the productivity of legumes on phosphorus- (P) deficient soils. The present study investigates the inoculation effects of three AMF species (Funneliformis mosseae, Rhizophagus intraradices, and Claroideoglomus etunicatum) and the control (uninoculated) on nitrogen fixation efficiency and growth performance of tropical soybean cultivar (TGx1448-2E) under varying P fertilizer rates (0, 20, and 40 kg P2O5 ha−1) in a derived savannah of Nigeria. The results showed that shoot and root dry matter, number of nodules, relative ureide abundance (RUA), nitrogen derived from atmosphere (Ndfa), total N fixed, shoot P uptake, grain, and biomass yield significantly increased with AMF inoculation, with better performance observed in plants inoculated with Rhizophagus intraradices and Funneliformis mosseae compared to Claroideoglomus etunicatum. Similarly, the soybean growth variables, P uptake, and nitrogen fixation activities increased with increasing P application rates. Conversely, AMF root colonization significantly reduced with increasing P rate. Interaction of AMF inoculation and P rates significantly influenced soybean growth and nitrogen fixation. R. intraradices inoculation with 20 kg P2O5 ha−1 resulted in the highest amount of RUA, Ndfa, N fixed, and grain yield. It could be concluded from this study that R. intraradices with moderate P rate could be used to enhance nodulation, nitrogen fixation, and soybean yield in P-deficient soils.

Efficacy Of Indigenous Arbuscular Mycorrhizal Fungi And Liquid Organic Fertilizer For Promoting The Vegetative Growth Of Soybean Plants (Glycine max L.) On Ultisols

Utilization of ultisols in Southeast Sulawesi may be approached by inoculating viable arbuscular mycorrhizal fungi (AMF) exposing plant growth-promoting activities to the growth of native economical plants. This study investigated a combination of AMF and liquid organic fertilizers from coconut husks to improve the growth of soybean plants grown on ultisols as one of the potential marginal soils in the region. The coconut husk served as an abundant, cheap, yet potential source for the preparation of liquid organic fertilizers. This study used two factorial design with four treatment levels. The first factor was designed for different AMF species (10 g/pots): control (M0), Acaulospora delicata (M1), Septoglomus constrictum (M2), and Claroideoglomus etunicatum (M3) while the second factor was designed for different concentration of liquid organic fertilizer (mL/pots): control (P0), 150 mL/pots (P1), 200 mL/pots (P2), and 250 mL/pots (P3). Based on ANOVA results, the independent application of AMF species and liquid organic fertilizers gave significant results in regards to the experimental variables such as plant height, number of leaves, leaf area, and stem diameter. The best combination of treatment was observed in the treatment using Septoglomus constrictum with the concentration of liquid organic fertilizer of 250 mL (M2P3) to yield the highest growth performance of soybean plants on ultisols.

Effect of Mycorrhizal Inoculation and Irrigation on Biological Properties of Sweet Pepper Rhizosphere in Organic Field Cultivation

The aim of the study was to evaluate the influence of mycorrhizal fungi (MF) and irrigation on biological properties of sweet pepper rhizosphere in organic field cultivation. For this purpose, MF were applied to plants in the form of commercial mycorrhizal inoculum (Rhizophagus aggregatus, R. intraradices, Claroideoglomus etunicatum, Endogone mosseae, Funneliformis caledonium, and Gigaspora margarita) and irrigation according to the combinations: mycorrhized plants (PM), mycorrhized and irrigated plants (PMI), and irrigated plants (PI). Plants without MF and irrigation served as the absolute control (P). The study used classic and molecular techniques, assessing catalase activity, biodiversity of soil microorganisms (soil DNA analysis), and the Community-Level Physiological Profiles (CLPP) analysis using Biolog EcoPlates. The highest catalase activity was recorded in the control and mycorrhized soil sample. The highest total number of bacteria was noted in the rhizosphere of control plants (P) and irrigated plants, while the lowest number in the rhizosphere of mycorrhized and irrigated plants. Plant irrigation contributed to the increase in the total number of fungi in the rhizosphere. The rhizospheric soil of PM and PMI were characterized by the highest utilization of amines, amides, and amino acids, whereas the lowest level of utilization was detected in the P and PI rhizospheres. The highest biodiversity and metabolic activity were observed in the rhizospheres from the PMI and PM samples, whereas lower catabolic activity were recorded in the P and PI rhizospheres. The mycorrhization of crops improved the biological properties of the rhizosphere, especially under conditions of drought stress.

Morpho-physiology and Pht1 gene expressions in native maize plants with AM fungi and phosphorus

Maize is a crop important worldwide, but its production is limited to phosphorus availability in soil. Plants form a symbiotic association to improve their nutrition with arbuscular mycorrhizal fungi (AMF), which increase to absorption phosphorus (P) and the expression of transporters of the family Pht1. Few studies have focused on native maize plants and AMF. Thus, the objective of this study was to determine the morpho-physiological response and expression of phosphate Pht1 transporters in two native maize plants inoculated with Claroideoglomus etunicatum and P concentrations. The height, leaf area, dry biomass, CO2 assimilation rate, stomatal conductance, transpiration rate, intercellular CO2, water potential, greenness index, total chlorophyll, and ZEAma; Pht1;3 and ZEAma; Pht1;6 transporter expressions in maize plants under P (0.01 and 1 mM) concentrations were evaluated. The results showed that each native maize plant had a differential response in morpho-physiology and transporter expressions when they were inoculated with AMF and P. The response of maize plant was related with its genotype and phenotype plus environmental factor that influenced the AMF-host interaction, mycorrhizal colonization and soil nutrient absorption.

Alta presencia de cadmio resulta en baja diversidad de hongos formadores de micorrizas arbusculares asociados a cacao (Theobroma cacao L.)

Los hongos formadores de micorrizas arbusculares (HFMA) son simbiontes obligados presentes en la rizósfera de plantas de cacao y la diversidad de sus comunidades se modifica, dependiendo de diversos factores como la presencia de cadmio (Cd) en el suelo. La persistencia de HFMA en suelos enriquecidos naturalmente con Cd podría ser un indicador de su capacidad para tolerar esta condición. Esta investigación caracterizó la estructura de la comunidad de HFMA locales presentes en la rizósfera de plantas de cacao en dos suelos con baja (B-Cd: 0,1 mg kg-1) y alta (A-Cd: 20,9 mg kg-1) concentración de Cd. Esporas de HFMA se identificaron mediante claves taxonómicas y su abundancia, riqueza y diversidad se determinó en muestras de suelo originales y después de su multiplicación mediante cultivos trampa. Las comunidades de HFMA se compararon usando análisis de componentes principales (ACP) e índices de diversidad alfa y beta. Los resultados indican que A-Cd presentó valores significativamente menores de abundancia (21 %), riqueza (20 %) y diversidad (11 %) de morfoespecies de HFMA con respecto a B-Cd. Las dos comunidades de HFMA presentaron cinco de siete géneros en común, pero solo cuatro de las 23 morfoespecies descritas se encontraron en ambas comunidades.El análisis de diversidad beta y el ACP determinaron baja similaridad y tasa de recambio entre las comunidades de HFMA. La dominancia de Diversispora spurca, Rhizoglomus sp. yClaroideoglomus etunicatumen A-Cd sugiere que estas morfoespecies son estrés-tolerantes y candidatos potenciales para el desarrollo de estrategias de mitigación en suelos con Cd.

Performance of tomato and lettuce to arbuscular mycorrhizal fungi and Penicillium pinophilum EU0013 inoculation varies with soil, culture media of inoculum, and fungal consortium composition

The context-dependent nature of plant-microbe interaction in the rhizosphere is of significance in terms of the consistency of beneficial microbe effects in inoculated plants. We performed a series of experiments testing the effect of inoculation with arbuscular mycorrhizal fungi (AMF) and a root-associated fungus, Penicillium pinophilum EU0013, on the growth and root colonization of tomato and lettuce. Three AMF species (Rhizophagus irregularis, Rhizophagus intraradices, and Claroideoglomus etunicatum) and Penicillium (inoculum from corn and wheat media) were used in AMF-plant, Penicillium-plant, and AMF-Penicillium-plant partnerships. In lettuce, we also tested C. etunicatum interaction with Penicillium under different soils (river sand, commercial soil, and river sand + commercial soil). Penicillium pinophilum EU0013 showed phosphate solubilization, siderophore and organic acid production traits in in-vitro assays. In tomato and lettuce, mycorrhizal and Penicillium root colonization were increased during co-inoculation compared to single AMF or Penicillium treatment, indicating that a reciprocal fungal stimulation occurred during AMF-endophyte interaction in both hosts. In tomato, the inoculation with only Penicillium (from wheat medium) or in combination with AMF, significantly improved host weights. In lettuce, fresh weight was significantly improved when Penicillium from corn medium was used in combination with C. etunicatum. However, when the same AMF-Penicillium consortium was tested using Penicillium from wheat media, co-infection stress in the form of retarded growth, wilting of leaves and mortality occurred, depending on the soil. The pattern of negative effects could be rapid and transient, where wilting, slow growth, mortality, and recovery occurred (in river sand), or gradual and persistent where there was slower growth but no mortality (as in commercial and mixed soil). Target host, soil, culture media of inoculum and fungal consortium composition are important considerations in the exploitation of AMF and Penicillium pinophilum EU0013 for improving vegetable growth.

Crescimento de milho crioulo cultivado com fungos micorrízicos arbusculares

Os fungos micorrízicos arbusculares realizam simbiose com a maioria das espécies de plantas e podem influenciar no crescimento, na resistência à seca e também reduzir o consumo de fertilizantes minerais, a depender da interação com a planta hospedeira. O objetivo deste trabalho foi avaliar a colonização micorrízica e a sua interação no crescimento do milho crioulo. O delineamento experimental utilizado foi inteiramente casualizado composto por quatro tratamentos: controle (sem inoculante micorrízico) e três isolados micorrízicos arbusculares (UFLA351 - Rhizoglomus clarum, UFLA372 - Claroideoglomus etunicatum e UFLA401 - Acaulospora morrowiae) com cinco repetições. A colonização micorrízica do milho crioulo é arbuscular-vesicular com o emprego dos isolados UFLA351, UFLA372 e UFLA401. A alta taxa de colonização micorrízica do milho crioulo não garante incremento na biomassa, mas pode influenciar na emissão das inflorescências. O milho crioulo foi responsivo à inoculação do isolado UFLA372.

Micorrhizal biotechnology as an alternative to potentialize the strawberry quality

The need to develop and use biotechnology tools to improve management and nutritional techniques in strawberry cultivation are increasing. Based on this, the objective of this study was to test if the mycorrhizal inoculation changes the agronomic and qualitative performance of strawberry fruits. The strawberry daughters plants used were of the cultivar Camarosa. The study was carried out in an agricultural greenhouse, Horticulture Sector of the Faculty of Agronomy and Veterinary Medicine (FAMV) of UPF, in the city of Passo Fundo, Rio Grande do Sul (RS), Brazil. The experiment was developed and maintained from June to December 2015. The treatments consisted of five inoculum: T1 = no inoculum (control); T2 = Acaulospora morrowiae; T3 = Rhizophagus clarus; T4 = mycorrhizal community; T5 = Claroideoglomus etunicatum. The experimental design was a randomized block with four replicates. Each plot consisted of a bag containing 6 plants spaced 0.15 mx 0.15 m. In the pits of the plants, it was applied, with the aid of syringe and water, about 70 infective propagules of the tested inocula. During the conduction of the experiment the temperature and photosynthetically active radiation (PAR) were monitored in the culture environment. It was evaluated the agronomic and qualitative performance of the fruits and the percentage of mycorrhizal colonization of the plants roots. The data were submitted to analysis of variance and the differences between means were compared by the Tukey test at 5% of probability error. The cultivar Camarosa produced more fruits in October. In September, the month before the one with the best agronomic performance, the mean temperature was 17.7 ºC. The mean PAR recorded in the growing environment was low in relation to crop requirements, throughout the growing period. Fruits produced by plants inoculated with A. morrowiae presented higher values of TSS/TTA ratio in September and October. The percentage of mycorrhizal colonization varied from 26.2% for A. morrowiae to 46.2% for R. clarus. The inoculation of arbuscular mycorrhizal fungi does not alter the production of strawberry fruits. However, when the plants are inoculated with A. morrowiae there is an improvement in the fruit flavor.

Diversity of mycorrhizal fungi and soil indicative species in coastal plantations of northeast Brazil

The aim of this work was to evaluate arbuscular mycorrhizal (AM) fungi as soil indicators and the mycorrhization of native and exotic tree species planted in the Acarau basin, a transition area from the coast to the Brazilian semiarid region. Plots with 6-year-old trees of four native and three non-native species as well as one non-forested area were evaluated in terms of the diversity of AM fungi in the mycorrhizosphere and the root colonization by AM and ectomycorrhizal (EcM) fungi. Twenty-four AM fungi were identified; Claroideoglomus etunicatum, Glomus sinuosum, Paraglomus albidum, Acaulospora laevis, and Acaulospora brasiliensis were abundant in the forest soil. Diversity, dominance, evenness and richness indices of AM fungi were higher in plots with native trees. All root samples were colonized by AM fungi and only Anadenanthera colubrina, Acacia mangium, Casuarina equisetifolia and Eucalyptus urophylla formed associations with EcM fungi. Acaulospora morphotypes served as soil indicators for coverings with the native species Astronium fraxinifolium and Colubrina glandulosa. Exotic species may favor the proliferation of rarer AM fungi. These fungi–plant relationships may be important in the management of forest systems, and the evidence with mycorrhizal associations allows the inclusion of Brazilian species in tropical reforestation.

Colonization with arbuscular mycorrhizal fungi mitigates cold stress through improvement of antioxidant defense and accumulation of protecting molecules in eggplants

Eggplant (Solanum melongena L.) is a thermophilic species susceptible to cold stress. The potential of arbuscular mycorrhizal fungi (AMF) for the amelioration of cold stress in this species has not been investigated so far. This study was conducted to examine some of the physiological functions through which the AMF colonization may improve cold stress tolerance in this species. Plants were inoculated with four AMF species (Funneliformis mosseae, Claroideoglomus etunicatum, Rhizophagus irregularis, and Diversispora versiformis), grown for three weeks under growth chamber conditions, and then treated with three different temperatures (25 °C, 15 °C, and 5 °C) for one week. Results showed that despite the reduction in root colonization, AMF were able to alleviate cold stress in the eggplants by improving photochemical reactions, activating antioxidant defense systems, accumulating protecting molecules, and reducing membrane damages. Cold stress mitigation through AMF was mediated by H2O2 as a priming molecule accumulated upon mycorrhization prior to cold stress. A comparison of four AMF species showed that D. versiformis was less effective than the other three fungal species in alleviating cold stress due to the inability to accumulate the protecting molecules, particularly proline and free phenolics. Our results revealed that AMF inoculation with suitable fungal species is an effective strategy for alleviating cold stress in eggplants.

Arbuscular mycorrhizal fungus identity modulates growth effects of endophyte-infected grasses on neighboring plants.

Endophytes of grasses have been reported to affect the colonization by arbuscular mycorrhizal fungi (AMF) not only of their dual host plant but also of neighboring non-endophyte-infected plants. However, studies investigating the impact of AMF identity on the effects of endophyte-infected grasses on neighboring plants are rare. In this study, we investigated the influence of Leymus chinensis litter type (NL, no litter; E-, endophyte-free litter; E-E+, half E+ and half E- litter; E+, endophyte-infected litter) on Stipa krylovii growth with different AMF species (Claroideoglomus etunicatum, CE; Funneliformis mosseae, FM; Claroideoglomus claroideum, CC; Rhizophagus intraradices, RI). The results showed that the root biomass of S. krylovii tended to decrease with the increase of E+ litter in the mycorrhiza-free treatment. With AMF inoculation, the effects of E+ litter on the AMF colonization rate and root biomass of S. krylovii varied with AMF species. Structural equation modeling (SEM) showed E+ litter could modulate the growth of S. krylovii indirectly via changes in AMF colonization rate, but this effect was related to AMF species.

Acaulospora longula Increases the Content of Phenolic Compounds and Antioxidant Activity in Fruits of Libidibia ferrea

Background: Several countries have made an association that how conventional and traditional medicines support the rational use of medicinal plants in different treatments. Brazil has stimulated the cultivation of and the development of the studies of Libidibia ferrea, a plant with medicinal properties, which are provided by the presence of bioactive compounds in its several parts, such as fruits. The synthesis of these biomolecules may increase with Arbuscular Mycorrhizal Fungi (AMF) inoculation. However, there have been no previous reports about the optimization in the production of biomolecules in the fruits of mycorrhizal L. ferrea. Objective: The aim of this study was to define the potential advantages of inoculation with AMF by increasing the production of biomolecules and antioxidant activity in fruits of mycorrhizal L. ferrea. Methods: The phytochemical and mycorrhizal analyses occurred after 32 months of transplanting to the field and the plants were inoculated or not with Acaulospora longula, Claroideoglomus etunicatum and Gigaspora albida and then by transplanting the seedlings to the field. Results: Compared to those from the control treatment, the concentration of phenols and tannins in the fruits of L. ferrea inoculated with A. longula increased 26.4% and 39.8% (p <0.05), respectively. The fruits also had higher antioxidant activity. In contrast, the concentration of phosphorus in the fruits of L. ferrea inoculated with A. longula and C. etunicatum was not incresead. Because the concentration of phosphorus in fruits was verified in this study. Conclusion: Mycorrhization increased the concentration of biocompounds and antioxidant activity in the fruits of L. ferrea, which is of great interest to the herbal medicine industry.

Response of growth and drought tolerance of Acacia seyal Del. seedlings to arbuscular mycorrhizal fungi

Considering the improvement of acacia species growth in arid and semi-arid environment, a pot experiment was conducted to evaluate the role of arbuscular mycorrhizal fungi (AMF); Funneliformis mosseae (syn. Glomus mosseae), Rhizophagus intraradices (syn. Glomus intraradices) and Claroideoglomus etunicatum (syn. Glomus etunicatum) on growth and drought tolerance of Acacia seyal Del. seedlings under drought cycles (7, 14, 21 and 28 days). AMF-inoculated seedlings showed a clear colonisation percentage (36–68%). AMF treatment significantly improved seedlings shoot and root growth under all drought cycles compared to non-AMF control seedlings. Moreover, AMF treatment enhanced seedlings drought resistance by increasing root surface area (root length increased by 483.76% and root tips number increased by 1 463.94% under 28 days of drought cycle), there was a strong linear relation between proline accumulation, AMF and drought stress (proline content decreased in treated seedlings by 31.3% and 14.3% and increased by 97.5% and 80.4% in untreated seedlings under drought cycles of 21 and 28 days, respectively). In conclusion, the AMF inoculation improved growth and enhanced drought tolerance of A. seyal seedlings and can be used as a natural biostimulator for acacias seedlings establishment in arid areas.

Mitigation of water deficit stress in Dracocephalum moldavica by symbiotic association with soil microorganisms

Symbiotic association with soil microorganisms (plant growth-promoting rhizobacteria (PGPR) and/or arbuscular mycorrhizal fungus (AM)) can help plants to cope with drought stress. The goal of the present study was to consider the effects of Micrococcus yunnanensis (PGPR) and Claroideoglomus etunicatum (AM) under drought stress on growth, mineral nutrients uptake, and secondary metabolites of D. moldavica, as a sensitive plant to water deficit. Experiments were carried out as factorial completely randomized design consisting of three factors, PGPR, AM, and irrigation levels (100, 85, 70, 55, 40, and 25 % field capacity). The results showed that PGPR and AM stimulated plant growth significantly and increased photosynthetic pigment contents of leaves. Higher uptake of nutrient elements partly improved plant growth and dry matter production upon symbiotic associations. Despite a significant increase in the soluble sugars and proline contents under water deficit stress, symbiosis significantly decreased the amounts of those compounds. Drought stress alone elevated plant antioxidant capacity and total phenolic content, but they were decreased in plants inoculated with PGPR and AM. Also, co-inoculation increased the contents of hesperetin, eugenol, p-coumaric acid, and these effects were more pronounced under moderate drought stress than other conditions for hesperetin and p-coumaric acid accumulation. Significantly, higher content of rosmarinic acid was found under drought stress, but inoculations significantly decreased the concentrations of this compound. Overall, these results showed a successful coexistence of soil microorganisms (PGPR and AM) with D. moldavica alleviates the harmful effects of drought stress through higher mineral nutrient uptake as well as secondary metabolites and photosynthetic pigments contents.

Nematophagous and endomycorrhizal fungi in the control of Meloidogyne incognita in soybean

The root knot nematode (Meloidogyne spp.) is a widely distributed phytoparasite and causes production losses in soybeans. Therefore, the aim of the present study was to evaluate the isolates of Purpureocillium lilacinum (Simbiose®), Claroideoglomus etunicatum and Rhizophagus clarus as possible biocontrol agents for Meloidogyne incognita. The greenhouse treatments consisted of six distinct formulations of fungal isolates: T1 - Witness; T2 - P. lilacinum (100 μl−1); T3 - C. etunicatum (23.5 mL−1); T4 - R. clarus (23.5 mL−1); T5 - P. lilacinum (100 μl−1) + C. etunicatum (23.5 mL−1); T6 - P. lilacinum (100 μl−1) + R. clarus (23.5 mL−1) with five repetitions each. The nematophagous fungus was applied in liquid suspension and the inoculums of arbuscular mycorrhizal fungi (AMFs) composed of propagules (spores, hyphae, colonized root fragments) in the sowing furrow. The sowing of two soybean seeds susceptible to M. incognita was carried out in 2L pots with a mixture of sand and earth in proportion (3:1). The inoculation of 2000 eggs and eventual juveniles of the second stage (J2) of M. incognita per plant was carried out in sequence. Sixty-five days after inoculation, the plants were removed to evaluate the vegetative, mycorrhizal and nematological variables. The data were submitted to a media comparison test with a 5% probability of error. The biocontrol potential of these fungi becomes an agricultural alternative for the biological management of Meloidogyne spp., as well as for the sustainability of agriculture and biological and biotechnological production.