Fungal Inoculation Research Articles

Isolation, Identification, and Application of Endophytic Fungi from Lavandula stoechas L.: Mitigating Salinity Stress in Hydroponic Winter Cereal Fodder

Soil and irrigation water salinity is a growing global problem affecting farmland, due to poor agricultural practices and climate change, leading to reduced crop yields. Given the limited amount of arable land and the need to boost production, hydroponic systems offer a viable solution. Additionally, endophytic fungi have been shown to mitigate salinity effects through symbiosis with plants. This study evaluated three endophytic fungi isolated from Lavandula stoechas L. in the grasslands of Extremadura (i.e., Diplodia corticola L11, Leptobacillium leptobactrum L15, and Cladosporium cladosporioides L16) for their ability to improve hydroponic forage production under saline conditions. In vitro experiments were conducted assessing plant growth promotion and fungal growth under salinity, followed by research evaluating the impact of fungal inoculation on hydroponic wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) forages irrigated with NaCl solutions (0, 100, and 200 mM). The results showed improved fungal growth and production of plant growth-promoting substances, which could explain the improved plant germination, shoot and root length, fresh and dry weight, and yield of inoculated plants growing under salinity. Plants inoculated with L15 or L16 showed the best performance overall. L15 demonstrated broader bioactivity in vitro, potentially explaining its superior performance in both wheat and barley growth. Conversely, L16 was more effective in barley, while L11 was beneficial in wheat but detrimental in barley. This study provides a preliminary exploration of the capabilities of these fungi and their optimization for hydroponic forage production.

The pivotal role of arbuscular mycorrhizal fungi in enhancing plant biomass and nutrient availability under drought stress conditions: A global meta-analysis

Drought is a serious threat to crop productivity and global food security. About 40 % of the worldwide land is considered arid dryland soil because of a lack of rainfall, high solar radiation, and temperature fluctuations. Though rhizobacteria, particularly mycorrhizal fungi (MF), assist plants in coping with drought stress, an intensive quantitative assessment of their effects on plant growth and nutrient availability is still limited. We systematically carried out a global meta-analysis using 122 peer-reviewed publications comprising 3534 observations to investigate the effects of MF on plant biomass (PB) and nutrient availability (nitrogen: N and phosphorus: P) under drought-stress conditions. The results show that the MF inoculation significantly increased mycorrhizal colonization (MC), N and P uptakes, and plant biomass (PB) at a C:N ratio > 15 by 2171.44 %, 23.74 %, 135.61 %, and 220.91 %, respectively. The MF species Claroideoglomus etunicatum and Glomus significantly influenced the MC, N, and PB concentrations by 2541.68 %, 40.35 %, and 110.85 %, respectively. Moreover, the concentrations of MC, N, and PB were considerably affected by the soil texture categories, with the maximum levels of 4940.04 %, 127.05 %, and 84.04 % found in sandy, clay, and clay loam soils, respectively. In addition, soil pH, crop types, soil textural class, and MF species were identified as vital pedologic factors affecting plant growth and nutrient availability during fungal inoculation. Overall, this meta-analysis addresses gaps in understanding the effects of MF inoculation on plant development and nutrient availability under drought stress.

Unveiling the hidden world: How arbuscular mycorrhizal fungi and its regulated core fungi modify the composition and metabolism of soybean rhizosphere microbiome

BackgroundThe symbiosis between arbuscular mycorrhizal fungi (AMF) and plants often stimulates plant growth, increases agricultural yield, reduces costs, thereby providing significant economic benefits. AMF can also benefit plants through affecting the rhizosphere microbial community, but the underlying mechanisms remain unclear. Using Rhizophagus intraradices as a model AMF species, we assessed how AMF influences the bacterial composition and functional diversity through 16 S rRNA gene sequencing and non-targeted metabolomics analysis in the rhizosphere of aluminum-sensitive soybean that were inoculated with pathogenic fungus Nigrospora oryzae and phosphorus-solubilizing fungus Talaromyces verruculosus in an acidic soil.ResultsThe inoculation of R. intraradices, N. oryzae and T. verruculosus didn’t have a significant influence on the levels of soil C, N, and P, or various plant characteristics such as seed weight, crude fat and protein content. However, their inoculation affected the structure, function and nutrient dynamics of the resident bacterial community. The co-inoculation of T. verruculosus and R. intraradices increased the relative abundance of Pseudomonas psychrotolerans, which was capable of N-fixing and was related to cry-for-help theory (plants signal for beneficial microbes when under stress), within the rhizosphere. R. intraradices increased the expression of metabolic pathways associated with the synthesis of unsaturated fatty acids, which was known to enhance plant resistance under adverse environmental conditions. The inoculation of N. oryzae stimulated the stress response inside the soil environment by enriching the polyene macrolide antifungal antibiotic-producing bacterial genus Streptomyces in the root endosphere and upregulating two antibacterial activity metabolic pathways associated with steroid biosynthesis pathways in the rhizosphere. Although inoculation of pathogenic fungus N. oryzae enriched Bradyrhizobium and increased soil urease activity, it had no significant effects on biomass and N content of soybean. Lastly, the host niches exhibited differences in the composition of the bacterial community, with most N-fixing bacteria accumulating in the endosphere and Rhizobium vallis only detected in the endosphere.ConclusionsOur findings demonstrate that intricate interactions between AMF, associated core fungi, and the soybean root-associated ecological niches co-mediate the regulation of soybean growth, the dynamics of rhizosphere soil nutrients, and the composition, function, and metabolisms of the root-associated microbiome in an acidic soil.

Enhancing Iron and Zinc Uptake in Spring Wheat Through Commercial Arbuscular Mycorrhizal Fungi Inoculation under Different Soil Phosphorus Addition Levels

Improving the concentrations and bioavailability of micronutrients, especially iron (Fe) and zinc (Zn), in crop grains is important to alleviate their deficiencies in humans. Inoculating crops with arbuscular mycorrhizal fungi (AMF) can potentially enhance soil nutrient supply and crop yield, but the effectiveness is influenced by soil factors, particularly soil phosphorus (P) availability. A greenhouse pot experiment was conducted to evaluate the effect of a commercial AMF product on spring wheat (Triticum aestivum L.) yield and grain concentrations of Zn and Fe under different soil P addition levels (0, 5 and 20 mg P kg-1 dry soil). Results showed that AMF inoculation significantly increased root colonization rate of wheat across all P addition levels. Wheat growth, as evidenced by dry weights of shoot and grain, was significantly enhanced by AMF and high P addition treatments. AMF inoculation did not affect grain Zn concentration, but significantly increased grain Fe concentration compared to the un-inoculated control. As expected, P addition resulted in a significant reduction in grain concentrations of Fe and Zn, primarily due to a growth dilution effect. An integrated analysis using the radar plot concludes that AMF inoculation is most effective in increasing crop yield and grain micronutrient concentrations when soil P levels are low. Importantly, while adequate P supply is crucial for maintaining crop productivity, it may decrease grain micronutrient availability without complementary strategies.

Mycorrhizal Fungal Inoculum Potential in Crop Rotation Soil With Different Levels of Irrigation

Research indicates arbuscular mycorrhizal fungi (AMF) inoculum potential and AMF biomass production in agricultural soil are strongly influenced by both soil moisture availability and crop rotation (CR) strategies. We hypothesized that AMF biomass production in and inoculum potential of Wyoming semiarid agricultural soil would increase when managed using CR and irrigation. To test this hypothesis, we examined AMF activity (AMF biomarker fatty acid, and AMF infection of roots) in two differently managed soils (no-CR soil and two-year CR soil) in a field experiment. Furthermore, in a greenhouse experiment, we examined AMF activity in the same two CR treatment soils under different irrigation regimes (wet, irrigated to 60% field capacity, and dry, irrigated to 15% field capacity). Notably, the two-year CR soil had greater amounts of AMF biomarker fatty acid and greater inoculum potential, and higher percentage of AMF root colonization compared to no-CR soil. Despite the fact that the CR soil had more AMF propagules, it was less than the undisturbed non-agricultural native sage-grassland soils previously reported. Overall, the findings suggest that high levels of irrigation can inhibit the activity of AMF adapted to semiarid soil conditions and CR can increase activity of AMF in soils from semiarid regions.

Improving Inoculum Production of Arbuscular Mycorrhizal Fungi in Zea mays L. Using Light-Emitting Diode (LED) Technology

A substrate-based production system is a simple and low-cost method for arbuscular mycorrhizal (AM) fungal inoculum production. However, it is time-consuming and typically yields low numbers of AM fungal spores due to several factors affecting plant growth efficiency. Our study investigated the use of light-emitting diode (LED) technology to expedite AM fungal spore production in planta. We performed experiments with Rhizophagus irregularis inoculated in maize (Zea mays L.), contrasting LED light with greenhouse (GH) conditions. Our results exhibited a significant improvement in AM fungal colonization and spore production, as well as a reduction in the production period from 120 to 90 days under the LED light condition. This was achieved using a red-and-blue light ratio of 60:40 with a total light intensity of 300 µmol m−2 s−1. The LED light treatments improved maize growth by increasing nitrogen (N) and phosphorus (P) concentrations in shoots and roots, respectively. Our gene expression analyses revealed that in AMF-inoculated plants, genes related to photosynthesis were significantly upregulated under LED light compared to the GH condition. Moreover, LED increased the expression of marker genes linked to the AM fungi-related cell cycle, indicating enhanced AM fungal growth during symbiosis. These findings advance our comprehension of LED applications in agriculture, offering promising prospects for acceleration of AM fungal spore production.

Arbuscular mycorrhizal fungal inoculum and N2-fixing plants in ecological reclamation of arid mining areas: nutrient limitation of the moss biocrust microbiome.

Ecoenzymatic stoichiometry can reflect the ability of soil microorganisms to acquire energy and nutrients and to determine their response to environmental stresses. However, the drivers of metabolic limitation of the moss biocrust microbiome during the ecological restoration of coal mining areas are poorly understood. Therefore, in this study, enzymatic stoichiometry modeling and high-throughput sequencing were used to simultaneously determine moss biocrust microbial metabolic limitation and its relationship with moss biocrust nutrients and arbuscular mycorrhizal fungal (AMF) diversity in five arid and semi-arid revegetation types (Hippophae rhamnoides, Amorpha fruticosa, Cerasus humilis, Cerasus szechuanica, and Xanthoceras sorbifolium) and two microbial treatments (AMF-inoculated and uninoculated). The activities of moss biocrust carbon (C)-, nitrogen (N)-, and phosphorus (P)-acquiring enzymes and organic carbon fractions in the AMF-inoculated treatment were significantly higher than those in the uninoculated control. Moss biocrust microbial community C and P limitations were observed in the five revegetation types, with lower limitation in general in the AMF-inoculated treatment. Dinitrogen-fixing plants (Amorpha fruticosa and Hippophae rhamnoides) significantly mitigated moss biocrust microbiome C and P limitation, especially in the AMF-inoculated treatment. Furthermore, partial least squares path modeling (PLS-PM) shows that moss biocrust organic carbon fractions (- 0.73 and - 0.81 of the total effects, respectively) and AMF diversity (- 0.73 and - 0.81 of the total effects) had negative effect on microbial C and P limitation, suggesting that more efficient active nutrients and AMF diversity are important factors alleviating limitation of moss biocrust microbial metabolism. This indicates that moss biocrust microbial communities under N2-fixing species with AMF inoculation were more stable under environmental stress; thus, AMF inoculation and/or N2-fixing plants may be recommended as preferred options for the ecological restoration of arid mining areas.

Physiological acclimatization in a medium amended with colloidal chitin improves the nematophagous capacity of a fungus on the tomato root-knot nematode

Purpureocillium lilacinum is a nematophagous fungus whose ability to control the plant parasitic nematode Nacobbus aberrans sensu lato has been demonstrated. In this study, physiological acclimatization was performed using different nutrient sources and water activity levels of the culture medium to improve the nematophagous activity of two strains of P. lilacinum (SR14 and SR38). The development of the fungal inoculum in a medium amended with colloidal chitin and reduced levels of water activity (0.95) stimulates the production of conidia and pathogenicity in vitro. This condition was selected to produce the fungal inoculum for conducting antagonism studies against N. aberrans s.l. in tomato plants. The nematode population was significantly reduced (94–96%) with the application of SR38 and SR14 + SR38. The physiological acclimatization in medium with colloidal chitin and 0.95 water activity stimulates the pathogenicity mechanisms (sporulation and infectivity) of P. lilacinum SR38, improving its nematophagous capacity.

Optimizing mycorrhizal fungi application for improved nutrient uptake, growth, and disease resistance in cardamom seedlings (Elettaria cardamomum (L.) Maton)

This study evaluated the impact of various doses (5, 10, 15 g) and application sequences (1, 2, or 3 times at monthly intervals) of arbuscular mycorrhizal (AM) fungal inoculum on cardamom seedlings over two years (2020–2021 and 2021–2022). The results indicated that the dosage of AM inoculum had a more substantial effect on the seedlings than the application sequence. A 10 g dose significantly increased shoot length and dry weight, while three applications of 5 g each improved the number of fibrous roots. Although potassium uptake was not affected, phosphorus and calcium uptake were highest with the 10 g dose. Arbuscular mycorrhizal inoculation also enhanced phosphatase activity in the rhizosphere, with 5 g improving acid phosphatase and 10 g improving alkaline phosphatase activity. Disease incidence, including seedling rot was lower with the 10 g dose, and additional sequential applications did not further reduce disease. Structural equation modeling (SEM) revealed that AM colonization positively influenced dry weight through the number of fibrous roots, showing a strong relationship between AM dose, colonization, spore count, and mycorrhizal dependency. This study indicates that applying a 10 g dose of AM fungal inoculum can be particularly beneficial in agroecosystems for improving cardamom seedling growth, nutrient uptake, and disease resistance.

Influence of endophytic fungi treatments on aluminum contents in Vernicia montana seedlings and soils under different concentrations of aluminum stress

Although leveraging the interaction with endophytic fungi is an efficient and environment-friendly strategy for plants to enhance growth and resistance, how different endophyte species influence host plants’ resilience in adverse conditions remain comparatively unclear. In order to explore the effect of endophytic fungi on the aluminum resistance of woody host plants, Vernicia montana seedlings were subjected to different aluminum concentrations (T0, T1, T2, T3, T4) in this study. The aluminum contents in roots, leaves and rhizospheric soil of V. montana seedlings were determined after applying endophyte suspensions of Pestalotiopsis (NP), Alternaria (LA), Penicillium (QP), Coniothyrium (DC) and Thermophilic (ST) spp. The results showed that aluminum stress treatment, endophytic fungi treatment and their interaction had significant effects on aluminum content in leaves, aluminum content in roots, aluminum content in rhizospheric soil, and the transport and retention rate of aluminum ions in soil-root-leaf. With the increase of aluminum concentrations, the aluminum content in leaves of V. montana increased in the endophyte treatments of LA and ST, decreased in CK, NP and DC, or had marginal variation in QP treatment. Compared with T0, four endophyte treatments of LA, QP, DC and ST significantly reduced root aluminum content under T4 concentration (P < 0.05), contrary to the results of NP treatment. Endophyte treatments significantly increased root aluminum content of V. montana under T1 concentration (P < 0.05). The foliar Al content in fungi-inoculated seedlings was significantly lower than that of the non-inoculated ones under T0 and T3 levels (P < 0.05), the LRR is less than 1, while the opposite trend was observed under T2 and T4 treatments. The aluminum transport coefficient TFsoil-root and TFroot-leaf increased in different proportions under the same aluminum concentration. The findings indicate that the application of endophytic fungi change the aluminum contents and transport from rhizospheric soil, roots to leaves. The specific effects of endophytic fungi vary with the degree of aluminum stress and the fungi genus. The study proves that inoculation of endophytic fungi can improve the aluminum tolerance of host plants, and thereby play an important role in promoting the sustainable development of forestry.

Response of wheat to arbuscular mycorrhizal fungi inoculation and biochar application: Implications for soil carbon sequestration

The sequestration of atmospheric CO₂ in soil is suggested as an effective climate change mitigation strategy. Biochar application shows promise in this regard, while the role of fungi in soil carbon cycling and sequestration is also under investigation. Using a novel high-throughput plant phenomics approach, we explore the impact of arbuscular mycorrhizal fungi (AMF) inoculation and biochar application on wheat growth and soil carbon, guided by one of the leading global carbon credit schemes. Wheat was successfully colonised by AMF, achieving an average root length colonisation of 35.9%. We uncover an indirect fungal-mediated pathway to soil carbon sequestration, with mycorrhizal plants generating more biomass across all soil treatments without yield penalties, suggesting colonised plants deliver more plant derived carbon to the soil, potentially leading to long-term soil carbon gains. Conversely, fungal-driven carbon loss occurred, significantly reducing soil carbon accumulation in unamended soil, but not in biochar-amended soil, suggesting that biochar moderates fungal activity and positively impacts the soil carbon balance. While both biochar and AMF enhance plant growth, their direct effects on soil carbon are complex. Although biochar did not significantly increase soil carbon stocks beyond its own contribution, its ability to regulate fungal activity could play an important role in influencing soil carbon sequestration.

Arbuscular mycorrhizal fungi affected soft wheat quality properties and nutritional index by regulating the composition and secondary structure of protein

Arbuscular mycorrhizal fungi (AMF) inoculation has important regulatory influence on plant growth and nitrogen uptake, which are intimately associated with soft wheat yield and quality. The study aimed to investigate the impact of AMF inoculation on soft wheat grain yield, protein compositions, protein quality, secondary structure of gluten, dough properties and biscuits baking quality. In this study, AMF inoculation significantly increased grain yield. AMF inoculation decreased grain protein content by 5.1%, glutenin content by 8.5%, GMP by 14.3%, and HMW-GS by 8.8% compared with CK. Conversely, AMF inoculation increased the ratio of gliadin/glutenin. Further analysis showed AMF treatment had a looser gluten network than CK, significantly reduced β-sheet and β-turn content, while α-helix content increased. The nutritional index of grain protein was slightly reduced under AMF inoculation, yet the biological value was improved. Reduced wet gluten content, gluten performance index and dough development time under AMF treatment through regulation of soft wheat protein composition and gluten protein structure. Therefore, biscuits in AMF treatment showed reduced thickness, hardness, significantly greater spread ratio and sensory score compared with CK. These indicate that AMF application would be a beneficial agronomic practice to synergistically optimize yield and grain quality in soft wheat.

Effect of mutations in the &lt;i&gt;Sym7&lt;/i&gt;, &lt;i&gt;Sym19&lt;/i&gt; and &lt;i&gt;Sym34&lt;/i&gt; genes on the interaction of pea (&lt;i&gt;Pisum sativum&lt;/i&gt; L.) with the arbuscular mycorrhizal fungus &lt;i&gt;Rhizophagus irregularis&lt;/i&gt;

BACKGROUND: Within the pea (Pisum sativum L.) species, genotypes with high and low responsiveness to inoculation with arbuscular mycorrhizal fungi can be distinguished. AIM: The aim of this study was to test the hypothesis that pea responsiveness to arbuscular mycorrhizal fungi inoculation may be inversely correlated with root colonization levels. MATERIALS AND METHODS: The wild-type line Finale with low responsiveness to arbuscular mycorrhizal fungi inoculation and symbiotic mutants obtained on its basis were used. Plants were grown under controlled climatic conditions with a deficiency of available phosphorus; the fungus Rhizophagus irregularis was used for inoculation. Parameters of plant growth and development of reproductive organs were determined 52 and 71 days after inoculation, which corresponded to the flowering and pod filling stages, respectively. RESULTS: All mutant lines under conditions without inoculation had generally reduced parameters compared to the original line Finale. Inoculation led to a decrease in many parameters in the line Finale. Mutations in the Sym7 and Sym34 genes, which led to a decrease or delay in the start of mycorrhization, respectively, contributed to the manifestation of a positive plant response to inoculation. The mutant in the Sym19 gene almost completely lacked intrartadical colonization, while inoculation had no effect on the growth and development of above-ground organs. CONCLUSIONS: The study results support the idea that reducing mycorrhization levels can have a positive effect on pea plants.

Spray inoculation and image analysis-based quantification of powdery mildew disease severity on pea leaves

Pea (Pisum sativum) is an important agricultural legume crop, but powdery mildew disease caused by the biotrophic fungus Erysiphe pisi regularly limits its annual yield. Assays to evaluate the efficacy of potential antifungal compounds or resistance genes for disease control require a simple fungal inoculation method that provides control over the initial inoculum concentration and enables uniform inoculum distribution within a leaf and across replicates as well as a method for the quantitative assessment of disease severity. Here, we present an easy spray inoculation method for the uniform distribution of a defined concentration of E. pisi conidia on the leaves of pea plants and a semi-automated image analysis-based quantification of disease symptoms. The uniformity in conidial distribution was validated using a novel grading system termed the uniformity index. In addition, RT-qPCR was used to validate the reproducibility of the spray inoculation method and image analysis-based disease quantification. These procedures permit the accurate quantification of powdery mildew disease severity at macroscopic and molecular levels.•Uniform and reproducible inoculum distribution on leaves using a simple and inexpensive spray device•Rapid and reproducible quantification of powdery mildew disease symptoms using open-source software without the requirement of computational expertise

Enhanced fig tree production through endomycorrhizal fungi inoculation: A nursery study on tree cuttings derived from the Ifrane Region, Morocco

The mycorrhizal association represents a crucial symbiotic bond necessary for the vitality of the majority of plants. This report aims to investigate the impact of endomycorrhizal fungi on the production of fig trees from cuttings. The research took place in a nursery environment by inoculating fig cuttings sourced from three sites in Morocco with a composite inoculum of arbuscular mycorrhizal fungi (AMF). The mean root and vegetative masses of the inoculated plants after 140 days were 33.1 g and 35 g compared with 1.8 g and 6.4 g in the control. The mean shoot length and number of leaves developed from treated cutting were 98.5 cm and 17, respectively 29 cm and 4 leaves in control. Thus, the newly formed roots showed a well-established mycorrhizal colonization and contained different structures characteristic of arbuscular endomycorrhizae: arbuscules, vesicles, endophytes, hyphae and spores. The frequency and intensity of root mycorrhization were approximately 80% and 15.5%, respectively. The contents of arbuscules and vesicles were 2.5% and 5.5%. The study of formed spores showed a combination of 52 spores per 100 g of soil, belonging to 11 species and 3 genera: Glomus, Acaulospora and Rhizophagus with dominance of the genus Glomus (85%). Glomus macrocarpum and Glomus deserticola were the most abundant species, appearing at 30.77% and 19.23%, respectively. The results demonstrate a pronounced stimulating effect on both root formation and vegetative shoot development in the inoculated cuttings. Specifically, the early inoculation of fig cutting with the AMF inoculum significantly enhanced rhizogenesis end root system development. Consequently, the gradual establishment of mycorrhizal symbiosis at the root level of inoculated plants led to good development of the root mass and the vegetative mass. The inoculated plants showed good root and vegetative mass development due to the installation and the progressive development of mycorrhizal symbiosis at their roots.

Rhizofungus Aspergillus terreus Mitigates Heavy Metal Stress-Associated Damage in Triticum aestivum L.

Industrial waste and sewage deposit heavy metals into the soil, where they can remain for long periods. Although there are several methods to manage heavy metals in agricultural soil, microorganisms present a promising and effective solution for their detoxification. We isolated a rhizofungus, Aspergillus terreus (GenBank Acc. No. KT310979.1), from Parthenium hysterophorus L., and investigated its growth-promoting and metal detoxification capabilities. The isolated fungus was evaluated for its ability to mitigate lead (25 and 75 ppm) and copper (100 and 200 ppm) toxicity in Triticum aestivum L. seedlings. The experiment utilized a completely randomized design with three replicates for each treatment. A. terreus successfully colonized the roots of wheat seedlings, even in the presence of heavy metals, and significantly enhanced plant growth. The isolate effectively alleviates lead and copper stress in wheat seedlings, as evidenced by increases in shoot length (142%), root length (98%), fresh weight (24%), dry weight (73%), protein content (31%), and sugar content (40%). It was observed that wheat seedlings possess a basic defense system against stress, but it was insufficient to support normal growth. Fungal inoculation strengthened the host's defense system and reduced its exposure to toxic heavy metals. In treated seedlings, exposure to heavy metals significantly upregulated MT1 gene expression, which aided in metal detoxification, enhanced antioxidant defenses, and maintained metal homeostasis. A reduction in metal exposure was observed in several areas, including normalizing the activities of antioxidant enzymes that had been elevated by up to 67% following exposure to Pb (75 mg/kg) and Cu (200 mg/kg). Heavy metal exposure elevated antioxidant levels but also increased ROS levels by 86%. However, with Aspergillus terreus colonization, ROS levels stayed within normal ranges. This decrease in ROS was associated with reduced malondialdehyde (MDA) levels, enhanced membrane stability, and restored root architecture. In conclusion, rhizofungal colonization improved metal tolerance in seedlings by decreasing metal uptake and increasing the levels of metal-binding metallothionein proteins.

Solubilization and enhanced degradation of benzene phenolic derivatives-Bisphenol A/Triclosan using a biosurfactant producing white rot fungus Hypocrea lixii S5 with plant growth promoting traits.

Endocrine disrupting chemicals (EDCs) as benzene phenolic derivatives being hydrophobic partition to organic matter in sludge/soil sediments and show slow degradation rate owing to poor bioavailability to microbes. In the present study, the potential of a versatile white rot fungal isolate S5 identified as Hypocrea lixii was monitored to degrade bisphenol A (BPA)/triclosan (TCS) under shake flask conditions with concomitant production of lipopeptide biosurfactant (BS) and plant growth promotion. Sufficient growth of WRF for 5 days before supplementation of 50 ppm EDC (BPA/TCS) in set B showed an increase in degradation rates by 23% and 29% with corresponding increase in secretion of lignin-modifying enzymes compared to set A wherein almost 84% and 97% inhibition in fungal growth was observed when BPA/TCS were added at time of fungal inoculation. Further in set B, EDC concentration stimulated expression of laccase and lignin peroxidase (Lip) with 24.44 U/L of laccase and 281.69 U/L of Lip in 100 ppm BPA and 344 U/L Lip in 50 ppm TCS supplemented medium compared to their respective controls (without EDC). Biodegradation was also found to be correlated with lowering of surface tension from 57.02 mN/m (uninoculated control) to 44.16 mN/m in case of BPA and 38.49 mN/m in TCS, indicative of biosurfactant (BS) production. FTIR, GC-MS, and LC-ESI/MSMS confirmed the presence of surfactin lipopeptide isoforms. The WRF also displayed positive plant growth promoting traits as production of ammonia, indole acetic acid, siderophores, Zn solubilization, and 1-1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, reflecting its soil restoration ability. The combined traits of biosurfactant production, EDC degradation and plant growth promotion displayed by WRF will help in emulsifying the hydrophobic pollutants favoring their fast degradation along with restoration of contaminated soil in natural conditions.

Bioinoculation Strategies for Enhanced Growth and Development of Economically Important Dalbergia latifolia Roxb

The present experiment was conducted to evaluate the plant growth properties of the native rhizospheric microflora of Dalbergia latifolia, an important medicinal, timber and biofuel plant. A systemic isolation, characterization and identification of rhizospheric soil, collected indigenously, initially produced 45 numbers of fungi and 3 numbers of bacteria. Both groups of organisms were characterized for their extracellular useful activity, especially phosphate solubilisation potential, and presented in terms of solubilisation index and solubilisation efficiency. Two fungi and two bacteria with good phosphate solubilization activity, along with NPK and organic manure, were selected and used in a pot culture experiment to promote the growth and development of Dalbergia latifolia under nursery conditions. Data recorded on 90 Days of plant growth exhibited the growth promotion of inoculated plants over control uninoculated experimental set. Results obtained on morphological and physiological growth parameters exhibited that the application of Aspergillus flavus followed by Burkholderia territorii + org. manure showed maximum shoot height and inoculation of Burkholderia anthina + Aspergillus sp. + NPK was significantly higher leaf area. Significantly longer root has been observed in Burkholderia territorii. However, a difference was observed in the number of leaves in Aspergillus flavus. + Org. manure and higher numbers of branches were observed in Aspergillus flavus only as compared to uninoculated control. Coinoculation of Aspergillus flavus + Penicillium simplicissimum showed better performance in fresh and dry shoot biomass as compared to other treatments. Burkholderia territorii + Org.manure produced higher fresh biomass of roots and coinoculation of bacteria Burkholderia territorii + Burkholderia anthina helped in enhancing root dry biomass. Dual inoculation of Aspergillus flavus + Penicillium simplicissimum gives better result in both fresh biomass of leaves and dry biomass of leaves. Application of Aspergillus flavus + Penicillium simplicissimum enhanced the total fresh biomass of the seedlings whereas supplementation of Burkholderia anthina + Penicillium simplicissimum enhanced the total dry biomass. Coinoculation of Aspergillus flavus + Penicillium simplicissimum showed higher RGR and coinoculation of Burkholderia anthina + Aspergillus flavus + NPK showed quite higher Leaf area ratio (LAR cm2gm-1). Co inoculation of Burkholderia territorii + Burkholderia anthina + Organic Manure showed highest root-shoot ratio and Coinoculation of Penicillium simplicissimum + Org. manure showed higher Net assimilation rate (NAR). However, Bacterial and fungal inoculants were also used as potent bioinoculants for the growth and establishment of crops of forest tree species.

Effect of humic acids extracted from different organic sources and inoculation with Bacillus subtilis or Aspergillus Niger on urease activity in calcareous soil

Humic substances have received a large share of research and development as amendments to poor fertility soils that are poor in fertility and have deteriorating physical properties, since the process of extracting is a common process and easy to implement, as well as diluting these acids with water enables them to be used at economically acceptable levels over large areas. It is necessary to noticed that the properties of these acids depending on the organic source and the concentration added to the soil. A laboratory experiment was conducted at the Department of Soil Sciences and Water Resources, College of Agriculture, University of Basrah ,IRAQ to demonstrate the effect of humic substances extracted from different sources and inoculation with Bacillus subtilis or Aspergillus niger on the activity of the urease in calcareous soil. Wheat straw, alfalfa leaves, goat waste and poultry waste were composted aerobically for 3 months by filling a hole of 2×2×1.5 m by layers of such waste ,turned weekly for aeration. Each pile was extracted for humic acids (humic acid + fulvic acid) . Humic acid mixed with to soil at levels of 0, 25, and 50 L h-1. The soil was also inoculated with Bacillus subtilis or Aspergillus niger isolated from local soil at rates of 20.06×106 and 40× 103 cfu ml-1, respectively The samples were incubated at field capacity level 28±2°C for 30 days. Urease activity was estimated after 7 or 30 days by determining NH4+ released using steam distillation method . A decrease in urease activity was observed when treated with different types of humic acid compared to the control treatment. The lowest activity was obtained at humic acids extracted from poultry waste, reaching 312.0 and 188.72 µg N-NH4+g-1soil.2h-1 at incubation periods of 7 and 30 days, respectively .The results also indicated that increasing the level of humic acids significantly inhibited the activity of the enzyme. However, in soil treated with Bacillus subtilis or Aspergillus niger, an increase in urease activity was observed compared to the non-inoculation treatment. Treatment with the fungal inoculant had higher activity than the bacterial inoculum, reaching 324.5 and 297.2 µg N-NH4+ g-1 soil 2 hours-1 for both inoculants at a period of 7 days, and 178.09 and 150.31 µg N-NH4+g-1soil.2h-1at a period of 30 days, respectively.It is proposed that the inhibition of urease by humic acid addition may benefit for increasing urea fertilizer efficiency.

Zinc finger protein LjRSDL regulates arbuscule degeneration of arbuscular mycorrhizal fungi in Lotus japonicus.

In arbuscular mycorrhizal (AM) symbiosis, appropriate regulation of the formation, maintenance, and degeneration of the arbuscule are essential for plants and fungi. In this study, we identified a Cysteine-2/Histidine-2 zinc finger protein (C2H2-ZFP)-encoding gene in Lotus japonicus named Regulator of Symbiosome Differentiation-Like (LjRSDL) that is required for arbuscule degeneration. Evolutionary analysis showed that homologs of LjRSDL exist in mycorrhizal flowering plants. We obtained ProLjRSDL::GUS transgenic hairy roots and showed that LjRSDL was strongly upregulated upon AM colonization, particularly at 18 days post AM fungi inoculation and specifically expressed in arbuscular-containing cells. The mycorrhization rate increased in the ljrsdl mutant but decreased in LjRSDL overexpressed L. japonicus. Interestingly, we observed higher proportions of large arbuscule in the ljrsdl mutant but lower proportions of larger arbuscule in LjRSDL overexpressing plants. Transcriptome analyses indicated that genes involved in arbuscule degeneration were significantly changed upon the dysregulation of LjRSDL and that LjRSDL-dependent regulation in AM symbiosis is mainly via the hormone signal transduction pathway. LjRSDL, therefore, represents a C2H2-ZFP that negatively regulates AM symbiosis. Our study provides insight into understanding plant-AM fungal communication and AM symbiosis development.