Investigation on mycelial growth requirements of Cantharellus cibarius under laboratory conditions

Evaluating the effectiveness of Pisolithus tinctorius in enhancing the Eucalyptus' resistance to salt stress

Afforestation projects on saline land, using Eucalyptus trees and ectomycorrhizal fungi, are crucial for restoring affected areas and promoting ecological and economic benefits, particularly in saline-affected areas. This study was conducted to isolate Pisolithus sp. and estimate its potential to improve the growth performance of Eucalyptus globulus seedlings under salt-stress conditions. Pisolithus sp. was isolated from mature sporocarps and identified through 18S rDNA. Pisolithus sp. was evaluated for its response to varying pH values, temperatures, and salinity levels. A pot experiment was conducted to assess the Pisolithus strain's effectiveness in reducing soil salinity's impact on the growth of Eucalyptus globulus seedlings in sandy soil. The identified Pisolithus tinctorius with an accession number of OM125275 revealed the highest mycelium dry weight of 0.09 g/100 ml medium at pH 5.8, 0.08 g/100 ml medium at 28 °C, and 0.12 g/100 ml medium at 4% NaCl. Eucalyptus globulus seedlings inoculated with Pisolithus tinctorius demonstrated significant improvement in most parameters compared to non-mycorrhizal (control) seedlings under salt stress. The seedlings inoculated with Pisolithus tinctorius and irrigated with 6 dS/m saline water revealed the highest shoot height (55.670 cm), root length (42.33 cm), shoot fresh weight (6.44 g/plant), root fresh weight (1.84 g/plant), shoot dry weight (2.37 g/plant), and root dry weight (0.810 g/plant) when compared to all treatments. Our findings suggest that selecting appropriate fungal strains is crucial for improving plant performance in saline conditions.

Effect of Culture Media on the Yield and Protein Content of Pleurotus ostreatus (Jacq.) Kumm Mycelia

The development of alternative proteins derived from fungi-based sources is gaining recognition due to their health benefits and lower environmental impact, compared to traditional animal-based sources. In this study, we investigated the culture conditions for Pleurotus ostreatus mycelia, focusing on the nutritional requirements and yield optimization using solid surface culture and liquid-state culture methods. Our findings indicate that optimal culture conditions involve glucose as the primary carbon source, with an initial pH of 6.0. By the eighth day of the culture period, media formulated with amaranth seed flour and Bambara groundnut flour yielded the highest mycelial protein content, characterized by a compact filamentous network with fewer open pores. Additionally, urea supplementation at 0.01% concentration on amaranth seed-based nutrient medium significantly increased the protein content from 31.4% to 38.7% (dry weight basis). The research findings contribute to the development of fungal-based proteins, which are essential in the production of sustainable food products.

Optimizing conditions of mycelial inoculum immobilized in Ca-alginate beads: a case study in ectomycorrhizal fungus Astraeus odoratus

Ectomycorrhizal inoculum has emerged as a critical tool for forest restoration, especially under challenging climate change conditions. The inoculation of selective ectomycorrhizal fungi can enhance seedling survival and subsequent growth in the field. This study optimized the liquid media for mycelial growth of Astraeus odoratus strain K1 and the sodium alginate solution composition for enhanced mycelial viability after entrapment. Using Modified Melin-Norkrans as the optimal media for mycelial cultivation and 2% sodium alginate supplemented with Czapek medium, 0.25% activated charcoal, 5% sucrose, and 5% sorbitol in the alginate solution yielded the highest viability of A. odoratus mycelia. Preservation in distilled water and 10% glycerol at 25 °C for 60 days proved to be the most effective storage condition for the alginate beads. Both fresh and preserved alginate beads were tested for colonizing on Hopea odorata Roxb. seedlings, showing successful colonization and ectomycorrhizal root formation, with over 49% colonization. This study fills a crucial gap in biotechnology and ectomycorrhizal inoculum, paving the way for more effective and sustainable forest restoration practices.

Bioremediation of hazardous heavy metals by marine microorganisms: a recent review

Heavy metals (HMs) like Zn, Cu, Pb, Ni, Cd, and Hg, among others, play a role in several environmental problems. The marine environment is polluted by several contaminants, such as HMs. A variety of physico-chemical methods usually available for sanitation HMs remediation suffer from either limitation. Bioremediation is a promising way of dealing with HMs pollution. Microbes have the ability with various potencies to resist HMs tension. The current review discusses the main sources and influences of HMs, the role of marine microorganisms in HMs bioremediation, as well as the microbial mechanisms for HMs detoxification and transformation. This review paper aims to provide an overview of the bioremediation technologies that are currently available for the removal of HMs ions from industrial and urban effluent by aquatic organisms such as bacteria, fungi, and microalgae, particularly those that are isolated from marine areas. The primary goals are to outline various studies and offer helpful information about the most important aspects of the bioelimination techniques. The biotreatment practices have been primarily divided into three techniques based on this topic. They are biosorption, bioaccumulation, bioleaching, and biotransformation. This article gives the brief view on the research studies about bioremediation of HMs using marine microorganisms. The current review also deals with the critical issues and recent studies based on the HMs biodetoxification using aquatic microorganisms.

Promotion of Plant Growth in Arid Zones by Selected Trichoderma spp. Strains with Adaptation Plasticity to Alkaline pH

Trichoderma species are filamentous fungi that support plant health and confer improved growth, disease resistance, and abiotic stress tolerance. The objective of this study is to describe the physiological characteristics of the abundance and structure of Trichoderma model strains from arid zones and evaluate and describe their possible adaptation and modulation in alkaline pH. The presence of biotic factors such as phytopathogens forces farmers to take more actions such as using pesticides. In addition, factors such as the lack of water worldwide lead to losses in agricultural production. Therefore, the search for biocontrol microorganisms that support drought opens the door to the search for variations in the molecular mechanisms involved in these phenomena. In our case, we isolated 11 tested Trichoderma fungal strains from samples collected both from the rhizosphere and roots from two endemic plants. We probed their molecular markers to obtain their identity and assessed their resistance to alkaline conditions, as well as their response to mycoparasitism, plant growth promotion, and drought stress. The findings were worthy of being analyzed in depth. Three fungal taxa/species were grouped by phylogenetic/phenotypic characteristics; three T. harzianum strains showed outstanding capabilities to adapt to alkalinity stress. They also showed antagonistic activity against three phytopathogenic fungi. Additionally, we provided evidence of significant growth promotion in Sorghum bicolor seedlings under endemic agriculture conditions and a reduction in drought damage with Trichoderma infection. Finally, beneficial fungi adapted to specific ambient niches use various molecular mechanisms to survive and modulate their metabolism.

Mushrooms as Potential Sources of Active Metabolites and Medicines

Background

Mushrooms exist as an integral and vital component of the ecosystem and are very precious fungi. Mushrooms have been traditionally used in herbal medicines for many centuries.

Scope and Approach

There are a variety of medicinal mushrooms mentioned in the current work such as Agaricus, Amanita, Calocybe, Cantharellus, Cordyceps, Coprinus, Cortinarius, Ganoderma, Grifola, Huitlacoche, Hydnum, Lentinus, Morchella, Pleurotus, Rigidoporus, Tremella, Trametes sp., etc., which play a vital role in various diseases because of several metabolic components and nutritional values. Medicinal mushrooms can be identified morphologically on the basis of their size, color (white, black, yellow, brown, cream, pink and purple-brown, etc.), chemical reactions, consistency of the stalk and cap, mode of attachment of the gills to the stalk, and spore color and mass, and further identified at a molecular level by Internal Transcribed Spacer (ITS) regions of gene sequencing. There are also other methods that have recently begun to be used for the identification of mushrooms such as high-pressure liquid chromatography (HPLC), nuclear magnetic resonance spectroscopy (NMR), microscopy, thin-layer chromatography (TLC), DNA sequencing, gas chromatography-mass spectrometry (GC-MS), chemical finger printing, ultra-performance liquid chromatography (UPLC), fourier transform infrared spectroscopy (FTIR), liquid chromatography quadrupole time-of-flight mass spectrometry (LCMS-TOF) and high-performance thin-layer chromatography (HPTLC). Lately, the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technique is also used for the identification of fungi.

Key Finding and Conclusion

Medicinal mushrooms possess various biological activities like anti-oxidant, anti-cancer, anti-inflammatory, anti-aging, anti-tumor, anti-viral, anti-parasitic, anti-microbial, hepatoprotective, anti-HIV, anti-diabetic, and many others that will be mentioned in this article. This manuscript will provide future direction, action mechanisms, applications, and the recent collective information of medicinal mushrooms. In addition to many unknown metabolites and patented active metabolites are also included.

Heat stress in macrofungi: effects and response mechanisms

Temperature is one of the key factors that affects the growth and development of macrofungi. Heat stress not only negatively affects the morphology and growth rate of macrofungi, but also destroys cell structures and influences cell metabolism. Due to loosed structure of cell walls and increased membrane fluidity, which caused by heat stress, the outflow of intracellular nutrients makes macrofungi more vulnerable to invasion by pathogens. Macrofungi accumulate reactive oxygen species (ROS), Ca²⁺, and nitric oxide (NO) when heat-stressed, which transmit and amplify the heat stimulation signal through intracellular signal transduction pathways. Through regulation of some transcription factors including heat response factors (HSFs), POZCP26 and MYB, macrofungi respond to heat stress by different mechanisms. In this paper, we present mechanisms used by macrofungi to adapt and survive under heat stress conditions, including antioxidant defense systems that eliminate the excess ROS, increase in trehalose levels that prevent enzymes and proteins deformation, and stabilize cell structures and heat shock proteins (HSPs) that repair damaged proteins and synthesis of auxins, which increase the activity of antioxidant enzymes. All of these help macrofungi resist and adapt to heat stress. KEY POINTS: • The effects of heat stress on macrofungal growth and development were described. • The respond mechanisms to heat stress in macrofungi were summarized. • The further research directions of heat stress in macrofungi were discussed.