Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with the roots of nearly all land-dwelling plants, increasing growth and productivity, especially during abiotic stress. AMF improves plant development by enhancing nutrient acquisition, such as phosphorus, water, and mineral uptake. AMF also improves plant tolerance and resilience to abiotic stressors like drought, salt, and heavy metal toxicity.
These benefits come from the arbuscular mycorrhizal interface, which allows fungal and plant partners to exchange nutrients, signaling molecules, and protective chemical compounds. Plants’ antioxidant defense systems, osmotic adjustment, and hormone regulation are also affected by AMF colonization. These responses promote plant performance, photosynthetic efficiency, and biomass production in abiotic stress conditions.
As a result of its positive effects on soil structure, nutrient cycling, and carbon sequestration, AMF contributes to the maintenance of resilient ecosystems. The effects of AMFs on plant growth and ecological stability are species- and environment-specific. AMF’s growth-regulating, productivity-enhancing role in abiotic stress alleviation is reviewed here.
More research is needed to understand the molecular mechanisms that drive AMF-plant interactions and their responses to abiotic stresses. AMF triggers plants’ morphological, physiological, and molecular responses to abiotic stress. Water and nutrient acquisition, plant development, and abiotic stress tolerance are improved by arbuscular mycorrhizal symbiosis.
In plants, AMF colonization modulates antioxidant defense mechanisms, osmotic adjustment, and hormonal regulation. These responses promote plant performance, photosynthetic efficiency, and biomass production in abiotic stress circumstances. AMF-mediated effects are also enhanced by essential oils (EOs), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), hydrogen peroxide (H2O2), malondialdehyde (MDA), and phosphorus (P).
Understanding how AMF increases plant adaptation and reduces abiotic stress will help sustain agriculture, ecosystem management, and climate change mitigation. Arbuscular mycorrhizal fungi (AMF) have gained prominence in agriculture due to their multifaceted roles in promoting plant health and productivity. This review delves into how AMF influences plant growth and nutrient absorption, especially under challenging environmental conditions.
We further explore the extent to which AMF bolsters plant resilience and growth during stress. Industrialization, urbanization, and globalization are shrinking the arable lands and declining agricultural production, leading to increased food demand for the rapidly growing population. In addition, changing climatic conditions have resulted in extreme weather conditions that ultimately lead to more droughts, high temperatures, and floods, affecting the food supply from agricultural systems.
Sustainable agriculture, or agricultural systems that bind the use of natural resources to produce food in a way that minimizes the adverse effects of the production process on the environment, is crucial to achieving this balance. It is becoming increasingly clear that soil is an integral part of food production and a critical resource that must be managed carefully to ensure long-term economic and environmental sustainability.
A comprehensive overview of what we currently know about AMF and how it may be used to improve crop yields under both optimal and stressed conditions is provided in this study. AMF was discussed as a way to improve crop growth. By secreting more enzymes, bacteria facilitate nitrogen uptake by plants. However, there is an issue since oxygen destroys nitrogen-free enzymes. To combat this issue, bacteria interact with plants to develop a nodule root structure.
Many studies have demonstrated the beneficial effects of AMF on crop yields, which will be discussed in this review with an in-depth analysis. These symbiotic relationships allow plants to obtain nutrients from the unavailable soil. In addition to boosting plant growth and well-being, fungi absorb phosphorus and other essential minerals from the soil.
Due to the release of enzymes by the fungus, the plant can gain access to nutrients that would otherwise be inaccessible to it. Moreover, the fungal part releases several hormones that aid the plant in developing an extensive root system. In exchange, the plant provides the fungus with sugar, the main component for energy and survival.
Agroecosystems are designed to minimize the number of external inputs, such as pesticides, chemical fertilizers, and water, while maximizing natural resources, such as sunlight and soil nutrients. This makes them more sustainable than traditional farming methods. For instance, beneficial bacteria can fix nitrogen from the atmosphere, make it available to plants, and suppress soil-borne diseases.
They establish a mutualistic relationship with plant roots, providing essential minerals and water from the soil in exchange for photosynthetically fixed carbon from the plant. Furthermore, these fungi are also known to provide critical benefits to the plants they associate with, such as improved water and nutrient uptake, increased resistance against diseases, and nutrient mobilization from organic substrates.
These interactions can lead to dramatic changes in the composition, structure, and functioning of plant communities, and a comprehensive understanding of these processes is essential for successful ecosystem conservation and management. The imbalance of beneficial microorganisms caused by the disruption in the microbial population has led to soil deterioration and decreased crop production.
Alterations in the composition of microbial communities can also result in changes in soil nutrient cycling and a reduction in soil water retention, leading to further soil degradation. Microbes are essential for sustainable soil fertility management in nutrient cycling, pest management, and soil structure.
This study aims to draw attention to the significant role that endomycorrhiza symbiosis can play as a provider of ecosystem services to ensure crop yield and assist in developing sustainable agriculture systems. Consequently, the general goal of this study is to review the work of AM growths on agricultural yield efficiency and biological system administration.
Understanding microbial interactions and how they interact with plants is critical to developing sustainable management of soil fertility and crop production. Beneficial microorganisms like Arbuscular mycorrhizal fungi enhance soil fertility and the ability of plants to uptake more nutrients. In return, the microbes receive a continuous supply of nutrients, allowing them to flourish and provide a healthier environment for the proper growth of plants.
Plant roots often provide nitrogen and other essential minerals to their associated fungi, while the fungi provide the plants with the essential nutrients and water. Moreover, AMF can also help plants resist environmental stress, such as drought and soil salinity, resulting in higher levels of plant growth and an increased rate of survival.
By making the most of these technologies, smallholder farmers can not only maximize the yields of their crops but also enhance the sustainability of their farming practices for future generations. Arbuscular mycorrhizal isolates provide a range of agroecosystem services to important crops among smallholder farmers, and such services have been well documented in numerous recent studies.
Arbuscules, internal fungal structures in the root cortical cells, allow arbuscular mycorrhizal (AM) fungi to form strong relationships with a host plant. According to current estimates, AM fungus started cooperating with host plants between 400 and 480 million years ago, facilitating the first terrestrial plant colonization of the land.
Approximately eighty per cent of terrestrial plant species are in relationships of close symbiosis with AM fungus for various factors that benefit plants, such as nutrient acquisition, crop mass, yield increases, and reduced stress from abiotic pressures. AMF is a crucial and helpful gathering of soil accumulation that may significantly increase crop efficiency and ecological continuity in the production methods of new plants.
Endomycorrhiza fuofs allows the start of a mutualism relationship along with the root structure of eighty per cent of plant families; it just does not better the development of plants via enhanced absorption of phosphorus (P) available in the soil and other on-labile mineral nutrients necessary for the development of the plant, but it also has ‘unhealthy’ effects on maintaining the collected soil, intended to stop erosion, and overcomes stress in plants due to abiotic and biotic factors.
AM fungi’s positive effects on plant execution and soil well-being are fundamental for agricultural ecosystems to be managed sustainably. However, as the “first green revolution,” beneficial soil microbes, generally, and AM in particular, have received significantly less attention.
Even though some offerings stand outside the marketplace and are hard to measure, the lowest approximate equivalent or outstrip worldwide gross countrywide outcomes; a price tag of USD 190 billion has been calculated based on the value of goods and services provided by nature, including clean water, fertile soils, and pollination. This is double the worth of the gross national items of the world.
According to present research, two critical environmental offerings, ‘formation of the soil’ and ‘cycling of nutrients, were expected to highlight USD 17.1 and 2.3 trillion US dollars. Simultaneously, most nations consume their charge frameworks to save the climate by limiting the number of exercises involved in the pollution they allow (such as the carbon tax) or to motivate the growth of rules that are in favour of the environment (Ecological Tax Reform).
Costa Rica is the first nation to made a countrywide attempt to safe atmosphere offerings. In 1996, this nation followed the rule (Forestry Law No. 7575), spotting four vital services supplied through the public woods: carbon elimination, hydrological offerings, biodiversity security, and attractive charm. The rule set up a structure for the fee for atmosphere offerings, as outlined in a program authorized by the pagos por service Ambien (PSA) and managed through the fund provided by the National Forestry (FONAFIFO), which includes landlords and all other succeeding customers of the earth who agreed to charge environment offerings for twenty years and offer opposition through replanting, continuous management, conservation, and strategies of rebirth.
The availability of farming goods and environmental services is essential to human existence and the standard of life. Nevertheless, new farming techniques that have significantly enhanced the world’s food contribution have unintentionally negatively affected the environment and resources. In the context of advancement, new and beneficial procedures are needed to operate the Earth’s surrounding services and counter the lack of effort to hold necessary outcomes for renewable food manufacturing in the face of the enhancing populace worldwide.
Horticulture is the most significant connection between people and the climate; accommodating yield creation and natural respectability, reasonable harvest, and crop production is difficult for agribusiness and predetermination for landowners. This demonstrates extending yield executives methodologies that enhance soil fertility, organic assortment, and crop production through developing agroecosystems that favour standard ecological methods and support efficiency in the long term.
Ecological administrations sustain soil attributes and plant well-being; soil flexibility in this environment is incredibly relevant. Specifically, soil microorganisms that structure cooperative interactions with the roots of plants have attracted growing attention in rural examination and improvement since they provide a natural substitute to stimulate plant development and lower contributions to feasible editing arrangements.
The omnipresence of arbuscular mycorrhizal growths at the point of interaction among soil and plant roots makes them an essential and valuable association of soil biota. Their wholesome and non-dietary attributes significantly affect surrounding methods promoting farming yield creation and agroecological environmental administrations.
The proper management of environmental services provided by AM will positively influence the utilization and conservation of natural resources for the benefit of human societies. Biomolecules have a backbone made of carbon, which is a necessary component of living organisms. Nevertheless, too much CO2 in the atmosphere is thought to be dangerous. Thus, it is involved among the primary greenhouse gases.
Carbon sequestration captures carbon dioxide to lower atmospheric carbon dioxide levels. The amount of carbon dioxide in the atmosphere directly impacts global climate changes, seriously threatening the entire biosphere. The amount of CO2 has steadily risen in the atmosphere, with an average of approximately 385 ppm.
Some research teams have been performing evaluations to determine the most effective carbon sequestration technologies for a few decades. Two primary geological and biological carbon sequestration processes have been documented. One of the critical processes of biological carbon sequestration is the assimilation of atmospheric CO2 through the biological activity known as photosynthesis.
To reduce atmospheric CO2 levels, microbe-mediated CO2 uptake in the soil and plants is a crucial problem. The increase in photosynthetic rate is caused by bacterial populations in the leaf endosphere, phyllo sphere, and rhizosphere, despite photosynthesis being a natural process that consumes atmospheric CO2.
Similar to how mammals develop symbiotic connections with microorganisms and have probiotics, plants have a variety of microbial communities and do the same. Microbial communities linked with plants impact the operation of intricate bio-networks, such as complete food chains in many ecosystems.
Entophytic and endophytic interactions between plants and microorganisms have generally been discovered. However, these interactions are context-dependent, bidirectional, and complicated. Despite some understanding of the relationship between plants and bacteria, scientific research has restricted attempts to use microbes as bio-stimulants or biofertilizers.
Plant-associated microorganisms’ different molecular pathways to increase photosynthetic rate are being investigated. By supplying specific bioactive chemicals, endophytes colonized in the interior tissues of plant parts help improve plant growth, yield, and disease resistance. In contrast, the host plant provides carbon substrates to the microorganisms.
Interestingly, a certain microbial strain prefers to colonize the rhizosphere when atmospheric CO2 levels are rising over those of other strains. Improving carbon absorption by plants that rely on particular microbial strains would also help lower atmospheric CO2.
For instance, the bacterial strain Pseudomonas simiae colonizes the rhizosphere much more quickly than the strain P. putida when the CO2 concentration is high. In addition, well-documented microbe-mediation increases in photosynthetic rate in the tissues of plant leaves.
The rhizosphere’s microbial population is solely reliant on plant signals. In addition to their fundamental tasks, plants’ roots are involved in various additional systems. Organic macromolecules called “root exudates” are discharged into the rhizosphere by roots, making up 5 to 40% of the plant’s photosynthetically absorbed carbon.
For instance, the root exudates contain substances like citric acid, fumaric acid, flavonoids, tryptophan, etc., that function as signaling molecules and draw advantageous microorganisms to the rhizosphere. Under high CO2 conditions, plant roots release root exudates that attract beneficial microbes to colonize in the rhizosphere or within the plant tissues.
Similarly, when plants’ carbon sinks, such as respiration, growth, and storage, require them to store photosynthetically fixed carbon, they enlist the help of beneficial bacteria to improve the rate at which they fix carbon through photosynthesis. When bacteria colonize the root system, root exudates play a role in the selection processes that favor certain bacteria over others.
The photosynthetic pigments chlorophyll and carotenoids are the most abundant in the plant’s aerial portions, and it has been suggested that bacteria work as bio-stimulants to increase this concentration. By increasing the chlorophyll content, plant growth-promoting rhizobacteria (PGPR), Enterobacter sp., considerably accelerates the development of the Okra plant overall.
Similar advantages can be attained by intentionally introducing fungal endophytes into the plants. For instance, adding fungal endophytes to Coleus forskolin plants increased their yield by increasing their total photosynthetic rate. Microbes increase chlorophyll content to increase the photosynthetic rate even under stress circumstances caused by metal elements.
Lycopersicon esculentum, a plant growing under cadmium (Cd) stress, has a dramatically higher total chlorophyll content after being inoculated with P. aeruginosa or Burkholderia gladioli, according to Khanna et al.’s (2019) analysis. Microbes connected with plants can increase the expression of genes involved in photosynthesis and boost the effectiveness of the enzymes needed for biological carbon fixation.
In the plant Sedum alfredii, growing under Cd stress, Wu et al. (2018) showed that bacterial inoculants might enhance the effectiveness of photosynthetic enzymes including Rubisco, Ca2+-ATPases, and Mg2+-ATPase and upregulate the expression of photosystem related genes (SaPsbS and SaLhcb2).
One of the primary purposes of stomata is carbon fixation, which enables the plant to absorb CO2 and exhale O2. There have been claims that bacteria can control stomatal conductance in plant leaves. Interestingly, some research discovered enhanced stomatal conductivity, while others found that it was reduced when the plants were colonized by certain microbes.
Carbon is removed from the environment and deposited in the soil due to increased CO2 sequestration from the air, improved photosynthesis, and augmented soil organic matter. By boosting plant root development, microbial inoculants improve photosynthesis and deposit soil organic matter in the rhizosphere.
Plant growth hormones are produced by root-associated microorganisms, enhance the expression of genes involved in root growth and development, and increase the concentration of photosynthetic pigments, chlorophyll, and carotenoids, all of which contribute to considerable organic matter deposition in the soil in the form of increased root yield.
Reactive oxygen species (ROS) are produced in leaf tissues when photosynthetic pigments are overexcited or when plants are exposed to environmental challenges. The released ROS reduces the photosynthesis rate by inhibiting phot
