Outlooks of Nanotechnology with Mycorrhizae

Abstract

Mycorrhizae play a vital role in providing plants with essential macro and micro-mineral elements and protecting them from pathogen infections. Enhancing the plant’s resistance to environmental stress like drought, salinity, and heavy metals, along with enhancing soil structure through the secretion of glycoprotein compounds known as Glumalin, are some benefits. Additionally, plants treated with mineral nanoparticles and mycorrhiza exhibit improved growth, yield, and biochemical characteristics. Also, the plants treated with mineral nanoparticles and mycorrhiza showed better growth, yield, and biochemical properties. Mycorrhiza can also be used as a base material for the synthesis of nanoparticles under green synthesis mode. Thus, nanotechnology and biofertilization are steps friendly environmental.

1. Introduction

Mycorrhizae are fungi that form a symbiotic benign relationship with higher plants [1]. These associations vary widely in functions and structure, and there are several types of mycorrhizae, but the most abundant is arbuscular mycorrhizal (AM) [2]. It can supply nutrients to plants, even when levels are low in the soil, particularly vital nutrients like phosphorus (P) and nitrogen (N), as well as other elements like copper, zinc, and iron. In return, plants allocate 10–20% of their photosynthesis to fungi—mycorrhizae shield roots from harmful fungi in the soil. Arbuscular mycorrhizal fungi can establish a symbiotic bond with 85% of plant families, contributing significantly to ecosystem sustainability [3]. AM fungi are obligate mutualists belonging to the phylum Glomeromycota [4]. Fungal hyphae enter root epidermal cells and proceed to cortex cells, where they form vesicles, arbuscles, and coils, establishing a network of hyphae outside the root (extra-radical hyphae) that enhances soil texture and water relations within the plant’s root system [5]. AM fungi produce a type of glycoprotein named Glyoxalin, which contributes to alleviating soil degradation and inoculating plants. AM fungi give them the ability to withstand extreme conditions of salinity, drought, temperature, and lack of mineral nutrients [6]. With these good qualities, mycorrhizae have entered organic agriculture, but they are insufficient and unrewarding in all regions and under all circumstances, and other supplements must be used, such as mineral and organic fertilizers, in addition to all types of control against diseases and insects. Nanotechnology has entered every detail of life, including agriculture, to benefit from its potential to solve many problems of environmental pollution, lack of nutritional elements and minerals, and increasing production and yields. Both humans and plants need nutritional elements for growth and development, and these elements are absorbed through the root plants and transported to all parts of the plant, so that humans can eat them as suitable food [1].

In pea plants, the synergistic activity between nanoparticles and mycorrhizae caused rising of acid phosphatase, alkaline phosphatase, catalase, and peroxidase as biochemical parameters. The combination that is used is Nano-ZnFe₂O₄ and arbuscular mycorrhiza (AM), in addition to improving N, P, K, and Mg uptakes [2]. The coupling between ZnFe₂O₄ NPs and AM fungi in nano agricultural applications Improved the physiological, growth, and biochemical parameters of pea plants [3]. The use of nanofoliar fertilizers and nanofertilizers extracted from marine organisms with mycorrhizal fungi enhanced the nutrient concentration, growth, and production yield of wheat [4]. The combined application of foliar spray AM fungi (250 g inoculum/vine) and seaweed extract (1%) with nano-zinc oxide particles (50 ppm) three times after the bud burst stage on sweet grapevines resulted in improved vegetable growth traits, nutritional status, yield, and cluster quality attributes. The interaction between mycorrhizae, nanocomposites, and their challenges, particularly in combating various microorganisms like fungi, will be the central focus of this chapter, highlighting both the challenges and advantages.

2. Management of drought stress using nanofertilizers and mycorrhizae

In arid and semi-arid regions, successive droughts resulting from climate change have led to abiotic stress, causing poor plant growth and low productivity [7]. Lack of soil moisture can have limitation effects on hydraulic and nutritional conductivity, especially phosphorus (P), potassium (K), nitrogen (N), ionic balance, and gas exchange; it damages photosynthetic pigments and reduces the photochemical efficiency of photosystem II (PSII) [8, 9, 10]. In addition, reactive oxygen species (ROS) are produced and can damage cell structures such as carbohydrates, nucleic acids, lipids, and proteins and alter their functions, creating oxidative stress [11]. To maintain a plant’s water balance, stomata arrange leaf diffusive conductance to control the flow of gases between the stomatal aperture leaf and the atmosphere, reducing the diffusion of carbon dioxide (CO₂), leading to a decline in photosynthetic performances and chlorophyll pigment concentration, as well as accumulation of primary metabolites such as soluble sugars and proteins [12]. For these reasons, the combination of plants and AM fungi could be an appropriate strategy for the sustainable management of aridity stress. In pot experiments, wheat plants (Triticum aestivum) inoculated with arbuscular mycorrhizal fungi (AMF) showed an increase in relative water content in both leaves and soil, which indicates resistance to drought stress through the ability of AMF to penetrate deep into the soil to provide the necessary moisture. The AMF plant colonization was less severe than the drought stress damage to the photochemistry, function, and structure of PSII and PSI [13]. Nanofertilizers are remarkable tools in agriculture that help to progress crop growth, yield, and quality parameters [14]. The comparison between the nano and conventional mineral nutrients fertilizers results in increased nutrient cause toxicity and inhibits crop growth, compared to the use of fertilizers and nano-nutrients, which improve the growth and yield without toxicity [15]. Nanofertilizers supply and expand the surface area to perform many types of metabolic reactions, leading to an increased rate of photosynthesis, dry matter, and yield of the crop [14]. The optimum dose and concentration applied are important to get the maximum growth and yield of the crop; otherwise, they also have an inhibitory effect if they exceed the optimum one [15]. The combined treatment carbon nanoparticles, arbuscular mycorrhiza, and compost (Com-AMF-CNPs) on maize plant crops under drought stress increased the levels of oxalic and succinic acids (by 100%) as indicators of enhanced amino acids level such as the antioxidant and omso-protectant proline, increases in fatty acids such as myristic, palmitic, arachidic, docosanoic, and pentacosanoic (110, 30, 100, and 130%, respectively), compared with untreated plants, polyamine biosynthesis amino acids and increased spermine and spermidine synthases, ornithine decarboxylase, and adenosyl methionine decarboxylase in treated maize [16]. Drought stress significantly reduced maize growth and photosynthesis and altered metabolism [17]. Arbuscular mycorrhizal fungi (AMF) and titanium dioxide (TiO₂) have been proven to mitigate the impacts of drought stress on plants (Salvia officinalis L.). Combining biofertilizer and nanoparticles (TiO₂ + AMF) offers a sustainable approach to enhancing essential oils (EO), boosting productivity, and improving the quality of sage plants under drought-stress conditions [18]. Transmission electron microscopy and X-ray analyses were used to detect the combination between Ferrous nanoparticles (FeNPs) and AMF (Glomus) to enhance photosynthesis and water efficiency, in addition to increasing uptake of ‘Fe-NPs,’ which means the presence of elements in seeds and roots enhanced the growth-promoting and drought-tolerant [19].

3. Reducing salinity stress using nanomaterials and mycorrhizae

Salt stress is a pioneer agricultural trouble all over the world; reducing salinity stress using nanomaterials and mycorrhizae has an effect on the functioning of growth and physiology of crop plants [20]. Soil salinity affects the rate of plant growth by reducing the rate of photosynthesis and stomatal conductivity and inhibiting antioxidant enzymes [21]. Under salinity stress conditions, using arbuscular mycorrhizal fungi (AMF) enhances crop plant growth and physiological performance, increasing plant biomass, photosynthetic activity, water potential, and selective uptake of nutrients [22]. As a response to salinity stress, AMF increases antioxidant defense mechanisms and promotes salinity tolerance in crop plants [23]. AMF plays an important role in plant cell osmotic balance by regulating the Na and K ratio and enhancing the synthesis of many osmolytes such as proline and glycine betaine [24]. AM fungi may be able to keep plant cells from salt stress, but there is a decline in propagule production and AM colonization under high salinity conditions [25]. Therefore, the combination of nanoparticles and AMF resolved the problem, and the AMF community co-occurrence network complexity was enhanced by silver nanoparticle AgNPs [26]. To improve production under salinity conditions, it is recommended to use nano-zinc oxide and mycorrhizae [27]. In the salinity condition, the interaction between nano-zinc oxide and AM fungi showed significantly increased K+, reduced Na+ uptake, and increased wheat yield [28]. In addition, watering the wheat plant with different levels of salt water may have an effect on the physiological properties and yield, but the use of the interaction between mineral and nano-zinc and mycorrhizal fungi improved the physiological properties, yield, concentration of some nutrients, the K/Na ratio, and the protein percentage in the crop grains [29]. The combination of nano-zinc fertilizer and mycorrhizae has a notable impact on the activity of (CAT), (SOD), and (POD) enzymes when exposed to varying levels of saline water during irrigation. This impact becomes more pronounced as the salinity levels in the irrigation water rise (Tables 1–3) [30]. In a greenhouse environment, silicon nanoparticles (Si-NPs) at different concentrations (0, 30, and 60 mg/L) along with various biofertilizers were examined for their potential to enhance wheat’s resistance to salinity stress by evaluating antioxidant activity. The study involved different salt concentrations (0, 35, 70, and 105 mM), and the outcomes indicated that bio-fertilizers and Si-NPs boosted parameters, including plant leaf water potential, soluble protein, soluble sugar, catalase, peroxidase, and polyphenol oxidase levels. The application of both single and combined bio-fertilizers with Si-NPs showed improvements in physiological aspects such as stomatal conductance, electrical conductivity, electrolytic leakage, and proline content. Furthermore, the use of Si-NPs and bio-fertilizers led to increased wheat grain yield under salinity stress conditions by enhancing physiological and biochemical characteristics. The most favorable results in terms of grain yield and reduced malondialdehyde and hydrogen peroxide levels were observed with the combined application of biofertilizers and Si-NPs at a concentration of 60 mg/L under normal salinity levels [31]. Salinity stress limits crop production. The use of silicon dioxide nanoparticles (SiO₂-NPs) along with the inoculation of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) with wheat helps mitigate the negative impacts of salinity stress. This combined approach enhances physiological parameters such as leaf area index, chlorophyll fluorescence, anthocyanin, and chlorophyll index. Coinoculation of AMF and PGPR, along with 60 mg/L SiO₂-NPs, leads to improved Si, P, and K+ uptake, reduced Na+ uptake, and ultimately, increased grain yield [32].

Mycorrhiza; M (20 g/pot)	Type of zinc; Zn (15 mg L^−1)		Salinity levels of irrigation water; S (dS m^−1)				Average of mycorrhiza
			S1	S2	S3	S4
M0	Zn0		4.97	4.80	6.11	10.19	6.19
	Zn1		3.70	4.23	4.78	7.86
	Zn2		3.89	6.88	8.52	8.36
M1	Zn0		5.03	5.35	8.60	8.80	7.03
	Zn1		3.67	6.48	9.16	8.93
	Zn2		4.89	6.62	7.39	9.41
Salinity levels of irrigation rate			4.36	5.73	7.43	8.92
Zinc rate			Zn0	Zn1	Zn2
			6.73	6.10	7.00
M. Zn			Zn0	Zn1	Zn2
M0			6.52	5.14	6.91
M1			6.95	7.06	7.08
M. S			S1	S2	S3	S4
M0			4.19	5.30	6.47	8.80
M1			4.53	6.15	8.38	9.05
S. Zn			S1	S2	S3	S4
Zn0			5.00	5.07	7.35	9.49
Zn1			3.68	5.36	6.97	8.39
Zn2			4.39	6.75	7.96	8.89
L.S.D0.05	M	Zn	S	Zn. M	S.M	S. Zn	S. Zn.M
	0.405	0.496	0.573	0.702	0.810	0.992	1.403
M0 = without mycorrhiza *; M1 = with mycorrhiza; Zn0 = without zinc; Zn1 = mineral zinc; Zn2 = nano-zinc		S1 = 2 dS m^−1; S2= 4 dS m^−1; S3 = 6 dS m^−1; S4 = 8 dS m^−1

Table 1.

The interaction between mycorrhiza, zinc, and different levels of saline water in CAT enzyme (unit g. protein⁻¹ fresh weight) of wheat crop.

Mycorrhiza M (20 g/pot)	Type of zinc Zn (15 mg L^−1)		Salinity levels of irrigation water S (dS m^−1)				Average of mycorrhiza
			S1	S2	S3	S4
M0	Zn0		3.81	3.96	3.15	5.21	3.75
	Zn1		2.91	3.57	3.99	4.36
	Zn2		3.08	3.20	4.75	3.03
M1	Zn0		4.67	3.31	3.19	3.46	3.28
	Zn1		1.20	2.91	3.01	3.76
	Zn2		3.78	3.43	3.00	3.69
Salinity levels of irrigation rate			3.24	3.40	3.52	3.92
Zinc rate			Zn0	Zn1	Zn2
			3.84	3.21	3.49
M. Zn			Zn0	Zn1	Zn2
M0			3.27	3.58	3.96
M1			3.21	3.21	3.05
M. S			S1	S2	S3	S4
M0			3.27	3.58	3.96	4.20
M1			3.21	3.21	3.05	3.64
S. Zn			S1	S2	S3	S4
Zn0			4.24	3.64	3.17	4.33
Zn1			2.05	3.24	3.50	4.06
Zn2			3.43	3.31	3.88	3.36
L.S.D0.05	M	Zn	S	Zn. M	S.M	S. Zn	S. Zn.M
	0.420	0.514	0.594	0.727	0.840	1.029	1.455
M0 = without mycorrhiza *; M1 = with mycorrhiza; Zn0 = without zinc; Zn1 = mineral zinc; Zn2 = nano-zinc		S1 = 2 dS m^−1; S2 = 4 dS m^−1; S3 = 6 dS m^−1; S4 = 8 dS m^−1

Table 2.

The interaction between mycorrhiza, zinc, and different levels of saline water in SOD enzyme (unit g. protein⁻¹ fresh weight) of wheat crop.

Mycorrhiza M (20 g/pot)	Type of zinc Zn (15 mg L^−1)		Salinity levels of irrigation water S (dS m^−1)				Average of mycorrhiza
			S1	S2	S3	S4
M0	Zn0		1.979	2.435	2.328	2.917	2.304
	Zn1		1.837	2.421	2.523	2.373
	Zn2		1.876	2.273	2.238	2.453
M1	Zn0		2.492	2.452	2.135	2.381	2.175
	Zn1		1.463	2.129	2.574	2.964
	Zn2		1.441	1.723	1.902	2.450
Salinity levels of irrigation rate			1.848	2.239	2.283	2.590
Zinc rate			Zn0	Zn1	Zn2
			2.390	2.285	2.045
M. Zn			Zn0	Zn1	Zn2
M0			2.415	2.288	2.210
M1			2.365	2.282	1.879
M. S			S1	S2	S3	S4
M0			1.897	2.376	2.363	2.581
M1			1.799	2.101	2.203	2.598
S. Zn			S1	S2	S3	S4
Zn0			2.235	2.444	2.231	2.649
Zn1			1.650	2.275	2.548	2.668
Zn2			1.658	1.998	2.070	2.452
L.S.D0.05	M	Zn	S	Zn. M	S.M	S. Zn	S. Zn.M
	n.s	0.2325	0.2684	0.3288	0.3796	0.4649	0.6575
*M0 = without mycorrhiza; M1 = with mycorrhiza; Zn0 = without zinc; Zn1 = mineral zinc; Zn2 = nano-zinc		S1 = 2 dS m^−1; S2 = 4 dS m^−1; S3 = 6 dS m^−1; S4 = 8 dS m^−1

Table 3.

The interaction between mycorrhiza, zinc, and different levels of saline water in POD enzyme (unit g. protein⁻¹ fresh weight) of wheat crop.

4. Bioremediation of heavy metals using nanomaterials and mycorrhizae

Heavy metal elements like copper (Cu), lead (Pb), mercury (Hg), and zinc (Zn) have made their way into the human living environment through various pathways such as atmospheric precipitation, dust, transportation, and activities like agriculture, industrial wastewater, and vehicle emissions [33, 34, 35], resulting in serious heavy metal pollution that can accumulate in crops and animals, affecting their growth and poisoning and eventually entering the human body through the food chain and food web, endangering human health and even life [36]. A variety of diseases can arise from the accumulation of heavy metal elements in the human body, such as cancers [37]. Improving soils and waste contaminated with heavy metals is crucial for achieving a clean and sustainable environment. Arbuscular mycorrhizal fungi (AMF) play a role in alleviating the harmful effects of different pollutants on plants [38]. Copper oxide nanoparticles (nano-CuO) are considered a growing environmental concern for Canna indica seedlings. In this study, AMF inoculation effectively alleviates the stress caused by nano-CuO by boosting antioxidant enzyme activities and reducing ROS levels in both the leaves and roots of C. indica. This led to an upregulation of antioxidant genes, a decrease in Cu levels within the seedlings, and an increase in the expression of Cu transport genes and metallothionein genes [39]. Engineered nanomaterials (ENMs) are on the rise across various sectors, leading to a significant risk of ENMs entering the natural environment. Rhizomicroorganisms, such as arbuscular mycorrhizal fungi (AMF), play a crucial role in immobilizing ENMs, reducing phytoaccumulation, enhancing host plant growth, triggering system-wide protection against ENMs stress, and indirectly mitigating the harmful effects of ENMs on host plants. The combined action of plants and AMF could offer a cost-effective and environmentally friendly approach to controlling potential ENM contamination sustainably [40]. AMF’s ability to reduce the negative effects of elevated AgNP levels, such as increasing plant growth and improving ecological behaviors, was enhanced, resulting in lower Ag levels and reduced antioxidant enzyme activity in plants [41]. Maize (Zea mays L.) exhibited varying responses when exposed to different concentrations of Silver nanoparticles (AgNPs) (0, 0.025, 0.25, and 2.5 mg/kg) both in the presence and absence of arbuscular mycorrhizal (AM) fungi and soil microorganisms. The incorporation of AM fungi was found to play a crucial role in ameliorating the adverse effects induced by AgNPs phytotoxicity, thereby enhancing the mycorrhizal colonization, biomass, and phosphorus (P) uptake in maize plants. Furthermore, the inoculation of AM fungi was associated with a reduction in the toxicity of AgNPs toward soil microbial communities, leading to an increase in bacterial diversity and prompting alterations in the composition of the soil bacterial community. This shift in the soil bacterial community structure was attributed to the modulation of potential Ag transporter gene expressions and the collaborative interactions between the AM fungi and soil bacterial community [42]. Inoculating Spearmint plants with arbuscular mycorrhizal (AM) helped alleviate Cu toxicity caused by spraying 0.66 and 1.05 mg of elemental Cu per pot from Cu(OH)₂ nanowires, bulk Cu(OH)₂ (Kocide 3000), or ionic CuSO₄. This study illustrates that interactions between plants and microbes could enhance crop productivity and offer environmental advantages, highlighting the importance of assessing risks in crop systems that involve symbiotic microorganisms [43]. Soil microorganisms play a vital role in explaining the impact of iron oxide nanoparticles (Fe₃O₄NPs) across different concentrations (0.1, 1.0, and 10.0 mg/kg) on maize plants with or without AMF inoculation. No significant changes in soil biota or dissolved organic C (DOC) were observed in AMF-inoculated treatments. However, variations were noted in content levels under Fe₃O₄NPs treatment alone. These findings suggest that AMF can modify the effects of Fe₃O₄NPs on soil microorganisms, potentially through influencing plant growth and the release of organic matter from plant roots, as evidenced by the impact on DOC levels due to AMF [44].

5. Negatively influence nanomaterials interaction of mycorrhizae

Nanoparticles interact with mycorrhizae in various ways, some promoting colonization by AMF, while others hinder it [45]. Therefore, more detailed information is required on how arbuscular mycorrhizal fungi (AMF) interact with nanoparticles. High levels of Fe₃O₄NPs can disrupt the symbiotic relationship between AM fungi and plants, leading to carbon and phosphorus cycling deterioration in the soil. These impacts are detrimental to crop yield and soil fertility [46]. The ecological system influences the growth of mycorrhizal clover, with 0.01 mg/kg of AgNPs inhibiting growth, while 0.1 mg/kg of AgNPs leads to increased AgNP content. This affects the ability of AMF to alleviate AgNP stress by reducing Ag content and the activity of antioxidant enzymes in plants [41]. The ecosystem significantly influences the growth of mycorrhiza. A concentration of 0.01 mg/kg of nanosilver AgNPs suppresses mycorrhizal growth, while higher concentrations such as 0.1 mg/kg have adverse effects on the AM fungal colonization in the roots of Corn plants (Zea mays L.). This leads to reduced nutrient absorption, impacting the phosphorus cycle and uptake in the root zone, ultimately hindering plant growth and soil fertility [47].

6. Conclusions

Arbuscular mycorrhizal fungi (AMF) always associate with the roots of higher plants and form a mutualistic symbiosis with the roots of over 90% of plant species. The results of the study showed that the employment of nanofertilizers and mycorrhizal fungi had significant improvements in some physiological and chemical characteristics of plants and decreased the negative effects of drought stress, as well as their positive effect on antioxidants and cell death under salinity stress. Recently, a revolution has been created in the world of nanotechnology, and its interaction with mycorrhizae has resulted in beneficial plant growth, biological enrichment, and improved connection of mycorrhizae with plants. Other challenges were negative, given that increasing the concentration of nanomaterials may lead to inhibiting mycorrhizal growth and infecting plant roots, which is worth studying in order to find the best that deserves study in order to find the best ways for this relationship. Hence, in this chapter, we concentrate on the effect of various nanoparticles combined with AMF on some physiological characteristics of plants under stress and the role of nanoparticles in positive and negative relationships.

Acknowledgments

To the administration of the University of Kerbala, and the College of Education for Pure Sciences for the support.

Conflict of interest

The authors declare no conflict of interest.

Dedication

To my dear ones.

My late husband, Professor Dr. Abdoun Hashim Alwan, Thanks and mercy.

My dear children.

Zainab, Zaid and Zeki.