Arbuscular Mycorrhizal Fungi Mitigate Crop Multi-Stresses Under Mediterranean Climate: A Systematic Review

Abstract

Agricultural systems in Mediterranean-type climates are increasingly threatened by drought, salinity, extreme temperatures, heavy metal contamination, and pathogen pressure, all of which undermine crop productivity and agroecosystem stability. In this context, arbuscular mycorrhizal fungi (AMF), natural symbionts of most terrestrial plants, emerge as key biological agents capable of enhancing crop resilience. Following PRISMA guidelines, this systematic review synthesizes current knowledge on the role of AMF in mitigating abiotic and biotic stresses, highlighting their potential as a central component of sustainable Mediterranean agriculture. The available evidence demonstrates that AMF symbiosis significantly increases plant tolerance to multiple stressors across major crop families, including Poaceae, Fabaceae, Solanaceae, and Asteraceae. Under abiotic constraints, AMF improve water and nutrient uptake via extensive hyphal networks, modulate ion homeostasis under salinity, enhance tolerance to thermal extremes, and reduce heavy metal toxicity by immobilizing contaminants. Regarding biotic stresses, AMF induce systemic resistance to pathogens, stimulate secondary metabolite production that deters herbivores, and suppress parasitic nematode populations. Moreover, co-inoculation with other biostimulants, such as plant growth-promoting rhizobacteria, shows synergistic benefits, further improving crop productivity and resource-use efficiency. Overall, AMF represent an effective and multifunctional nature-based tool for improving the sustainability of Mediterranean agroecosystems. However, further research is required to evaluate AMF performance under simultaneous multiple stress factors, thereby reflecting real-world conditions and enabling a more integrated understanding of their agronomic potential.

1. Introduction

Over recent decades, the intensive reliance on chemical inputs in agriculture, together with the escalating impacts of climate change, has contributed substantially to ecosystem degradation [1]. Due to their intrinsic sensitivity to environmental fluctuations, plants are exposed to a wide spectrum of biotic and abiotic stressors—including drought, salinity, temperature extremes, heavy metal toxicity, nutrient imbalances, and pathogen infections [2,3,4]—which collectively contribute to yield reduction and impaired crop performance [5,6]. Among these, drought is particularly critical in the context of Mediterranean agriculture, where altered precipitation patterns and rising temperatures substantially constrain plant growth by impairing photosynthetic processes and disrupting nutrient homeostasis [1,7]. Within this context, the rhizosphere—the soil zone directly influenced by root activity—plays a central role, characterized by intense microbial interactions driven by root exudates that serve as key nutrient sources for microorganisms [8]. These exudates not only shape rhizosphere microbial communities but also modulate soil physical and chemical properties, thereby facilitating plant adaptation to environmental constraints [9,10]. Symbiotic interactions between plant roots, soil, and beneficial microorganisms enhance plant development by supporting nutrient acquisition, modulating signaling pathways, and contributing to soil health maintenance [11]. Rhizospheric microbial consortia promote nutrient cycling through nitrogen fixation, phosphorus solubilization, and the release of phytohormones, organic acids, and enzymes [12,13], while simultaneously protecting plants from phytopathogens [8,14]. Among beneficial microbes, arbuscular mycorrhizal fungi (AMF) have received particular attention due to their ability to establish symbiosis with the majority of terrestrial plants. AMF enhance soil structure and influence key biogeochemical processes. Their extensive extraradical hyphae significantly increase water and mineral uptake, particularly for low-mobility nutrients such as P, Zn, and Cu [13,15,16]. AMF also modulate root exudation, alter rhizosphere pH, and facilitate the mobilization of insoluble phosphorus, thereby improving plant phosphorus nutrition [10]. For instance, in rice, AMF can contribute up to 70% of total phosphorus uptake [17]. Beyond improving plant nutrition, AMF increase plant resilience to abiotic and biotic challenges. Under drought and salinity stress, they improve water and nutrient acquisition and promote the accumulation of osmoprotectants that support cellular homeostasis [18,19]. AMF also alleviate heavy metal toxicity through nutrient balancing and activation of plant tolerance mechanisms [20,21]. Mycorrhizal plants additionally display enhanced resistance to pathogens and improved tolerance to adverse environmental conditions [13,22]. The benefits of AMF are especially evident in low-input systems, such as organic agriculture, where improvements in photosynthesis and antioxidant capacity have been widely reported [16]. Given their multifunctional role, AMF are increasingly recognized as essential components of sustainable crop management practices [15]. They contribute to biotic stress reduction by priming plant defense pathways, particularly those regulated by jasmonic acid, and by enhancing secondary metabolite production [8,23]. Their synergistic interactions with plant growth-promoting rhizobacteria (PGPR) further improve nutrient use efficiency and support the transition toward agroecological and low-input farming systems [16,24,25]. These strategies can be integrated with sustainable practices such as organic amendments, cover crops, and conservation tillage to enhance soil functionality and crop stability in Mediterranean environments [26,27].

Agricultural Systems Under Mediterranean-Type Climates

Mediterranean climates encompass extensive agricultural areas in Southern Europe and North Africa—including Spain, Italy, Morocco, and Tunisia—as well as regions of South Africa, California, central Chile, Australia, and Central Asia (Figure 1). These climates are defined by pronounced summer drought, irregular rainfall patterns, and elevated evapotranspiration rates. According to the Köppen Cs classification, a Mediterranean climate is characterized by the following: (i) strong seasonal rainfall concentration, with at least 65% of annual precipitation occurring during the cool season (November–April) [28]; (ii) mild winters, with temperatures below 0 °C for less than 3% of the year [28]; and (iii) hydrological conditions suitable for dryland agriculture but insufficient to sustain dense coniferous or mesophytic forests [28]. These characteristics generate seasonal imbalances in water availability that often coincide with critical crop developmental stages [27]. Furthermore, alternating drought periods and intense rainfall events enhance soil erosion and nutrient leaching, particularly in sloped terrains and soils with low organic matter content [2,29]. In addition to water scarcity, Mediterranean soils frequently suffer from salinity, aridity, and nutrient deficiencies—particularly, limited phosphorus availability—which collectively constrain productivity and soil fertility [8,26]. High evapotranspiration further limits soil moisture retention, thereby reducing plant water-use efficiency and exacerbating crop stress. Consequently, Mediterranean-type agroecosystems can be regarded as hotspots of abiotic constraints, where recurrent drought, heat waves, soil salinization, and land degradation interact to impair crop performance and threaten yield stability [6,7]. When these stressors coincide with sensitive phenological stages, they intensify oxidative damage and disrupt plant water and nutrient relations [30,31]. In addition, Mediterranean cropping systems are exposed to substantial pressure from biotic stressors—including soil-borne and foliar pathogens, insect pests, and parasitic nematodes—whose incidence and severity often increase when plants are already constrained by drought and thermal extremes [2,3,32,33]. Given these interrelated limitations, which are increasingly intensified by climate change, there is a pressing need for sustainable, biologically based strategies capable of enhancing agroecosystem resilience. AMF have emerged as a promising nature-based solution in this regard, owing to their capacity to modulate plant physiological and biochemical responses under stress [34] and to enhance plant defense against pathogens and pests under biotic stress conditions [35,36,37]. Their integration into crop management has been shown to improve nutrient uptake, forage biomass, legume productivity, and soil health in resource-limited Mediterranean systems [38]. For example, the combination of micropropagation and AMF inoculation has been demonstrated to enhance phenolic compound accumulation in globe artichoke [39]. Nonetheless, the adoption of AMF by farmers remains limited, partly due to the lack of comprehensive, accessible guidelines on their application and expected agronomic outcomes. Moreover, the successful use of AMF requires adaptation to the specific hydrological and thermal dynamics of Mediterranean agroecosystems [38]. This review therefore aims to provide a comprehensive, multi-stress synthesis of current evidence on the contributions of AMF to crop resilience under Mediterranean climate conditions.

2. Materials and Methods

This systematic review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, resulting in the selection of 95 articles (Figure 2). The objective was to compile and critically synthesize research published over the last two decades concerning the role of arbuscular mycorrhizal fungi (AMF) in mediating crop responses to abiotic and biotic stresses within Mediterranean agroecosystems. A comprehensive literature search was performed using the Scopus, Web of Science, ScienceDirect, and Google Scholar databases. Peer-reviewed articles published up to July 2025 were considered. The search strategy relied on Boolean combinations of keywords related to the following:

(i) AMF (“arbuscular mycorrhizal fungi”, “AMF species”, “root-associated mycorrhizae”, “mycorrhizal symbionts”);

(ii) Stress conditions (“abiotic stress”, “biotic stress”, “drought”, “salinity”, “temperature extremes”);

(iii) Agroecosystem context (“Mediterranean agriculture”, “sustainable crop management”, “Mediterranean climate”);

(iv) Mediterranean crops of agronomic interest.

The selection of keywords was guided by their established relevance in the literature addressing AMF–plant interactions under environmental constraints. Studies were included according to the following criteria:

• Articles published in English in peer-reviewed journals;
• Studies evaluating the effect of AMF on crops exposed to abiotic or biotic stress, with explicit focus on Mediterranean climates or comparable environments;
• Research reporting quantitative or qualitative data on agronomic performance, physiological responses, nutritional parameters, or microbe–plant interactions associated with AMF.

Conversely, the following types of documents were excluded:

• Conference abstracts, book chapters, editorials, and non-peer-reviewed material;
• Studies not dealing with AMF in agricultural contexts;
• Articles lacking sufficient methodological detail or presenting unquantified or inconclusive outcomes.

The selection process was carried out in two phases. First, all retrieved documents were imported into reference-management software and screened for duplicates. Titles and abstracts were then reviewed to identify studies meeting the inclusion criteria. In the second phase, full-text screening was performed to confirm eligibility. Out of 395 initially identified articles, 77 were duplicates and 193 were excluded during the abstract screening due to lack of relevance. Following full-text evaluation, 90 studies met all criteria and were included in the final qualitative synthesis. The complete workflow is illustrated in the PRISMA flowchart (Figure 2) [39].

3. Results

3.1. Abiotic Stress and Its Mitigation Through Arbuscular Mycorrhizal Fungi

Arbuscular mycorrhizal fungi exhibit broad ecological tolerance and are distributed across a wide range of ecosystems and soil types, although their performance varies considerably among species and strains [42,43]. In Mediterranean-type environments, drought, salinity, temperature extremes, and heavy metal toxicity represent major limiting factors for crop productivity, primarily due to their disruptive effects on water uptake, ionic homeostasis, photosynthetic activity, and cellular integrity. While these stressors are intrinsically detrimental, AMF have been widely documented to alleviate their impacts by enhancing plant adaptive strategies and strengthening physiological resilience (

Table 1. Effects of arbuscular mycorrhizal fungi on abiotic stress in crops under Mediterranean climate.

Family	Species	Stress Agent	AMF	Effect Detail	Reference
Poaceae	Zea mays	High temperatures 42 °C	Rhizophagus irregularis, Funneliformis mosseae, Glomus spp.	• Reduction in oxidative stress (−47%); • Improvement in chlorophyll pigmentation (+85%).	[45]
	Zea mays	Salinity	R. intraradices, S. constrictum, Claroideoglomus etunicatum	At 100 mM NaCl, root colonization was: • 84.3% (R. intraradices); • 77.3% (C. etunicatum). indicating different responses depending on the AMF species	[10]
	Triticum durum	Drought	Indigenous 1AMF consortia	54% increase in root colonization with no-tillage practices compared to conventional tillage.	[46]
	Triticale hexaploide	Drought	Indigenous 1AMF consortia	With conservation tillage, increasing in the following: the abundance of vesicles (+6%) and arbuscules (+5%).	[47]
	Oryza sativa	Arsenic	R. irregularis	Phytoextraction: Increasing As accumulation in the following: • roots (+38%); • aerial parts (+55%).	[48]
	Vetiveria zizanioides	Copper	F. mosseae	Increase in the following: • height (+38%); • biomass (+32%). Reduction in Cu content in leaves (up to −111.2%).	[34]
Fabaceae	Glycine max	High-input systems + Drought	G. intraradices G. mosseae	No effect on biometric parameters. Increase in the following: • photosynthetic rate; • soil moisture content. Reduction in proline accumulation.	[31]
	Cicer arietinum	Salinity	R. fasciculatus	Increasing activity of antioxidant enzymes: • Superoxide Dismutase (+20–23%); • Catalase (+18%); • Peroxidase (+30%).	[49]
	Pongamia pinnata	Nickel	1AMF microbial consortium	Phytoremediation: High Ni removal efficiency (90–93%) from the substrate.	[50]
Solanaceae	Solanum lycopersicum	Salinity + High temperatures +42 °C	R. irregularis, C. etunicatum, C. claroideum, F. mosseae, F. geosporus	Reduction in the following: • flower drop; • Na accumulation (−25%). Increase in the following: • fruit set (+71%); • fresh weight (+30%); • Ca uptake (+20%); • Mg uptake (+15%). Improvement in CO2 assimilation (+ 40%).	[51]
Asteraceae	C. cardunculus var. scolymus	Drought	F. mosseae, R. irregulare	Increase in caffeoylquinic acids. Root colonization maintained under stress: 25%.	[39]
	C. cardunculus var. scolymus	Co-inoculum 1AMF + 2PGPR	Glomus spp + 2PGPR (Bacillus spp., Azotobacter spp.)	Increase in the following: • aerial biomass (+23%); • fresh weight yield (+54%).	[27]
Oleaceae	Olea europaea	Salinity	R. irregularis	Reduction in Na in leaves Increase in the following: • relative water content; • K+/Na+ ratio.	[48]
	Olea europaea	Co-inoculum 1AMF + 2PGPR	G. intraradices + 2PGPR	Improved uptake of the following: • N (+26%); • P (+60%); • Fe (+25%); • other nutrients.	[52]
Rosaceae	Fragaria ananassa	High temperatures 42 °C	F. mosseae	Increase in the following: • fruit weight (+11%); • yield (+6%); • photosynthetic efficiency (Fv/Fm); Reduction in membrane damage.	[53]
Apiaceae	Daucus carota	Low temperatures 15 °C	G. intraradices, G. claroideum, G. mosseae	Reduction in hyphal growth sporulation (60–70%), with G. intraradices being more tolerant to cold.	[30]
Cucurbitaceae	Cucumis sativus	Drought	Mix of 1AMF + 2PGPR (Bacillus, Pantoea, Pseudomonas)	Increase in the following: • yield (+34%); • water use efficiency.	[54]
Euphorbiaceae	Jatropha curcas	Nickel	1AMF microbial consortium	Ni removal efficiency from 82% to 86%.	[50]

¹AMF: arbuscolar mycorrhiza fungi. ²PGPR: plant growth-promoting rhizobacteria.

). AMF exert multifaceted effects under abiotic stress, including improved water and nutrient acquisition, enhanced osmotic adjustment, stabilization of cellular membranes, and activation of antioxidant systems. Their capacity to modulate ion transport and reduce the translocation of toxic ions further contributes to improved plant performance under Mediterranean conditions. A schematic representation of AMF-mediated responses to salinity stress is provided in Figure 3, highlighting the interplay between AMF colonization, stress-responsive genes, ion transporters, and antioxidant pathways [44].

3.1.1. Drought Stress

Drought remains one of the most severe constraints for agriculture in Mediterranean regions due to extended dry periods and irregular rainfall. AMF mitigate drought-induced damage by expanding the effective root-absorptive area through their extraradical hyphae, thereby improving water uptake and reducing osmotic stress [6,18]. Mycorrhizal plants often accumulate compatible solutes such as proline and trehalose, which help maintain cell turgor and protect macromolecular structures under dehydration [44]. Furthermore, AMF influence hormonal regulation—particularly abscisic acid—resulting in tighter stomatal control and improved water-use efficiency [29]. In Glycine max, AMF inoculation enhanced leaf photosynthetic rate under progressive drought, despite showing no significant changes in morphological traits under high-input agricultural systems [31]. Improvements in total polyphenols, sugars, and organic acids have also been recorded in mycorrhized plants [39,55], suggesting enhanced metabolic plasticity under water-limited conditions. In tomato, root colonization remained substantial (25% with Funneliformis mosseae and ~50% with Rhizophagus irregularis) even under drought stress [56], supporting the persistence of symbiosis despite unfavorable conditions. Globe artichoke (Cynara cardunculus var. scolymus) inoculated with AMF exhibited increased biomass production, improved yield stability, and enhanced accumulation of caffeoylquinic acids under drought [39]. Similarly, conservation agriculture practices have been shown to increase AMF colonization. In durum wheat, no-tillage increased root colonization by 54% compared with conventional tillage [46], while conservation tillage improved the efficacy of R. intraradices inoculation in triticale by increasing vesicle and arbuscule abundance by 6% and 5%, respectively [47]. In tomato, R. irregularis applied at transplanting increased plant height (+17%), leaf area (+15%), photosynthetic rate (+11%), chlorophyll content (+13%), stomatal conductance (+21%), yield (+24.8%), and tissue water content (+2.8%) relative to untreated controls. A consortium of G. mosseae and G. intraradices further increased plant height by 30.5% and chlorophyll content by 25% [57]. Collectively, these findings illustrate the strong potential of AMF to enhance drought tolerance across diverse Mediterranean crops.

3.1.2. Salinity Stress

Soil salinization is a widespread issue in semi-arid Mediterranean regions, leading to osmotic imbalance, ion toxicity, and oxidative stress [58]. AMF improve plant tolerance to salinity by modulating ion homeostasis, particularly through the reduction in Na⁺ accumulation and the enhancement of K⁺ and Ca²⁺ uptake—ions essential for enzymatic function and cellular stability [10,18]. Enhanced activities of antioxidant enzymes such as superoxide dismutase, catalase, and peroxidase further contribute to mitigating reactive oxygen species (ROS) damage (Figure 3) [44,58]. AMF may also indirectly reduce salinity effects by improving rhizosphere structure and decreasing salt accumulation around roots [18]. In tomato cultivars exposed to different salinity levels (1.4, 4.9, and 7.1 dS/m), inoculation with G. mosseae increased dry biomass by 22–31%, with even greater improvements observed in salt-sensitive varieties (up to 59%) under medium–high salinity [57]. In tomato plants inoculated with a mixture of R. irregularis, Claroideoglomus etunicatum, C. claroideum, F. mosseae, and F. geosporus, Ca and Mg uptake increased by 20% and 15%, respectively, while CO₂ assimilation improved by 40% under combined heat and salt stress; Na accumulation decreased by 25% [51]. In olive, AMF treatment with R. irregularis reduced Na accumulation in leaves and increased relative water content and the K⁺/Na⁺ ratio—key indicators of salinity tolerance [59]. In chickpea, R. fasciculatus reduced relative stress injury under salinity from 12.7% to 7.5% and increased antioxidant enzyme activity, superoxide dismutase (+20–23%), catalase (+18%), and peroxidase (+30%), under 4 dS m⁻¹ salinity [49]. Species-specific differences in AMF performance under salinity have also been reported. At 66 mM NaCl in maize, root colonization differed markedly among AMF species: 8.7% in R. intraradices, 62.7% in Septoglomus constrictum, and 65.3% in C. etunicatum. At 100 mM NaCl, colonization increased to 84.3%, 58.7%, and 77.3%, respectively, confirming species-dependent tolerance and efficiency [10].

3.1.3. Temperature Extremes

Temperature extremes—both heat waves and cold episodes—are increasingly frequent under Mediterranean climate change scenarios and represent major constraints for crop metabolism [6,7,60]. High temperatures promote oxidative stress, compromise photosynthesis, and disrupt membrane stability, while low temperatures impair enzymatic activity and reduce AMF development. AMF inoculation under combined heat and salinity stress has been shown to reduce flower drop, sustain CO₂ assimilation, and improve fruit set and yield compared with non-mycorrhizal plants [51]. In maize, native AMF (R. irregularis, F. mosseae, and Glomus spp.) reduced heat-induced oxidative stress by 47% and enhanced chlorophyll content by 85% [45]. In strawberry, inoculation with F. mosseae improved fruit weight (+11%), yield (+6%), and photosynthetic performance (higher Fv/Fm), while reducing membrane damage under heat stress [53]. Cold stress studies have also shown positive effects: AMF-associated maize exhibited improved sugar metabolism and more stable membrane composition under low temperatures [31,32]. However, AMF performance declines under sustained cold. In carrot root organ cultures, hyphal growth and sporulation of G. intraradices, G. claroideum, and G. mosseae decreased by 60–70% at 15 °C compared to optimal temperatures (25–30 °C), although G. intraradices remained relatively more tolerant [30]. AMF-mediated thermotolerance has been linked to enhanced heat-shock protein production and increased antioxidant activity [60,61].

3.1.4. Heavy Metal Stress

Heavy metal contamination is an emerging concern in Mediterranean agricultural soils, where metals such as arsenic, cadmium, copper, and nickel significantly impair plant growth by inducing oxidative stress and interfering with nutrient uptake [11,20,62]. AMF contribute to both phytostabilization and phytoextraction by immobilizing metals in their hyphae and spores, thus reducing translocation to shoots and alleviating toxicity [20,37]. Additionally, AMF improve soil organic matter stabilization, thereby reducing the bioavailability of heavy metals such as As and Cd [11,63]. High colonization levels by Rhizoglomus spp. have been observed in heavily contaminated sites, indicating their potential ecological resilience and utility in phytoremediation [64]. In rice, R. irregularis combined with Si increased As accumulation by 38% in roots and 55% in shoots, suggesting a synergistic role of AMF in metal translocation [48]. In Jatropha multifida grown on metal- and metalloid-contaminated landfill soil, AMF inoculation enhanced biomass production and increased shoot and root accumulation of several elements, confirming its potential for phytoremediation in degraded sites [50]. In Vetiveria zizanioides, AMF inoculation under Cu stress increased plant height by 38% and biomass by 32%, while reducing Cu content in leaves and roots compared with non-inoculated plants [34]. The combination of AMF with phosphorus management has been proposed to reduce metal uptake while maintaining growth [20,62].

3.2. Biotic Stress and Its Mitigation Through Arbuscular Mycorrhizal Fungi

Biotic stress encompasses plant damage caused by pathogenic fungi, bacteria, viruses, herbivorous insects, and parasitic nematodes, all of which contribute to significant yield losses by reducing plant vigor and increasing susceptibility to secondary infections [23,32,65,66]. AMF have emerged as promising biological tools to enhance plant resilience under these conditions [35,37,67]. Their protective effects are mediated through multiple pathways, including the priming of salicylic acid-dependent systemic acquired resistance (SAR), jasmonic acid-dependent induced resistance (IR), and long-term modulation of plant immune responses [36,68].

In addition to biochemical signaling, AMF influence plant resistance through competition for root colonization space, alteration of rhizosphere microbial communities, and improved host nutritional status [25,33]. These interactions lead to enhanced immune function, reduced pathogen incidence, and improved yield stability under biotic pressure (

Table 2. Effects of arbuscular mycorrhizal fungi on biotic stress in crops under Mediterranean climate.

Family	Species	Stress Agent	AMF	Effect Detail	Reference
Fabaceae	Phaseolus vulgaris	Rhizoctonia solani	Mix: Glomus mosseae, G. intraradices, G. clarum, G. gigantea, G. margarita	Reduction in disease incidence (from 100% to 73.3%) and severity (from 100% to 66.3%).	[72]
	Glycine max	Aulacorthum solani	Gigaspora margarita	Negative: The aphid was 10 times more abundant on inoculated plants.	[66]
	Glycine max	herbivorous insects	1AMF	No effect: 75% of interactions are neutral; Positive: 25% for interaction (reduced larval biomass).	[66]
	Glycine max	Meloidogyne incognita	Funneliformis mosseae	The following reductions: • 60% infection; • 27–32% egg hatching.	[32,73]
Solanaceae	Solanum lycopersicum	Alternaria solani, Botrytis cinerea Pratylenchus penetrans	Rhizophagus irregularis G. mosseae	Increase in resistance to foliar pathogens. Reduction of 87% in nematode population in root.	[67]
Poaceae	Oryza sativa	Magnaporthe oryzae, Lissorhoptrus oryzophilus	R. irregularis	Increase in resistance to the pathogen Magnaporthe oryzae and the insect Lissorhoptrus oryzophilus.	[35,37]
	Sorghum vulgare	Spodoptera frugiperda	G. intraradices, G. mosseae, G. aggregatum, G. monosporum	Significant reduction in insect incidence compared to the control.	[74]
Asteraceae	Cynara cardunculus var. scolymus	Verticillium dahliae	G. viscosum	Mitigation of infections	[71]
Plantaginaceae	Plantago lanceolata	Arctia caja	G. intraradices, G. claroideum, G. mosseae	Larvae of Arctia caja consumed 77–82% less plant material from non-mycorrhizal plants.	[65]
Rubiaceae	Coffea arabica	Meloidogyne	Indigenous 1AMF consortia	Average reduction in infection severity of 38.3–52.5%.	[35]
Musaceae	Musa paradisiaca	R. similis and P. coffeae	G. intraradices	Reduction in nematode population by 72% (R. similis) and 84% (P. coffeae).	[69]
Poaceae	Grasses	Pratylenchus	Glomerales, Glomus, Funneliformis	Meta-analysis: • decrease in 36.6% of cases; • no effect in 46.6% of cases; • increase in 16.6% of cases.	[70]

¹AMF: arbuscolar mycorrhiza fungi.

) [25,69,70,71]. A conceptual overview of AMF-mediated defense mechanisms against major biotic stressors is provided in Figure 4 [37].

3.2.1. Pathogen Resistance

AMF symbiosis is widely recognized for enhancing plant resistance to soilborne pathogens such as Rhizoctonia solani, Fusarium oxysporum, and Phytophthora spp., which compromise root integrity and substantially reduce crop productivity [20,35,37]. Mycorrhizal colonization stimulates the production of defense-related phytoalexins and pathogenesis-related proteins and upregulates critical genes in host defense pathways [32,67], ultimately resulting in decreased disease incidence and severity [67,73]. AMF also reshape root exudation profiles, enriching the rhizosphere with microbial communities antagonistic to pathogens [8,13]. Beyond root pathogens, AMF reduce foliar disease susceptibility. Enhanced resistance to Magnaporthe oryzae in rice and to Alternaria solani and Botrytis cinerea in tomato has been documented in AMF-colonized plants [32,35]. In common bean, a mixed AMF inoculum (G. mosseae, G. intraradices, G. clarum, G. gigantea, and G. margarita) reduced R. solani incidence from 100% to 73.3% and disease severity from 100% to 66.3% after one week [72]. In globe artichoke, AMF mitigated infections caused by Verticillium dahliae, confirming their role as effective bioprotection agents in Mediterranean horticultural systems [71]. Although mostly beneficial, AMF-induced immune modulation can involve trade-offs: in certain cases, pathogens may exploit AMF-modified signaling states, potentially suppressing specific defenses [68]. Understanding these context-dependent outcomes is therefore essential for optimizing AMF-based disease management strategies.

3.2.2. Insect Herbivory Resistance

Herbivorous insects cause direct tissue damage, reduce photosynthetic area, and may facilitate subsequent pathogen infections. AMF enhance plant defense against herbivores primarily by stimulating the biosynthesis of secondary metabolites—such as flavonoids, terpenoids, and phenolic compounds—that function as deterrents or toxins [23,65]. AMF-induced resistance substantially affects herbivore feeding behavior. For example, larvae of Arctia caja consumed 77–82% less plant material from mycorrhizal Plantago lanceolata compared to non-mycorrhizal plants, depending on the AMF species involved [65,66]. In sorghum, AMF inoculation reduced the incidence of Spodoptera frugiperda attacks compared to controls [74]. Similarly, AMF enhanced plant resistance against Lissorhoptrus oryzophilus in rice [15,75]. However, herbivory responses are not uniformly positive. A comprehensive synthesis indicated that interactions with generalist chewing herbivores were neutral in 75% of cases and negative (reduced larval biomass) in 25%. For specialist herbivores, 83% of interactions were neutral and 17% positive. Notably, populations of Aulacorthum solani were tenfold higher on Glycine max plants inoculated with Gigaspora margarita [66]. These findings highlight the context-dependency of AMF–insect interactions and suggest that AMF may either reduce or, in some cases, inadvertently increase herbivore performance depending on the insect and AMF species involved.

3.2.3. Nematode Suppression

Root-knot nematodes (Meloidogyne spp.) and lesion nematodes (Pratylenchus spp.) are among the most devastating pests in Mediterranean cropping systems, causing severe root dysfunction and yield losses. AMF mitigate nematode attacks through multiple mechanisms, including the following:

(i) Strengthening of physical barriers via increased lignin and callose deposition, which impede nematode penetration [73];

(ii) Modification of root exudates, reducing nematode attraction and host recognition [70,73];

(iii) Improved plant nutritional status, supporting enhanced tolerance and post-infection recovery [15,59].

In tomato and soybean, F. mosseae reduced Meloidogyne incognita infection by 60% and decreased egg hatchability by 27–32% in early infection stages [25,37]. In coffee, AMF reduced root-knot nematode infection by 38.3–52.5% across multiple studies [35]. For Pratylenchus penetrans, AMF colonization dramatically reduced nematode populations: G. mosseae lowered root nematode densities by 87%, egg production by 45%, and reproductive female numbers by 34%, resulting in a 51% reduction in second-stage juveniles [76]. In banana, colonization by G. intraradices reduced Radopholus similis populations by 72% and Pratylenchus coffeae by 84% [69]. A meta-analysis of 60 case studies showed that AMF reduced Pratylenchus densities in 36.6% of cases, had no effect in 46.6%, and increased populations in 16.6% of observations, highlighting species-dependent and colonization-level-dependent responses [70]. Overall, AMF demonstrate strong potential for nematode management in Mediterranean systems, although efficacy varies depending on both AMF species and nematode feeding strategies.

4. Co-Inoculation of AMF and Biostimulants

The integration of AMF into sustainable agricultural strategies represents a promising approach to mitigating abiotic and biotic stresses while reducing reliance on chemical inputs. Co-inoculation with other beneficial microorganisms—particularly plant growth-promoting rhizobacteria (PGPR) and beneficial fungi such as Trichoderma spp.—is increasingly recognized for its capacity to amplify AMF-driven benefits and enhance overall plant resilience [24,25,77]. In cucumber, Bicer [54] demonstrated that combined AMF and PGPR inoculation (Bacillus megaterium, Pantoea agglomerans, Pseudomonas fluorescens) significantly increased yield by 34% under severe water deficit (33% of field capacity). Co-inoculated plants also exhibited superior water-use efficiency, with the greatest improvements observed under reduced irrigation [54]. In globe artichoke, co-application of AMF (Glomus spp.) and PGPR (Bacillus spp., Azotobacter spp.) enhanced aboveground biomass by an average of 23% and increased fresh head yield by 54%, with cultivar-specific improvements ranging from 41% to 60% [27]. In olive, co-inoculation with G. intraradices and PGPR (B. megaterium, Burkholderia cedrus, and Streptomyces beta-vulgaris) induced significant shifts in the rhizosphere microbial community and increased the uptake of essential macro- and micronutrients, including N (+26%), P (+60%), Fe (+25%), Mn (+18%), Zn (+26%), B (+22%), and Cu (+14%), as well as the accumulation of phenolic compounds such as verbascoside [52]. Similarly, reducing mineral fertilization (NPK) by 50–70% combined with mixed AMF–PGPR inocula (G. mosseae, G. fasciculatum) improved growth and nutritional status in olive seedlings [78]. Overall, AMF–PGPR consortia strengthen agroecosystem resilience, reduce chemical input dependency, and promote long-term soil health, representing a key mechanism for advancing sustainable agriculture under Mediterranean climate conditions [79,80].

5. Limitations and Challenges

Despite extensive evidence of AMF benefits, their practical implementation in agriculture remains limited by biological, agronomic, and methodological constraints. AMF performance is highly context-dependent. Plant stress tolerance and pathogen resistance vary significantly depending on the specific combination of plant genotype and AMF species or isolate [25,73,81]. Certain AMF may even exacerbate pest pressures; for instance, Gigaspora spp. have been associated with increased Pratylenchus populations [73,81]. Low AMF colonization can also lead to increased nematode density [76], and in some host–herbivore systems, AMF have been reported to increase insect attractiveness [70,73]. Agricultural practices can severely influence AMF colonization. High phosphorus fertilization may reduce AMF colonization and functionality [1], and intensive tillage can negatively impact AMF abundance, diversity, and ecosystem functionality [47]. Fungicides may also impair the symbiosis and reduce AMF effectiveness [72]. Furthermore, exotic or commercial AMF strains often fail to outperform native communities, highlighting the importance of using locally adapted isolates [63,82]. In extreme environments such as metal-contaminated soils, AMF may grow exclusively intraradically to avoid direct exposure to toxic elements, limiting their functional interactions in the rhizosphere [34,64]. Methodological limitations also reduce reproducibility and translation to field conditions. Most studies rely on pot experiments that show limited ecological realism and do not necessarily reflect open-field multifactorial dynamics [73,81]. Furthermore, research is frequently based on outcome-only approaches, while mechanistic understanding remains insufficient, highlighting the need to adopt direct and molecular process-oriented methodologies [32,81]. Practical challenges also concern the quality of commercially available inocula, which may have low AMF viability, a risk of contamination, and occasionally induce negative microbial effects on crops [83]. In addition, currently adopted AMF quantification approaches, including microscopy-based assessments, are time-consuming and subjective [79,84]. Overall, despite the recognized beneficial potential of AMF, their agronomic implementation remains largely constrained by inconsistent symbiotic performance, context dependency, lack of inoculum standardization, and limited field validation. Future work must integrate ecological criteria for strain selection, rigorous evaluation under realistic stress combinations, and improved inoculum quality control to enable reliable, scalable adoption of AMF within sustainable agricultural systems, particularly under Mediterranean environments.

6. Future Technological Perspectives and Emerging Research Directions

Bridging the gap between laboratory findings and field performance is essential for the widespread adoption of AMF-based technologies [73,81]. Future research should prioritize mechanistic understanding of AMF–plant interactions, including signaling pathways governing Mycorrhiza-Induced Resistance (MIR), with particular attention to nematode defense mechanisms [22,32]. Large-scale, ecologically realistic trials are required to validate scalability under multifactorial stress conditions [63,85]. Optimizing inoculum dosage and timing [63] and selecting plant genotypes that show stable AMF responsiveness across environments [45] will be critical. Locally adapted isolates should be prioritized for improved performance under region-specific constraints, such as salinity [10,82]. Future research should also explore multi-component inoculants integrating AMF with native microbial communities, such as PGPR and endophytes, to enhance phytoremediation and biocontrol outcomes [24,63,78,79], and consider advanced delivery strategies including nanotechnology combined with RNA interference to achieve highly specific pest suppression [86]. In this sustainable framework, the co-addition of nanotechnologies and biofertilizers provides a strategy to significantly increase the net income of growers, especially under moderate drought stress conditions [27] (

Table 3. Emerging technological approaches integrating AMF in different crop species.

Species	Technology Applied	Effect Detail	Reference
Cynara cardunculus var. scolymus	In vitro micropropagation combined with 1AMF inoculation	Increased phenolic compound accumulation	[39]
C. cardunculus var. scolymus	Co-inoculation 1AMF + 2PGPR	Increased aerial biomass and head yield; improved functional quality traits	[27]
Olea europaea	1AMF inoculation combined with 2PGPR consortia (field trial)	Increased macro- and micronutrient uptake and enhanced secondary metabolite accumulation (oleuropein; verbascoside)	[52]
Triticum aestivum	Native 1AMF isolates for phytoremediation	Improved biomass and photosynthetic efficiency in heavy-metal contaminated soils	[63]
Zea mays	Native 1AMF isolated from saline Mediterranean soils	Enhanced antioxidant systems and higher salinity tolerance	[10]
Glycine max	Nanotechnology + RNA interference delivery	Highly specific suppression of plant-parasitic nematodes	[17]
Salvia officinalis	Co-application of TiO2 nanoparticles + 1AMF	Increased essential oil quantity and improved quality under drought stress	[75]

¹AMF: arbuscolar mycorrhiza fungi. ²PGPR: plant growth-promoting rhizobacteria.

). The influence of microbial inoculation on the qualitative traits of agricultural products, including phenolic composition, warrants further attention, also in relation to AMF use under Mediterranean conditions [10,27,49]. The application of AMF in Mediterranean agroecosystems could provide significant economic benefits in both the short and long term by improving the cost efficiency of agricultural production systems [87,88]. Beyond reducing input costs, particularly those associated with mineral fertilizers, AMF application contributes to enhanced crop yield and quality, thereby directly increasing farm profitability, though their scalability is still limited by inoculum cost and availability [89].

7. Final Remarks

Mediterranean-type climates are characterized by pronounced seasonal water scarcity, elevated evapotranspiration rates, irregular precipitation patterns, thermal extremes, and progressive soil degradation. These interacting stressors continue to pose substantial challenges to crop productivity and agroecosystem stability. By synthesizing evidence across diverse host species, environmental stressors, AMF taxa, and systematically mapping the “native microbiome” to avoid the risks of competition with alien species and co-inoculation strategies, this review highlights the strategic importance of incorporating mycorrhizal technologies into sustainable crop management frameworks tailored to Mediterranean agro-climatic conditions and other semi-arid or arid regions with similar stressors. AMF have emerged as pivotal biological partners capable of supporting plants under both abiotic and biotic stress. The literature reviewed herein demonstrates that AMF contribute to enhanced drought tolerance, reduced ion toxicity under salinity, improved thermotolerance through photosynthetic stabilization, and modulation of plant immune pathways, resulting in strengthened resistance against pathogens, herbivores, and nematodes. Their synergistic interactions with plant growth-promoting rhizobacteria further reinforce their value for resource-use efficiency and long-term soil health. However, most studies to date have explored AMF benefits in isolation, focusing on single stress factors under controlled conditions. Mediterranean agricultural systems, by contrast, are inherently exposed to multiple, simultaneous stressors. There remains an urgent need for integrative, ecologically realistic research that evaluates AMF performance under combined drought–salinity–heat–pathogen scenarios, as well as field-based investigations capable of capturing the complexity of Mediterranean environments. As climate extremes intensify and water resources become increasingly limited, the strategic use of AMF—alone or in combination with other beneficial microorganisms—offers a promising nature-based solution to enhance crop resilience, stabilize yields, and promote agroecosystem sustainability. Advancing this approach will require coordinated efforts to optimize inoculum selection, refine agronomic practices that support AMF functionality, and expand mechanistic understanding of AMF-mediated stress mitigation. Such evidence-based integration is essential for developing robust, climate-resilient Mediterranean cropping systems capable of sustaining food production under future environmental constraints.