Arbuscular Mycorrhizal Fungi Treatments Research Articles

Effects of Claroideoglomus etunicatum Fungus on the Growth Parameters of Maize (Zea mays L.) Plants under Boron Toxicity and Salt Stress

Soil salinity is an emerging phenomenon threatening arid and semiarid areas due to changing climatic events. Salinity, in combination with other elemental contaminants, can often harm crop performance and productivity. This experiment was conducted to evaluate the mitigating effect of Claroideoglomus etunicatum, an arbuscular mycorrhizal fungus (AMF), on combined boron (B) toxicity and salt stress symptoms in maize plants. After the stress and AMF treatments, plants were subjected to a wide range of analyses, such as AMF colonization rates, ion leakage, plant biomass, and concentration of B, phosphorus, sodium, potassium, iron, zinc, copper, and manganese in root and shoot tissues. The results showed that the combined stress did not affect the AMF colonization rate. AMF inoculation significantly increased plant biomass, the K+/Na+ ratio, and shoot B, sodium, and copper concentrations, but reduced root B concentrations and ion leakage. AMF inoculation slightly increased root dry weight and the sodium, potassium, zinc, copper and Mn contents in shoots under combined B and salinity stress, while AMF reduced the electrolyte leakage in leaves. It is inferred that AMF can ameliorate B toxicity in maize by improving biomass and reducing B concentration in plant tissues. Our research implies that C. etunicatum could be a valuable candidate for assisting in the remediation of boron-contaminated and saline soils.

Plant-Growth-Promoting Rhizobacteria and Arbuscular Mycorrhizal Fungi May Improve Soil Fertility and the Growth, Nutrient Uptake, and Physiological Performance of Batavia Lettuce (Lactuca sativa L. var. longifolia) Plants

A greenhouse experiment was realized to investigate the effects of plant-growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on soil quality and the growth, nutrient uptake, and physiological performance of Batavia lettuce (Lactuca sativa L. var. longifolia). For this purpose, six fertilization treatments were applied: (i) inorganic fertilization (I.F.—control, i.e., usual/conventional fertilization), (ii) I.F. + PGPR, (iii) I.F. + PGPR + AMF, (iv) manure (MAN), (v) MAN + PGPR, and (vi) MAN + PGPR + AMF. Soil fertility was influenced by the treatments, and soil respiration (CO2 flux) was significantly increased after applications of PGPR and AMF. Following MAN fertilization in particular, an approximately sixfold higher soil respiration value was recorded following the MAN + PGPR + AMF treatment compared to the control (I.F.). Root, leaf, and total biomass dry weights were significantly affected by the PGPR and AMF applications, mainly following the I.F. treatment. In contrast, K, Mg, and Fe uptake was significantly influenced by PGPR and AMF application following the MAN treatment. The SPAD value, performance index (PI), photosynthetic rate, and stomatal conductance were significantly higher in the I.F. + PGPR + AMF-treated plants compared to the control plants. Overall, these data prove the beneficial roles of PGPR and AMF in soil quality and fertility and the nutrient uptake and physiological performance of lettuce plants. However, further clarification is needed in the near future to test the interaction effects between PGPR, AMF, and the type of fertilizer used (organic or inorganic).

Effect of arbuscular mycorrhizal symbiosis on growth and biochemical characteristics of Chinese fir (Cunninghamia lanceolata) seedlings under low phosphorus environment.

The continuous establishment of Chinese fir (Cunninghamia lanceolata) plantations across multiple generations has led to the limited impact of soil phosphorus (P) on tree growth. This challenge poses a significant obstacle in maintaining the sustainable management of Chinese fir. To investigate the effects of Arbuscular mycorrhizal fungi (AMF) on the growth and physiological characteristics of Chinese fir under different P supply treatments. We conducted an indoor pot simulation experiment in the greenhouse of the Forestry College of Fujian Agriculture and Forestry University with one-and-half-year-old seedlings of Chinese fir from March 2019 to June 2019, with the two P level treatment groups included a normal P supply treatment (1.0 mmolL-1 KH2PO4, P1) and a no P supply treatment (0 mmolL-1 KH2PO4, P0). P0 and P1 were inoculated with Funneliformis mosseae (F.m) or Rhizophagus intraradices (R.i) or not inoculated with AMF treatment. The AMF colonization rate in the root system, seedling height (SH), root collar diameter (RCD) growth, chlorophyll (Chl) photosynthetic characteristics, enzyme activities, and endogenous hormone contents of Chinese fir were estimated. The results showed that the colonization rate of F.m in the roots of Chinese fir seedlings was the highest at P0, up to 85.14%, which was 1.66 times that of P1. Under P0 and P1 treatment, root inoculation with either F.m or R.i promoted SH growth, the SH of R.i treatment was 1.38 times and 1.05 times that of F.m treatment, respectively. In the P1 treatment, root inoculation with either F.m or R.i inhibited RCD growth. R.i inhibited RCD growth more aggressively than F.m. In the P0 treatment, root inoculation with F.m and R.i reduced the inhibitory effect of phosphorus deficiency on RCD. At this time, there was no significant difference in RCD between F.m, R.i and CK treatments (p < 0.05). AMF inoculation increased Fm, Fv, Fv/Fm, and Fv/Fo during the chlorophyll fluorescence response in the tested Chinese fir seedlings. Under the two phosphorus supply levels, the trend of Fv and Fm of Chinese fir seedlings in different treatment groups was F.m > R.i > CK. Under P0 treatment, The values of Fv were 235.86, 221.86 and 147.71, respectively. The values of Fm were 287.57, 275.71 and 201.57, respectively. It increased the antioxidant enzyme activity and reduced the leaf's malondialdehyde (MDA) content to a certain extent. It is concluded that AMF can enhance the photosynthetic capacity of the host, regulate the distribution of endogenous hormones in plants, and promote plant growth by increasing the activity of antioxidant enzymes. When the P supply is insufficient, AMF is more helpful to plants, and R.i is more effective than F.m in alleviating P starvation stress in Chinese fir.

Improving vanadium removal from contaminated river water in constructed wetlands: The role of arbuscular mycorrhizal fungi

Industrial activities pose a significant ecological risk to water resources as they pollute surrounding waters with vanadium (V). Although the contribution of plants and substrates to V removal in constructed wetlands (CWs) has been reported, the role of arbuscular mycorrhizal fungi (AMF) is unclear. The aim of the present study was to investigate the role of AMF in V removal in CWs and to elucidate the underlying mechanisms. Reed plants (Phragmites australis) were inoculated with an AMF strain (Rhizophagus irregularis) in CW columns, creating AMF-inoculated (+AMF) and non-inoculated (-AMF) treatments. Three levels of influent V concentrations (low: 0.50 mg L−1, medium: 1.14 mg L−1 and high: 1.52 mg L−1) were examined. The + AMF treatment showed higher V removal (60%–98%) than the control (40%–82%) in all three conditions, although the difference was not significant in some cases. The mean mycorrhizal effects were 75%, 19%, and 28% for low, moderate, and high influent V concentrations, respectively. The +AMF treatment showed a higher GRSP-bonded V concentration (5.5 mg g−1) than the -AMF treatment (4.0 mg g−1). Furthermore, +AMF treatment showed larger plants with higher V concentrations in their tissues, accompanied by increased biological concentration factors and biological accumulation factors. Given the remarkable positive effect of AMF on V removal, our study suggests that treating AMF in CWs is a worthwhile approach.

Improvement of Panax notoginseng saponin accumulation triggered by methyl jasmonate under arbuscular mycorrhizal fungi.

Panax notoginseng is a highly valued perennial medicinal herb plant in Yunnan Province, China, and the taproots are the main medicinal parts that are rich in active substances of P. notoginseng saponins. The main purpose of this study is to uncover the physiological and molecular mechanism of Panax notoginseng saponin accumulation triggered by methyl jasmonate (MeJA) under arbuscular mycorrhizal fungi (AMF) by determining physiological indices, high-throughput sequencing and correlation analysis. Physiological results showed that the biomass and saponin contents of P. notoginseng, the concentrations of jasmonic acids (JAs) and the key enzyme activities involved in notoginsenoside biosynthesis significantly increased under AMF or MeJA, but the interactive treatment of AMF and MeJA weakened the effect of AMF, suggesting that a high concentration of endogenous JA have inhibitory effect. Transcriptome sequencing results indicated that differential expressed genes (DEGs) involved in notoginsenoside and JA biosynthesis were significantly enriched in response to AMF induction, e.g., upregulated genes of diphosphocytidyl-2-C-methyl-d-erythritol kinases (ISPEs), cytochrome P450 monooxygenases (CYP450s)_and glycosyltransferases (GTs), while treatments AMF-MeJA and salicylhydroxamic acid (SHAM) decreased the abundance of these DEGs. Interestingly, a high correlation presented between any two of saponin contents, key enzyme activities and expression levels of DEGs. Taken together, the inoculation of AMF can improve the growth and saponin accumulation of P. notoginseng by strengthening the activities of key enzymes and the expression levels of encoding genes, in which the JA regulatory pathway is a key link. This study provides references for implementing ecological planting of P. notoginseng, improving saponin accumulation and illustrating the biosynthesis mechanism.

Effects of biofertilizer on the production of bell pepper (Capsicum annuum L.) in greenhouse

Biological fertilizers are useful sources of plant nutrients that enhance crop growth and quality, produce plant hormones, and contribute to sustainable crop production by maintaining soil fertility. The effect of arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (PGPRs) applications in greenhouses on bell pepper (Capsicum annuum L. Nervin) has been studied by conducting a split plot experiment in three replications using a randomized complete block design. The biofertilizers included AMF inoculations (Rhizophagus irregularis + Funneliformis mosseae), and three different bacterial inoculations (Azotobacter chroococcum + Azospirillum lipoferum; Enterobacter cloacae + Pseudomonas putida; Bacillus subtilis + Bacillus amyloliquefaciens) and non-inoculation as a control with two levels of organic fertilizers (with and without).The organic treatment fertilizer, in combination with the inoculation of E. cloacae + P. putida or A. chroococcum + A. lipoferum, as well as AMF, significantly increased the microbial population within the rhizosphere compared to the control. In all treatments, fruit yield increased, with the highest value (15.94 kg m−2) recorded in the AMF treatment, indicating an increase of 18% over the control. All inoculations significantly increased total phenol and ascorbic acid levels in fruit when organic fertilizer was applied. The most significant N uptake was observed in A. crococcum + A. lipoform inoculation, while the most significant Fe uptake was observed in AMF. It was found that all inoculations significantly increased P, K, and Zn uptake. In conclusion, A combination of organic fertilizer and mycorrhizal or (Azotobacter chroococcum + Azospirillum lipoferum) inoculations increased the productivity and quality of bell peppers grown in greenhouses.

Effects of the synergistic treatments of arbuscular mycorrhizal fungi and trehalose on adaptability to salt stress in tomato seedlings.

AMF improve the plant adaptability to salt resistance by increasing mineral absorption and reducing the damage of saline soil. Trehalose plays an important role in plant response to salt damage by regulating osmotic pressure. Together, the use of AMF and trehalose in tomato seedlings proved efficient in regulating host substance synthesis, osmosis, and antioxidant enzymes. These synergistic effects significantly improved seedling adaptability to salt stress by enhancing cell osmotic protection and cell antioxidant capacity, ultimately reducing losses to crops grown on land where salinization has occurred.

Effect of Concentration of Liquid Organic Fertilizer and Arbuscular Mycorrhizal Fungi (CMA) on Growth and Red Bean Plant (Phaseolus vulgaris L)

This study aims to determine the interaction between the effect of liquid organic fertilizer concentration and arbuscular mycorrhizal fungi (CMA) on the growth and yield of red bean plants (Phaseolus vulgaris L.). The experiment was conducted in Nusaherang Village, Nusaherang District, Kuningan Regency, from July to September 2022. The research method used is the experimental method of Group Random Design (RAK) factorial pattern. The treatment consists of two factors and is repeated three times. The first factor is the concentration of liquid organic fertilizer (P), which consists of three levels, namely: P1 (5 ml / l), P2 (10 ml / l), and P3 (15 ml / l). The second factor of arbuscular mycorrhizal fungi (C) consists of three levels, namely: C1 (5 g / plant), C2 (10 g / plant), and C3 (15 g / plant). The primary observation data is processed using variance analysis; if there is a noticeable effect, the test is continued with the Duncan multiple distance test. The results showed a real interaction between the concentration of liquid organic fertilizer and arbuscular mycorrhizal fungi on plant height aged 21 HST, root length aged 21 HST, number of flowers aged 35 HST, and number of pods per red bean plant. The concentration treatment of liquid organic fertilizer has an independent effect on the number of leaves aged 21 HST. In comparison, the treatment of arbuscular mycorrhizal fungi has an independent effect on the number of leaves aged 21 and 28 HST and the number of seeds per pod. The treatment of liquid organic fertilizer and arbuscular mycorrhizal fungi has the same effect on yield variables, so the average weight of fresh red bean beans per plot is 626 g (0.63 kg) or equivalent to 1.6 tons/ha, assuming 80% of the land is effective.

Effect of inoculation with arbuscular mycorrhizal fungi on the energy metabolism of selenite-rich amaranth.

A series of pot trials were undertaken to examine the impact of four arbuscular mycorrhizal fungi (AMF), namely Glomus mosseae (G.m), Glomus etunicatum (G.e), Corymbiglomus tortuosum (C.t), and the combined application of Glomus etunicatum and Corymbiglomus tortuosum (G.e + C.t), on the energy metabolism of amaranth plants grown in soil enriched with selenite at a concentration of 0.5 mg kg-1 . The inoculation of four AMFs resulted in an increase in both amaranth biomass and selenium (Se) content in leaves. The activities of phosphoglucose isomerase (PGI) and glucose-6-phosphate dehydrogenase + 6-phosphogluconate dehydrogenase were observed to decrease when AMFs were inoculated, as compared with the absence of AMF inoculation. The inoculation with G.m, C.t, and G.e + C.t resulted in an increase in succinate dehydrogenase activity; however, the inoculation with G.m, G.e, and G.e + C.t led to an increase in ascorbate oxidase activity. Furthermore, the inoculation of all four AMFs resulted in an increase in cytochrome c oxidase activity and the concentrations of oxidized coenzyme I (NAD) and reduced coenzyme I (NADH). The polyphenol oxidase activity of amaranth plants increased when inoculated with G.m and G.e, whereas it decreased when inoculated with C.t and G.e + C.t. Furthermore, the application of all four AMF treatments resulted in a reduction in adenosine triphosphate (ATP) levels and energy charge. It was worth mentioning that there was a clear inverse relationship between the energy charge and the biomass, Se concentration in the leaves. The findings presented in this research indicated that AMF may have an impact on energy metabolism and ultimately the biomass of amaranth by influencing the uptake of Se.

Physiological response and phytoremediation potential of dioecious Hippophae rhamnoides inoculated with arbuscular mycorrhizal fungi to Pb and Zn pollution.

Plant-microorganism combined remediation of heavy metal pollution has been reported, but little attention has been paid to the effect of arbuscular mycorrhizal (AM) fungi on phytoremediation of dioecious plants under heavy metal pollution. In this study, the growth, physiological responses and phytoremediation traits of Hippophae rhamnoides were determined to evaluate whether sex-specific ecophysiological responses and phytoremediation capacities of females and males are affected by additional AM fungi (Glomus mosseae) under heavy metal treatments. The results showed that excess Pb and Zn stresses inhibited photosynthetic capacities of both sexes. However, inoculated AM fungi treatment increased the activity of photosynthesis, content of photosynthetic pigment, activity of superoxide dismutase, the content of proline and root Pb content and enrichment coefficient of males while decreased root Pb content of females under Pb stress. On the other hand, inoculated AM fungi treatment increased the photosynthetic activities and Pro accumulation of females, and activity of superoxide dismutase and transport coefficient of males under Zn stress. These results demonstrate that H. rhamnoides inoculated AM fungi showed significant sex-specific responses on the growth, physiological traits and phytoremediation potential to Pb and Zn stress. AM fungi significantly improved the tolerance of males to Pb stress and both sexes to Zn stress, which indicates H. rhamnoides and AM fungi can be used as a plant-microbial combined remediation method for Pb and Zn contaminated soil. More attention should be paid on sexual-specific responses and phytoremediation of dioecious plants to heavy metals in the future.

Arbuscular mycorrhizal fungi increased peanut (Arachis hypogaea L.) yield by changing the rhizosphere microbial community structure in saline-alkali soil.

Arbuscular mycorrhizal fungi (AMF) have demonstrated the potential to enhance the saline-alkali tolerance in plants. Nevertheless, the extent to which AMF can ameliorate the tolerance of salt-sensitive plants to alkaline conditions necessitates further investigation. The current study is primarily centered on elucidating the impact of AMF on the growth of the Huayu22 (H22) when cultivated in saline-alkaline soil. We leveraged DNA of rhizosphere microorganisms extracted from saline-alkali soil subjected to AMF treatment and conducted high-throughput sequencing encompassing 16S rRNA gene and ITS sequencing. Our findings from high-throughput sequencing unveiled Proteobacteria and Bacillus as the prevailing phylum and genus within the bacterial population, respectively. Likewise, the predominant fungal phylum and genus were identified as Ascomycota and Haematonectria. It is noteworthy that the relative abundance of Proteobacteria, Actinobacteria, Chloroflexi, Bacteroidetes, and Ascomycota exhibited significant increments subsequent to AMF inoculation. Our investigation into soil enzyme activity revealed a remarkable surge post-AMF inoculation. Notably, the amounts of pathogen growth inhibitory enzymes and organic carbon degrading enzymes rise, as predicted by the putative roles of microbial communities. In saline-alkali soil, inoculation of AMF did boost the yield of H22. Notable improvements were observed in the weight of both 100 fruits and 100 grains, which increased by 20.02% and 22.30%, respectively. Conclusively, this study not only provides a theoretical framework but also furnishes empirical evidence supporting the utilization of AMF as a viable strategy for augmenting the yield of salt-sensitive plants grown in alkaline conditions.

Causal Analysis Between Rice Growth and Cadmium Accumulation and Transfer under Arbuscular Mycorrhizal Inoculation

Cadmium (Cd) contamination in rice has been a serious threat to human health. To investigate the effects of arbuscular mycorrhizal fungi (AMF) on the Cd translocation in rice, a controlled pot experiment was conducted. The results indicated that AMF significantly increased rice biomass, with an increase of up to 40.0%, particularly in root biomass by up to 68.4%. Notably, the number of prominent rice individuals also increased, and their plasticity was enhanced following AMF inoculation. AMF led to an increase in the net photosynthetic rate and antioxidant enzyme activity of rice. In the AMF treatment group, the Cd concentration in the rice roots was significantly higher (19.1%‒68.0%) compared with that in the control group. Conversely, the Cd concentration in the rice seeds was lower in the AMF treatment group, indicating that AMF facilitated the sequestration of Cd in rice roots and reduced Cd accumulation in the seeds. Path coefficients varied across different treatments, suggesting that AMF inoculation reduced the direct impact of soil Cd concentration on the total Cd accumulation in seeds. The translocation of Cd was consistently associated with simultaneous growth dilution and compensatory accumulation as a result of mycorrhizal effects. Our study quantitatively analyzed this process through path analysis and clarified the causal relationship between rice growth and Cd transfer under the influence of AMF.

Characterization of Lavender Essential Oil and Its Chemical Composition Intercropped with Marigold as Affected by Polyamines and Arbuscular Mycorrhizal Fungi Inoculation

ABSTRACT This study aimed to characterize the yield and biochemical response of lavender to polyamines (PAs) and arbuscular mycorrhizal fungi (AMF) inoculation under intercropping with marigold. The application of both putrescine (Put) and spermidine (Spd) was found to be effective even at low doses (500 mg/L), with Spd at a dose of 1500 mg/L (Spd3M1) being the most effective in promoting flowering and essential oil (EO) content. However, the highest values of flower yield, EO content, and EO yield were recorded when the plants inoculated with AMF were sprayed with PAs. Chemical compounds analyzed by the GC-MS technique revealed the presence of 40 individual compounds accounting for more than 98.91% of them. We observed a positive response (increase) in the content of linalool, limonene, and geraniol for PAs application and fungal inoculation. The highest increase in these compounds was recorded in 1500 mg/L Put or Spd with AMF treatments.

Effects of Arbuscular Mycorrhizal Fungi on Growth and Nutrient Accumulation of Oat under Drought Conditions

Arbuscular mycorrhizal fungi (AMF) have established themselves as pivotal allies in the realm of plant physiology, renowned for their remarkable contributions to augmenting both growth and resilience against environmental stresses. In this study, we embarked on a comprehensive investigation into the discernible impact of two distinct AMF species on a widely planted oat cultivar, ‘Qingyan No. 1’, when subjected to the austere conditions of a drought. The experimental design included three distinct AMF treatments (inoculation with Rhiaophagus intraradices, Funneliformis mosseae, or not), and the three water treatments were 75% of field capacity (well watered), 50% of field capacity (moderate drought), and 30% of field capacity (severe drought). The obtained results showed that the rate of inoculation under 75% FC for both AMF species was over 74%. Drought stress limited the growth and osmotic regulation of the oat plants. However, AMF inoculation observably increased the above-ground biomass under 75% FC and increased the root biomass under 30% FC. AMF inoculation also increased the root traits under 75% FC and 50% FC. R. intraradices inoculation increased the above-ground soluble sugar and soluble protein concentrations, and both AMF species showed decreased malondialdehyde (MDA) concentrations in the roots. Furthermore, the pervasive influence of drought stress exerted a discernible stranglehold on nutrient uptake in the oat plants, profoundly impacting the distribution of nutrients within the shoots and roots. Regardless of the drought stress treatment, the inoculation with both AMF species increased the P concentrations in the roots and the K and Mg concentrations in the roots, and the inoculation with R. intraradices increased the Ca concentration in the whole oat plant. Under 75% FC, the N concentration of the whole oat plant was significantly reduced by both AMF species. However, under 50% FC and 30% FC, the N concentrations in the shoots inoculated with both AMF species were close to that of the non-inoculated shoots. In summary, AMF improved the osmotic regulation and nutrient absorption and distribution of oat plants under drought stress and thus promoted the growth and biomass accumulation of oat plants.

Arbuscular mycorrhizal fungi as an effective approach to enhance the growth and metabolism of soybean plants under thallium (TI) toxicity

Thallium (TI) is a toxic metal that can trigger harmful impacts on growth and metabolism of plants. Utilizing arbuscular mycorrhizal fungi (AMF) proves to be an effective strategy for alleviating heavy metal toxicity in plants. To this end, AMF were applied to mitigate TI toxic effects on the growth, primary and secondary metabolism of soybean plants. Here, TI stress inhibited the growth and photosynthetic parameters of soybean plants. It also increased the oxidative damage as demonstrated by increased levels of oxidative markers, (MDA and lipoxygenase (LOX) activity). However, AMF could mitigate the reduction in growth and photosynthesis induced by TI, as well as the induction of oxidative damage. To overcome TI toxicity, AMF increased the levels and metabolism of osmolytes such as proline in soybean plants. This was in line with the increased activities of key enzymes that involved in proline biosynthesis (e.g., P5CS (pyrroline-5-carboxylate synthetase), P5CR (pyrroline-5-carboxylate reductase) and OAT (ornithine aminotransferase) under the AMF and/or TI treatments. Furthermore, soybean plants could benefit from the synergism between AMF and TI to enhance the contents of individual (e.g., spermine and spermidine) and total polyamines as well as their metabolic enzymes (e.g., arginine decarboxylase and ornithine decarboxylase). Overall, the combined application of AMF emerges as a viable approach for alleviating TI toxicity in soybean plants.

Effects of Interaction of Protein Hydrolysate and Arbuscular Mycorrhizal Fungi Effects on Citrus Growth and Expressions of Stress-Responsive Genes (Aquaporins and SOSs) under Salt Stress.

Protein hydrolysates (PHs) and arbuscular mycorrhizal fungi (AMF) are environmentally friendly biostimulants that effectively promote crop growth and alleviate the damage from abiotic stress. However, the physiological and molecular regulatory mechanisms are still unclear. This study aimed to explore the effects of PHs and AMF on growth, mineral nutrient absorption, and expression of Aquaporins and SOSs in Goutoucheng (Citrus aurantium) under salt stress. Results showed that PH application and AMF inoculation significantly promoted plant growth and enhanced mineral element absorption and sodium effluxion in citrus under salt stress. The biomass, root activity, leaves mineral nutrition contents in PHs, AMF, and combined (PHs and AMF) treatments were significantly higher than those of control. Leaves sodium content in three treatments was significantly lower than in the control. AMF and combined treatments showed dominant effects than PHs alone. Besides, PHs interacted with AMF on growth, nutrient absorption, and sodium effluxion. Importantly, AMF and PHs induced stress-responsive genes. PIP1, PIP3, SOS1, and SOS3 expression in PHs and AMF treatments was significantly higher than control. Thus, it was concluded that AMF and PHs enhanced the salt tolerance of citrus by promoting nutrient absorption and sodium effluxion via up-regulating the expression of PIPs and SOSs. The mixed application of PHs and AMF had a better effect.

Biological Control of Three Fungal Diseases in Strawberry (Fragaria × ananassa) with Arbuscular Mycorrhizal Fungi

Similar to many other plant-based products, strawberries are susceptible to fungal diseases caused by various pathogen groups. In recent years, efforts have been made to combat these diseases using biological control methods, particularly the application of arbuscular mycorrhizal fungi (AMF). This study aimed to determine the effects of AMF (Funneliformis mosseae (Fm) and Gigaspora margarita (Gm)) on Rhizoctonia fragariae (Rf), Fusarium oxysporum (Fo), and Alternaria alternata (Aa), which are major pathogens for strawberry. The results showed that the effects of AMF on disease severity and plant growth varied depending on the pathogens involved. Rf caused the highest disease severity, followed by Fo and Aa, but all AMF treatments significantly reduced the disease severity compared to control treatments. The study also found that the specific AMF species and their combinations influenced plant growth responses under different pathogenic conditions. Different AMF treatments resulted in varying increases in plant fresh weight, dry weight, and length, depending on the pathogen. Moreover, the application of AMF led to increased levels of total phenolic content, antioxidant activity, and phosphorus content in pathogen-infected plants compared to control treatments. Fm was more efficient than Gm in increasing these biochemical parameters. The levels of root colonization by AMF were similar among different AMF treatments, but the effects on fungal spore density varied depending on the pathogen. Some AMF treatments increased fungal spore density, while others did not show significant differences. In conclusion, our research sheds light on the differential effects of AMF species on disease severity, plant growth, and biochemical parameters in strawberry plants facing diverse pathogens. These findings underscore the potential benefits of AMF in disease management, as they reduce disease severity and bolster plant growth and defense mechanisms.

Effect of Arbuscular Mycorrhizal Tablets and Sachets on the growth of Pueraria javanica

Pueraria javanica (P. javanica) is a type of Leguminosae with a vine growth type with well-fixation nitrogen, so that can be used as a ground cover plant and forage food riched in protein (15-25%). In addition, the beneficial ability in symbiosis with arbuscular mycorrhizal fungi (AMF) has caused this plant to be utilized as the host plant for testing the effectiveness of different dosage forms of AMF on the growth of P. javanica which was carried out in Bukit Harapan sub-district, Parepare City at an altitude of 37.0 m asl with the coordinate point 3°59'30” S and 119°38'43” E. The study was conducted according to a randomized block design (RBD), AMF treatment dosage forms tested was powder (B1)/control, sachet (B2), and tablet (B3). The results showed that the form of AMF did not affect the effectiveness of stimulating the root length growth and volume, as well as the leaf number of P. javanica. AMF in tablet and sachet forms can enrich the AMF dosage form and can be a novelty for this field

Combined Application Effects of Arbuscular Mycorrhizal Fungi and Biochar on the Rhizosphere Fungal Community of Allium fistulosum L.

Arbuscular mycorrhizal fungi (AMF) are widespread soil endophytic fungi, forming mutualistic relationships with the vast majority of land plants. Biochar (BC) has been reported to improve soil fertility and promote plant growth. However, limited studies are available concerning the combined effects of AMF and BC on soil community structure and plant growth. In this work, a pot experiment was designed to investigate the effects of AMF and BC on the rhizosphere microbial community of Allium fistulosum L. Using Illumina high-throughput sequencing, we showed that inoculation of AMF and BC had a significant impact on soil microbial community composition, diversity, and versatility. Increases were observed in both plant growth (the plant height by 8.6%, shoot fresh weight by 12.1%) and root morphological traits (average diameter by 20.5%). The phylogenetic tree also showed differences in the fungal community composition in A. fistulosum. In addition, Linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed that 16 biomarkers were detected in the control (CK) and AMF treatment, while only 3 were detected in the AMF + BC treatment. Molecular ecological network analysis showed that the AMF + BC treatment group had a more complex network of fungal communities, as evidenced by higher average connectivity. The functional composition spectrum showed significant differences in the functional distribution of soil microbial communities among different fungal genera. The structural equation model (SEM) confirmed that AMF could improve the microbial multifunctionality by regulating the rhizosphere fungal diversity and soil properties. Our findings provide new information on the effects of AMF and biochar on plants and soil microbial communities.

Mechanisms associated with the synergistic induction of resistance to tobacco black shank in tobacco by arbuscular mycorrhizal fungi and β-aminobutyric acid.

Tobacco black shank (TBS), caused by Phytophthora nicotianae, is one of the most harmful diseases of tobacco. There are many studies have examined the mechanism underlying the induction of disease resistance by arbuscular mycorrhizal fungi (AMF) and β-aminobutyric acid (BABA) alone, but the synergistic effects of AMF and BABA on disease resistance have not yet been studied. This study examined the synergistic effects of BABA application and AMF inoculation on the immune response to TBS in tobacco. The results showed that spraying BABA on leaves could increase the colonization rate of AMF, the disease index of tobacco infected by P.nicotianae treated with AMF and BABA was lower than that of P.nicotianae alone. The control effect of AMF and BABA on tobacco infected by P.nicotianae was higher than that of AMF or BABA and P.nicotianae alone. Joint application of AMF and BABA significantly increased the content of N, P, and K in the leaves and roots, in the joint AMF and BABA treatment than in the sole P. nicotianae treatment. The dry weight of plants treated with AMF and BABA was 22.3% higher than that treated with P.nicotianae alone. In comparison to P. nicotianae alone, the combination treatment with AMF and BABA had increased Pn, Gs, Tr, and root activity, while P. nicotianae alone had reduced Ci, H2O2 content, and MDA levels. SOD, POD, CAT, APX, and Ph activity and expression levels were increased under the combined treatment of AMF and BABA than in P.nicotianae alone. In comparison to the treatment of P.nicotianae alone, the combined use of AMF and BABA increased the accumulation of GSH, proline, total phenols, and flavonoids. Therefore, the joint application of AMF and BABA can enhance the TBS resistance of tobacco plants to a greater degree than the application of either AMF or BABA alone. In summary, the application of defense-related amino acids, combined with inoculation with AMF, significantly promoted immune responses in tobacco. Our findings provide new insights that will aid the development and use of green disease control agents.