Mycorrhizal Treatments Research Articles

The Comprehensive Effects of Rhizophagus intraradices and P on Root System Architecture and P Transportation in Citrus limon L.

Both arbuscular mycorrhizal fungi (AMF) and phosphorus (P) collectively influence the root system architecture (RSA), but whether the combination of the two affects RSA, particularly lateral root formation, is unknown. In the present study, a pot experiment was conducted to evaluate the effects of an arbuscular mycorrhizal fungus (Rhizophagus intraradices) on the RSA of lemon (Citrus limon L.) seedlings under 0 (P0) and 50 mg/kg (P50) P levels. Moreover, P and carbohydrate content; acid phosphatase activity; and the expression of P transporter genes (PTs), phosphatase genes (PAPs), and lateral-root-related genes; were determined. Our results show that root mycorrhizal colonization and mycorrhizal dependency of lemon plants are significantly higher under P0 than under P50 conditions. AMF significantly promoted the plant growth performance of lemon, irrespective of substrate P levels. The RSA parameters of AMF plants, including total root length, projected area, surface area, average diameter, volume, and second- and third-order lateral root numbers, were distinctly increased under the two P levels compared to those of non-AMF plants. Mycorrhizal treatment also induced higher carbohydrate (sucrose, glucose, and fructose) and P contents, along with a higher activity of root acid phosphatase. The expression of P-related genes, including ClPAP1, ClPT1, ClPT3, ClPT5, and ClPT7, as well as the expression of lateral-root-related genes (ClKRP6, ClPSK6, and ClRSI-1), was dramatically upregulated by AMF inoculation, irrespective of substrate P levels. Principal component analysis showed that root P and carbohydrate contents, as well as the expression of ClKRP6 and ClPSK6, were positively correlated with RSA traits and lateral root development. Our study demonstrates that mycorrhizas accelerate the P acquisition and carbohydrate accumulation of lemon plants by upregulating the expression of lateral-root-related genes, thereby positively improving the RSA. Furthermore, AMF had a greater impact on the RSA of lemon than substrate P levels.

Mycorrhiza improves plant growth and photosynthetic characteristics of tea plants in response to drought stress

Tea plants are sensitive to soil moisture deficit, with the level of soil water being a critical factor affecting their growth and quality. Arbuscular mycorrhizal fungi (AMF) can improve water and nutrient absorption, but it is not clear whether AMF can improve the photosynthetic characteristics of tea plants. A potted study was conducted to determine the effects of Claroideoglomus etunicatum on plant growth, leaf water status, pigment content, gas exchange, and chlorophyll fluorescence parameters in Camellia sinensis cv. Fuding Dabaicha under well-watered (WW) and drought stress (DS) conditions. Root mycorrhizal colonization and soil hyphal length were significantly reduced by the eight-week DS treatment. AMF inoculation displayed a significant increase in shoot and root biomass production. The relative water content, leaf water potential, nitrogen balance index, pigment content, maximum photometric effect (Fv/Fm, QY_max), and steady-state photometric effect Y (II) (QY_Lss) decreased dramatically, while the leaf water saturation deficit and steady-state non-photochemical fluorescence quenching (NPQ_Lss) generally increased under DS conditions. Mycorrhizal treatment induced significantly higher relative water content, leaf water potential, nitrogen balance index, pigment (chlorophyll, flavonoid, and anthocyanin) content, net photosynthesis rate, transpiration rate, stomatal conductance, intercellular CO2 concentration, QY_max, and QY_Lss; however, it resulted in a lower leaf water saturation deficit and NPQ_Lss under both WW and DS conditions, as compared with non-mycorrhizal plants. These results imply that AMF promoted tea plant growth and alleviated negative effects of DS by promoting gas exchange, regulating the water status of leaves, and regulating photosynthetic parameters.

Intensitas Penyakit pada Tanaman Ciplukan (Physalis angulata L.) yang Diberikan Kombinasi Perlakuan Pupuk Hayati (Mikoriza) dan Organik

Ciplukan plant is a plant that has potential to be used as a medicinal plant because it has various bioactive contents. Several studies that have been carried out are still limited to the potential, content and benefits of ciplukan plants. The aspect of disease attack on ciplukan plants, there has not been much research, even though this plant has various benefits and is currently being developed. This is what underlies this research. If previous research used organic and chemical fertilizers, it is also necessary to compare using biological fertilizers derived from mycorrhizal fungi against diseases found in ciplukan plants. The stages of the research carried out were planting preparation and application, observation, maintenance and data analysis. The aim of research was to determine the types and symptoms of disease, as well as important diseases-causing pathogens in ciplukan plants and the effect of a combination of biological (mycorrhizal) and organic fertilizers on diseases intensity. The results of the research obtained two types of diseases that occurred in ciplukan plants, namely leaf spot symptoms caused by Cercospora sp. and curly leaf symptoms caused by Cucumber Mosaic Virus (CMV). The combination of mycorrhizal treatment and organic fertilizer (manure) tends to increase the intensity of leaf spot disease and the incidence of curly leaf diseases.

Mycorrhizal-Assisted Phytoremediation and Intercropping Strategies Improved the Health of Contaminated Soil in a Peri-Urban Area.

Soils of abandoned and vacant lands in the periphery of cities are frequently subjected to illegal dumping and can undergo degradation processes such as depletion of organic matter and nutrients, reduced biodiversity, and the presence of contaminants, which may exert an intense abiotic stress on biological communities. Mycorrhizal-assisted phytoremediation and intercropping strategies are highly suitable options for remediation of these sites. A two-year field experiment was conducted at a peri-urban site contaminated with petroleum hydrocarbons and polychlorinated biphenyls, to assess the effects of plant growth (spontaneous plant species, Medicago sativa, and Populus × canadensis, alone vs. intercropped) and inoculation of a commercial arbuscular mycorrhizal and ectomycorrhizal inoculum. Contaminant degradation, plant performance, and biodiversity, as well as a variety of microbial indicators of soil health (microbial biomass, activity, and diversity parameters) were determined. The rhizosphere bacterial and fungal microbiomes were assessed by measuring the structural diversity and composition via amplicon sequencing. Establishment of spontaneous vegetation led to greater plant and soil microbial diversity. Intercropping enhanced the activity of soil enzymes involved in nutrient cycling. The mycorrhizal treatment was a key contributor to the establishment of intercropping with poplar and alfalfa. Inoculated and poplar-alfalfa intercropped soils had a higher microbial abundance than soils colonized by spontaneous vegetation. Our study provided evidence of the potential of mycorrhizal-assisted phytoremediation and intercropping strategies to improve soil health in degraded peri-urban areas.

Mitigation of Salt Stress by Mycorrhizal Inoculation on Nitraria schoberi as a Native Landscape Plant in the Arid regions

Increasing the salinity in the water and soil can negatively affect plant growth and development. Mycorrhizal fungi application is one of the ways to reduce the undesirable effect of salt stress on plants. An experiment was conducted in 2017 to assess the effect of salt stress on Nitraria schuberi, as a native Iranian plant in arid regions, inoculated with mycorrhizal fungi. Seedlings of this plant were treated under three different levels of NaCl in three stages. The stages including low salt concentrations (0, 20, 60, and 100 mM NaCl), medium salt concentrations (0, 40, 120, and 200 mM NaCl) and high salt concentrations (0, 80, 240, and 400 mM NaCl). Mycorrhizal treatment including two levels: non-inoculated (control) and mycorrhizal inoculated. Experimental designs were factorials (4×2 treatments) based on the completely randomized design with four replications. In this study, the content of chlorophyll, carotenoid, sugar, proline and Na, Mg, K, Fe and Ca were measured. The results indicated that with increasing salinity levels from the first (low) to third (high) stage, chlorophyll content was decreased while carotenoid, proline, and sugar were increased. The application of NaCl salinity led to a reduction in Fe and enhancement in Na. In the mycorrhizal plants, sugar content decreased but magnesium, calcium and potassium levels increased. Based on these findings it seems that Nitraria schuberi is a salt tolerant plant and mycorrhizal fungi can mitigate salinity stress in this plant. Therefore this plant could be applied in the urban landscape of arid and semi-arid regions.

Synergistic effects of inoculating AMF and foliar iron fertilizer on growth and yield of broad bean under North Sinai conditions

This work was undertaken at the Experimental Farm of Fac. Environ. Agric. Sci., Arish University, North Sinai, Egypt, during the successive winter seasons of 2016/2017 and 2017/2018. The synergistic effects of inoculating AMF and foliar iron (Fe) fertilizer on spore counts, mycorrhizal colonization, formation of nodules, plant growth and yield parameters of broad bean plant (Vicia faba L.) grown in sandy loam soil were studied. This work included two studied factors: Two mycorrhizal treatments (Inoculum AMF and Natural AMF) and five foliar Fe concentrations (0.0, 300, 400, 500 and 600 ppm) and their interactions. The obtained results revealed that application of inoculated AMF and spray with Fe at 400 ppm increased spore count and root colonization. However, total number of active nodules/plant increased with inoculated AMF and spraying iron at 600 ppm. Results indicated the superiority interaction treatment of inoculated AMF with the foliar Fe at the concentration of 500 ppm by which it recorded the highest values of plant growth traits; viz, root length, number of branches/plant, total dry weight/plant and photosynthetic pigments content in both seasons. Moreover, the same treatment recorded the highest values with all pod characters and yield, except weight of number of green seeds/pod in first season and average pod weight (g) in the second one.

Cell wall modification induced by an arbuscular mycorrhizal fungus enhanced cadmium fixation in rice root

The chemistry of root cell wall of rice could be changed by inoculation of arbuscular mycorrhizal fungi (AMF). Hydroponic experiments were conducted to investigate the roles of such changes on cadmium (Cd) uptake and distribution in rice. Results showed that inoculation of AM fungus Rhizophagus intraradices (RI) significantly enhanced (p < 0.05) shoot biomass, plant height and root length of rice, and decreased Cd concentration in shoot and root under Cd stress. Moreover, Cd in root was mainly found in pectin and hemicellulose 1 (HC1) components of root cell wall. Inoculation of RI increased the levels of pectin, HC1 and lignin content, accompanied by the increments of L-phenylalanine ammonia-lyase (PAL) and pectin methylesterase (PME) activities. Results of Fourier transform infrared spectroscopy further showed that more hydroxyl and carboxyl groups in root cell wall were observed in mycorrhizal treatment, compared with control. This study demonstrates that cell wall components could be the locations for Cd fixation, which reduced Cd transportation from root to shoot. Inoculation of AMF may remodel root cell wall biosynthesis and affect the characteristics of Cd fixation. The entering and fixing mechanisms should be further studied.

Effect of cadmium on sorghum root colonization by glomeral fungi and its impact on total and easily extractable glomalin production.

Glomalin is a specific glycoprotein compound synthesized by glomeral fungi and its amount varies according to soil conditions. Due to the symbiosis of these fungi with a multitude of plants, a remarkable amount of glomalin is produced inside the hypha wall of these fungi. Furthermore, while increasing the symbiosis stability, glomalin plays a critical role in reducing the availability of potentially toxic elements (PTEs) through their fixation. In this regard, soil contamination with PTEs such as cadmium (Cd) affects the glomalin production of mycorrhiza fungi. In order to investigate the effect of different levels of Cd on glomalin production of three species of arbuscular mycorrhiza fungi in the presence of sorghum, a greenhouse experiment was conducted in a completely randomized design with factorial arrangement and three repetitions. Factors include four levels of Cd (0, 5, 10, 20 milligrams per kilogram of soil) and second factor included these three types of mycorrhiza: Funneliformis mosseae (FM), Rhizophagus intraradices (RI), and Claroideoglomus etunicatum (CE). The results of this study showed that when increasing soil Cd concentration, shoot dry weight, root colonization percentage, total and easily extractable glomalin decreased while leaf proline concentration, shoot, and root Cd concentration increased. The presence of mycorrhiza in comparison with the control increased the dry weight of shoots and plant height. The results showed that mycorrhizal treatments increased total and easily extractable glomalin compared to the absence of mycorrhiza. Also, the highest amount of glomalin production was observed in two species of FM and CE. Complexation of Cd by total glomalin and easily extractable glomalin was higher in two species of FM and CE rather than RI. The results showed that the use of three species of mycorrhizae reduced the adverse effects of high levels of Cd. Also, the concentration of leaf proline, soluble sugars, shoot, and root Cd concentration was higher in presence of mycorrhizal fungal species than in plant not inoculated with mycorrhizal fungal species. This increase was significant in both FM and CE species. Finally, a notable positive correlation was also observed between glomalin measured by Bradford method and percentage of root colonization.

Arbuscular mycorrhizal fungi improve uptake and control efficacy of carbosulfan on Spodoptera frugiperda in maize plants.

Inoculation of arbuscular mycorrhizal (AM) fungi in soil can promote the uptake of nutrients and xenobiotics by plants. In this study, the effects of arbuscular mycorrhizal fungi (including Glomus intraradices and Glomus mossea) on the growth of maize, the uptake of carbosulfan and the control efficacy on Spodoptera frugiperda were investigated through maize seed coating. Results from the pot experiment showed that carbofuran reduced the mycorrhizal colonization of AM fungi in the early stage of the experiment. The inhibiting effect disappeared in 21-49 DAP, whereas the mycorrhizal colonization rate under the G.intraradices treatment was maintained at ≈90%. Compared with noninoculated treatment, the fresh weights of roots in G.intraradices and G.mosseae treatments increased by 20-41% and 10-23%, respectively. Mycorrhizal treatment could significantly increase the transmission rates (root/soil and leaf/stem) and the carbosulfan accumulation in maize. During the harvest period, the control efficacy against S.frugiperda in mycorrhizal treatment was significantly higher than that in noninoculated treatments (P < 0.05) in both Guangzhou and Nanning. Inoculation with AM could accelerate the degradation process of carbofuran in soil and the propagation of carbofuran from soil to plants. Glomus intraradices showed more pronounced effects than G.mosseae on both plant growth and carbosulfan content in plants and soil. The experimental results showed that inoculation of AM fungi increased the accumulation of carbofuran in plants, improved the effective utilization rate and enhanced the control efficacy against S.frugiperda. © 2021 Society of Chemical Industry.

Mycorrhizae, elemental sulfur and phosphorus effects on pepper yield and nutrient uptake

Aims: Fertilization contributes to the yield in agriculture. The objective of this study was to determine the effects of mycorrhizae and fertilization of phosphorus (P) and elemental sulfur (ES) on yield responses, root mycorrhizal inoculation level, root to shoot ratio and nutrient uptake of green pepper (Capsicum annuum L.).Methods and Results: 100 mg kg-1 ES and/or 100 mg kg-1 P fertilizers were added with and without mycorrhizal inoculation into the soil. Green pepper was grown for 45 days on calcareous sterilized Karaburun soil. Root and shoot yield increased by mycorrhizal inoculation compared to the control treatment. While fertilization with ES or P alone resulted in yield increase in the non-mycorrhizal treatments, the reverse was the case in the mycorrhizal treatments. The combined effect of ES and P fertilization comparing P fertilization alone decreased the yield in the non-mycorrhizal tratments while the reverse was the case in the mycorrhizal treatments. Root to shoot ratios and shoot nutrient concentrations changed in both directions as independent from the yield and treatments. ES and/or P addition decreased insignificantly mycorrhizal inoculation level.Conclusions: Obtained results indicated that ES and/or P fertilization affect yield of pepper, nutrient uptake, root to shoot ratio in both ways with insignificantly decreased root mycorrhizal infection level.Significance and Impact of the Study: ES and/or P fertilization with mycorrhizal inoculation is important to get higher yield. For that reason, this study provides data about appropriate fertilizer or fertilizer combinations to prevent yield loss of pepper in mycorrhizal and non-mycorrhizal growth conditions.

Effects of Arbuscular Mycorrhizal Fungi on Root Growth and Architecture of Tulip Gesneriana

Arbuscular mycorrhizal fungi(AMF) can promote the absorption of soil water and mineral nutrients, improve photosynthesis, and make host attain higher quality finally by establishing symbiotic relationship between AMF and host root. To improve Tulip gesneriana quality have practical meaning under no bad affect to cultivation soil, in the light of its economical and ecological values. However, some AMF may be diverse from others, the concrete function of AMF on commercial tulip varieties need to explore. Therefore, three different sets of arbuscular mycorrhizal fungi were inoculated into tulip rhizosphere soil, which were set as 4(Diversispora versiformis), 7(Diversispora spurca) and 1 + 3 + 4 (Rhizophagus intraradias + Funneliformis mosseae + Diversispora versiformis), respectively. The results showed that the activity of most of the measured indices increased, the average root diameter and sucrose content decreased in those three mycorrhizal treatments. Our research provide some theoretical basis for the application of AMF on T.gesneriana ecological cultivation in future.

Interactive effects of boron stress and mycorrhizal (AMF) treatments on tomato growth, yield, leaf chlorophyll and boron accumulation, and fruit characteristics

ABSTRACT High levels of boron (B) in soils cause toxicity in tomatoes, but inoculation of arbuscular mycorrhizal fungi (AMF) into plants can reduce it. This study aimed to evaluate the effects of AMF inoculation on morphological parameters (shoot height, plant fresh and dry weights), yield, leaf chlorophyll and boron content, and fruit characteristics (weight, water and soluble solid contents, firmness, color) of tomato plants grown in boron stress (0.06, 0.5, 1.0, 2.0, 4.0, and 8.0 mM). Increased boron concentrations reduced all parameters except leaf boron content, fruit soluble solids and firmness. However, the highest values of the morphological parameters, fruit soluble solid contents and red color values (control, 0.5 and 1.0 mM B), fruit yield (<8.0 mM B), leaf chlorophyll content (≤2.0 mM B), fruit weight (control, 0.5 and 2.0 mM B), fruit firmness (control and 1.0 mM B) were obtained from mycorrhizal plants. No significant differences were found between the fruit water content and color values (brightness and yellow) of non-mycorrhizal and mycorrhizal plants in all boron stress levels. The leaf boron concentration in inoculated with mycorrhizal fungi had lower than non-inoculated ones. These results suggest that mycorrhizal-inoculation may limit excessive boron uptake and alternatively be used in boron contaminated soils.

Comparison of Effectiveness of Arbuscular Mycorrhiza Fungi (AMF) on Vitis vinifera under Low Irrigation Conditions

Background: Grapevine is an important perennial crop worldwide, consumed as fresh or dried (raisins) fruit. Grapevines are exposed to a variety of abiotic stresses during their growth. Water shortage is one of the primary stressors and severely restricts the development of the grape industry. Arbuscular mycorrhizal fungi (AMF), a kind of beneficial soil microorganism, can create a symbiotic association with plant roots forming arbuscular mycorrhizas (AMs), which play a role in the regulation of plant growth. Methods: This research was accomplished in order to investigate the effect of 4 species mycorrhizal fungi on grapevine ‘Asgari’ cultivar under water stress conditions. We use of 3 irrigation regime that consist: 100% (as control), 70 and 40 % of field capacity. As well as, mycorrhizal treatments include: non-use of mycorrhizal (NM) and use of mycorrhiza (M) (Glomus mosseae, G. intraradices, G. etunicatum and G. verciform). Result: The results indicated that shoot and root dry weight, pigments (total chlorophyll and carotenoids), relative water content (RWC), P, Mg2+ and Ca2+ under water limitation decreased but electrolyte leakage (EL), proline and total soluble sugars (TSS) increased chlorophyll content, RWC and nutrient (P, K+ and Ca2+) in M plants was higher than NM plants. Generally, the use of mycorrhiza fungi in this experiment reduced the harmful effects of water stress. Our results shown that G. verciform and G. etunicatum were better for symbiosis with “Asgari” grapevine under water limitation.

Dynamics of soil fertility as influenced by intercropping systems, mycorrhizal inoculation and fertilizer levels in maize-sunflower cropping system

Field experiments were conducted for two consecutive years (2010-11 and 2011-12) at Eastern Block Farm, Tamil Nadu Agricultural University, Coimbatore on sandy clay loam soils consisting sunflower was raised as residual crop during summer in a sequence of maize sown in winter. The experiments were laid out in split-split plot design with three factors. In respect of succeeding crop sunflower, all the treatment plots were further divided into two equal parts by adopting the following treatment schedule. Three intercropping systems viz., sole maize - sunflower (I1), maize+cowpea - sunflower (I2) and maize+ greengram - sunflower (I3) were the treatments under main plot. Four mycorrhizal treatments viz., M1 - uninoculated (Both crops), M2 - uninoculated (Sunflower), M3 - inoculated (Sunflower), M4 - inoculated (Both crops) were included under sub plot. Three fertilizer levels viz., 75% RDF (F1), 100% RDF (F2), and 125% RDF (F3) under sub-sub plot. Regarding the dynamics of various soil fertility parameters viz., N, P and K uptake of sunflower were found higher to a considerable extent under preceding maize + cowpea intercropping followed by maize + greengram intercropping at both the stages. With respect to mycorrhizal inoculation, nutrient uptake was higher under mycorrhiza inoculated treatments for both the crops over uninoculated treatments. Among the fertilizer levels, 125% RDF to preceding maize recorded higher N, P and K uptake followed by 100% RDF at both the stages of observation. With regard to soil available nutrients, among the intercropping systems, preceding sole maize registered higher soil available N, P and K followed by maize + cowpea intercropping. Among the mycorrhizal treatments, mycorrhiza uninoculated to both the crops and among the fertilizer levels, 125% RDF recorded higher soil available nutrients. As regards the balance sheet of soil available N, P and K,lower actual N loss was (-32.7 kg ha-1), P loss was (-1.2 kg ha-1) and K loss was (-22.1 kg ha-1) under the treatment combination maize + cowpea intercropping along with mycorrhizal inoculation to both the crops and 125% RDF (I2F3M+) during 2011. Regarding 2012, the maximum actual N gain was (5.0 kg ha-1), P gain was (0.1 kg ha-1) and K gain was (12.3 kg ha-1) under the treatment combination maize + cowpea intercropping along with mycorrhizal inoculation to both the crops with 125% RDF (I2F1M+). The maximum actual loss was recorded under the treatment combination of sole maize without mycorrhizal inoculation to both the crops with 75% RDF.

Arbuscular mycorrhizal fungi mediated salt tolerance by regulating antioxidant enzyme system, photosynthetic pathways and ionic equilibrium in pea (Pisum sativumL.).

Arbuscular mycorrhizal (AM) fungi play an important role in improving the plant tolerance to salt stress. In the present study, we investigated the influence of AM fungi inoculation on various physiological, biochemical and nutritional aspects of pea grown under salt stress. The AM fungi inoculation successfully reduced the negative effects of salinity by improving the antioxidant enzyme system, a greater accumulation of compatible organic solutes, a higher content of photosynthetic pigment and a balanced uptake of nutrients, which resulted in higher growth and yield. Seed yield was found to be significantly higher by ~ 24, 40 and 54% in T2 (Rhizoglomusintraradices), T3 (Funneliformis mosseae and R. intraradices) and T4 (Rhizoglomus fasciculatum and Gigaspora sp.), respectively, as compared to nonmycorrhizal plants. Overall, a mixed application of Rfasciculatum and Gigaspora sp. was superior to other mycorrhizal treatments, which can be attributed to specific compatibility relationships or functional complementarity that exists between symbionts.

Uji Efektifvitas Cendawan Mikoriza Lokal Gerogak Lahan Kering dan Komersial Pada Tanaman Jagung (Zea mays L.)

Dryland in Indonesia has been dominated by acid soils, so that availability of phosphate (P) becomes the main obstacle in improving outcomes and only 10-30% of fertilizer P can be utilized by plants. One of the solution to meet the needs of phosphate is by utilization of mycorrhizal biofertilizer. These experiments were divided into several phases: 1) Looking for phases of mycorrhizal, 2) the laboratory analysis, 3) Testing phase on plants that were carried out by using polybags with sterile soil. The experiment was designed with a complete randomized block design (RAKL) by using a factor that consists of 6 treatments that are: 1) Without mycorrhizal inoculum (M0), 2) Mycorrhizal inoculum 5 g + 50 Spores (M5), 3) Mycorrhizal inoculum 10 g + 50 spores (M10), 4) Mycorrhizal inoculum 15 g + 50 spores (M15), 5) Mycorrhizal inoculum 20 g + 50 spores (M20), 6) Commercial mycorrhizal 10 g (Mk). All treatments were repeated four times so that the total 24 pot experiment. The experiment results show that mycorrhizal treatment given on the corn crop has very significant (P &lt;0.01) to the number of leaf age of 35, 49, 63 days after, leaf wide have age 49 days after plant, fresh weight, oven-dry weight, absorb P, number of spores, mycorrhizal infection and significant effect (P &lt;0.05) to plant height age of 35, 49, 63 day after plant, 63 days after plant, leaf wide, and P-available. Based on the results of this study will be suggested, in order to enhance the growth of corn plants can be used locally mikroiza a dose of 10 g + 50 spores.

The Effect of Arbuscular Mycorrhizal Fungi Inoculation in Mitigating Salt Stress of Pea (Pisum Sativum L.)

ABSTRACT Salinity is one of the major threats to an agriculture production system and limits crop growth and productivity. Arbuscular mycorrhizal fungi (AMF) form a mutualistic association with majority of land plants and play important role in stress tolerance. In the present study, effect of three mycorrhizal treatments, i.e., single-species AMF (Rhizoglomus intraradices), formulated AMF (Funneliformis mosseae and R. intraradices), and multispecies AMF (Rhizoglomus fasciculatum and Gigaspora sp.) along with control (nonmycorrhizal) on growth, yield performance, and metabolic changes in pea crop under salinity stress was examined in completely randomized design with four replications. The results revealed that AMF inoculation mitigated negative effects of salinity in pea due to higher nutrient uptake, accumulation of compatible osmolytes, and lower cellular leakage of electrolyte which in turn enhanced biomass production, chlorophyll synthesis, yield, and growth attributes. Overall, consortium-based application of R. fasciculatum and Gigaspora sp. was found most suitable approach to ameliorate the salt stress in pea crop and enhanced the yield by ~11%, 24%, and 54% than single-species, multispecies, and control treatments, respectively. The variation in results under different mycorrhizal treatment might be due to specific compatibility relationships that exist between symbionts.

Mycorrhizal Fungi and Thiobacillus Co-inoculation Improve the Physiological Indices of Lallemantia iberica Under Salinity Stress.

Salinity, a serious environmental pressure on crop production, might be counteracted by free-living and symbiotic inoculants entailing positive synergistic effects. Enhancement in nutrient uptake and/or production of antioxidants under the stress condition, can improve plant growth and yield. In this study, inoculation of Lallemantia iberica with Funneliformis mosseae and the sulfur solubilizing bacterium (Thiobacillus sp. T95 and T40) was evaluated under two salinity levels (6.72 dS/m and 0.91 dS/m as control). The root colonization, spore density, seed and biological yield, total soluble sugars, and nutrients were reduced by salt stress. Antioxidant enzyme activity (catalase, superoxide dismutase, peroxidase and ascorbate peroxidase), proline, contents of sodium and sulfur have increased under salt stress. The enzyme activities as well as the concentrations of nitrogen, phosphorus, potassium, sodium, and sulfur were dropped at the flowering stage (75days after sowing). Seed and biological yield, antioxidant enzymes activity, proline content, and nutrients were significantly improved in mycorrhizal treatments. Inoculation of Thiobacillus exhibited the positive effect on root colonization, spore density, enzymes activity, and nutrients. Bacterial treatments (dual and single) significantly increased the sulfur and total soluble sugars. Totally, the mycorrhizal plants accumulated more enzymatically produced antioxidants, osmolytes, and showed improved nutrient uptake. Our results provide new insights into the relationship among arbuscular mycorrhizal fungi (AMF), biosulfur bacteria, and plant growth under saline conditions. In conclusion, the Lallemantia iberica inoculation with mycorrhizal fungi, either alone, or in combination with Thiobacillus, is indicated for optimum plant yield through alleviation of the salinity stress.

Conservation of Picrorrhiza kurroa with arbuscular mycorrhizal fungi: An endangered and highly economic medicinal herb of Himalaya

Arbuscular mycorrhizal (AM) fungi are prevalent from arctic to tropics in most agricultural and natural ecosystems, play an important role in the conservation of some valuable medicinal plants. Picrorrhiza kurroa Royle ex Benth is distinguished endangered medicinal herb, naturally distributed in alpine and sub-alpine region of Himalayas. In present investigation, spores density of AM fungi along root colonization were studied from the rhizospheric soils of P. kurroa collected from different locations of Himachal Pradesh. Highest spore number (60) was found in the soil samples collected from forest nursery Rajkunda while AM root space colonization was highest in the samples of forest nursery Devidhar. The biodiversity of AM fungi was studied; the number of AM species was also highest in these two forest nursery samples. Funneliformis mosseae and Acaulospora laevis were dominant species associated with P. kurroa. After mass multiplication of F. mosseae and A. laevis, bioinoculation experiment was performed on Picrorrhiza kurroa seedlings for the biomass production and nutrient uptake analysis. Seedlings were inoculated with single and in combined mycorrhizal treatments with different combinations of farmyard manure and vermicompost. All inoculated seedlings showed significant biomass production than control seedlings. Root length (8.7cm), fresh and dry biomass was observed to be maximum in the plants inoculated with F. mosseae and vermicompost @ 10t ha−1 while percent AM root colonization was highest (60.33) in the roots of plants inoculated with F. mosseae plus A. laevis with vermicompost @10t ha−1. The phosphorus content was more in seedlings inoculated with consortium of two native AM fungi followed by F. mosseae and A. laevis, separately. In overall, consortium of native AM fungi i.e. F. mosseae and A. laevis was found to be best for the conservation of the P. kurroa in the presence of vermicompost and FYM, respectively.

Mycorrhiza Regulates Signal Substance Levels and Pathogen Defense Gene Expression to Resist Citrus Canker

Citrus canker is a quarantined disease, severely harming citrus plants. Soil beneficial arbuscular mycorrhizal fungi (AMF) can provide a biological control pathway to resist pathogens. This work was to test changes of signal substances including hydrogen peroxide (H2O2), nitric oxide (NO), calmodulin (CaM), salicylic acid (SA) and jasmonic acid (JA) and the pathogen defense gene expression in roots of AMF (Paraglomus occultum) and non-AMF trifoliate orange (Poncirus trifoliata) seedlings after infected by a expressions citrus canker pathogen (Xanthomonas axonopodis pv. Citri, Xac). AMF inoculation significantly improved plant height, stem diameter and leaf number. Xac infection dramatically decreased root H2O2, NO, and SA levels, but increased root CaM and JA concentrations in non-AMF seedlings. There were higher H2O2 and CaM levels and lower JA levels in Xac-infected seedlings than in non-Xac-infected seedlings under mycorrhization. Under non-Xac infection, mycorrhizal treatment reduced root H2O2, NO, and SA but increased CaM and JA levels. However, under Xac infection, mycorrhizal inoculation distinctly accelerated root H2O2, NO, CaM, and SA accumulation, accompanied with up-regulated expression levels of root PtEPS1 (enhance pseudomonas susceptibility 1) and PtPR4 (pathogenesis related gene 4), indicating that Xac stimulated mycorrhizal roles in enhancing resistance of citrus canker. Such results imply that citrus plants with pre-inoculated AMF had stronger resistance to Xac infection through increasing signal substrate accumulation and pathogen defense gene expressions.&#x0D; &#x0D; *********&#x0D; In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.&#x0D; *********