Arbuscular Mycorrhizal Fungi Inoculation Research Articles

Effects of Interaction between Claroideogolmus etuicatum and Bacillus aryabhattai on the Utilization of Organic Phosphorus in Camellia oleifera Abel.

Arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) are involved in phosphorus (P) mobilization and turnover; however, the impact of their interaction on plant P absorption and organic P mineralization in the hyphosphere (rootless soil) are unknown. This study examined the interactive effects of two native microorganisms, namely Claroideogolmus etuicatum and Bacillus aryabhattai, and the effects of co-inoculation of both microorganisms on organic P mineralization and the subsequent transfer to Camellia oleifera, using a three-compartment microcosm with a nylon mesh barrier. The results demonstrated that the co-inoculation treatment (AMF + PSB) significantly increased the plant P content and biomass accumulation in C. oleifera compared to those of the non-inoculated control. Furthermore, co-inoculation boosted soil phosphatase and phytase activities as well as the liable P content. Compared to the non-inoculated control, inoculation of AMF decreased the NaOH-Po content. A correlation analysis showed that AMF colonization and hyphal density was significantly positively correlated with H2O-P and NaHCO3-Pi and negatively correlated with NaOH-Po. It was shown that co-inoculation could increase phosphatase activity, phytase activity, and promote the liable P content, thus increasing the phosphorus content and biomass accumulation of C. oleifera. In conclusion, AMF and PSB interactively enhanced the mineralization of soil organic P, and therefore positively affected P uptake and plant growth.

Arbuscular Mycorrhizal Fungi Restored the Saline-Alkali Soil and Promoted the Growth of Peanut Roots.

Peanut (Arachis hypogaea L.) is an important oil and cash crop. An efficient utilization of saline-alkali soil resources, the development of peanut planting in saline-alkali soil, and obtaining high and stable yield have become urgent needs to ensure peanut production. Arbuscular mycorrhizal fungi (AMF) have been reported to develop the potential productivity of host plants and improve their salt resistance and tolerance. However, there is still limited research on promoting the growth and morphology of peanut roots. Therefore, in this study, seeds of salt-tolerant peanut variety "HY 25" were coated with commercial AMF inoculant before being planted in saline-alkali and normal soils to investigate the effects of AMF on peanut root growth and rhizosphere soil. The results showed that root morphological characteristics were significantly increased by the use of AMF at the podding stage in saline-alkali soil and from the flowering and pegging stage to the maturity stage in normal soil. Of note, the total root volume of peanut inoculated with AMF significantly increased by 31.57% during the podding stage in saline-alkali soil. Meanwhile, AMF significantly increased the phosphatase and invertase activities in the peanut rhizosphere of saline-alkali soil from the flowering stage to maturity stage and soil CAT activity at the maturity stage (41.16~48.82%). In normal soil, soil phosphatase and urease activities were enhanced by AMF at the flowering stage and the podding stage, respectively. AMF also increased the contents of soil organic matter, available phosphorus, and hydrolysable nitrogen, but decreased soil EC in saline-alkali soil. In addition to the significant increase in soil available phosphorus content, AMF had no significant effect on the physical and chemical properties of the soil and other soil nutrients in normal soil. AMF significantly increased pod biomass and yield in saline-alkali soil and normal soil, and improved their agronomic characteristics. In conclusion, peanut seeds coated with AMF improved the root morphological characteristics of peanuts and improved the physical and chemical properties in peanut rhizosphere, especially in saline-alkali soil. The process of rhizosphere soil nutrient transformation was also enhanced. Finally, AMF improved plant agronomic traits to increase the pod yield (16.5~21.9%). This study provides the theoretical basis and technical support for the application of AMF in peanut production in saline-alkali soil.

Arbuscular mycorrhizal fungi alter rhizosphere bacterial diversity, network stability and function of lettuce in barren soil

Arbuscular mycorrhizal fungi (AMF) play an important role in plant growth and rhizosphere microbiome composition. However, how the plant-AMF-rhizosphere microbiome continuum interacts in barren soils to efficiently promote the plant's growth is still an area of little research. Here, we present the results of a controlled environment experiment to reveal the effect of AMF on the rhizosphere bacterial community of lettuce. Compared with the control group, AMF significantly increased plant biomass, mycorrhizal colonization, and affected the rhizosphere microbial community composition. AMF inoculation changed the function of the rhizosphere bacterial community, reduced the complexity of the bacterial network, and improved its stability. In addition, SEM showed that the composition and structure of rhizosphere soil bacterial community were significantly positively correlated with soil carbon, nitrogen, and phosphorus content after adding AMF. Our findings provide new information for exploring the positive effects of plant-microbe interactions.

Effect of AM Fungi on Antioxidant Enzymes Activity in Tomato (Solanum lycopersicum L.)

Arbuscular mycorrhizal fungi (AMF) have been used to enhance the plant growth and yield to maintain good health and fertility that contributes great extents to a sustainable product. The study was undertaken to identify the responses of antioxidant enzymes activities in tomato (Solanum lycopersicum L.Var PMK 1 and Vaibhav) inoculated with AM fungi. The Arbuscular mycorrhizal fungi (AMF) increased the antioxidant enzyme activities such as Superoxide dismutase (SOD) and Catalase (CAT) activity in roots of inoculated plants, indicating lower oxidative damage in the colonized plants. It can be concluded that the mycorrhiza helps tomato plants by enhancing the antioxidant activity compared to non-mycorrhizal plants. Therefore, inoculation of indigenous AM fungi is recommended at seedling stage.

Integrative application of biochar and arbuscular mycorrhizal fungi for enhanced chromium resistance in Medicago sativa

Soil chromium (Cr) contamination has become an environmental problem of global concern. However, the joint effects of combined utilization of biochar and arbuscular mycorrhizal (AM) fungal inoculum, which are considered as two promising remediation strategies of soil heavy metal pollutions, on plant Cr resistance are still poorly understood. In this study, a two-factor pot experiment was conducted to investigate how biochar and AM fungus Rhizophagus irregularis regulate Medicago sativa growth, physiological trait, nutrient and Cr uptake, relevant gene expressions, soil properties, and Cr speciation, independently or synergistically. The results showed that biochar notably decreased AM colonization, while biochar and AM fungus could simultaneously increase plant dry biomass. The greatest growth promotion was observed in mycorrhizal shoots at the highest biochar level (50 g kg−1 soil) by 91 times. Both biochar application and AM fungal inoculation enhanced plant photosynthesis and P nutrition, but the promoting effects of AM fungus on them were significantly greater than that of biochar. In addition, the combined application of biochar and AM fungus dramatically reduced shoot and root Cr concentrations by up to 92 % and 78 %, respectively, compared to the non-amended treatment. Meanwhile, down-regulated expressions were observed for metal chelating-related genes. Furthermore, Cr translocation from roots to shoots was reduced by both two soil amendments. Transcriptional levels of genes involved in reactive oxygen species and proline metabolisms were also regulated by biochar application and AM fungal colonization, leading to alleviation of Cr phytotoxicity. Furthermore, AM fungal inoculation slightly elevated soil pH but decreased plant-available soil P, which was, by contrast, lifted by biochar addition. The combined application reduced soil acid-extractable Cr concentration by 40 %. This study provides new insights into comprehensively understanding of the mechanisms of biochar and AM fungi combination on improving plant Cr tolerance.

Contribution of Arbuscular Mycorrhizal Fungi (AMF) in Improving the Growth and Yield Performances of Flax (Linum usitatissimum L.) to Salinity Stress

Throughout the world, salinity is a major environmental issue that limits agricultural productivity, particularly in arid and semi-arid regions. In addition, climate change is the most important reason for the salinization of agricultural soils in the world, so it is now essential to find solutions to increase salinity tolerance in plants. This study investigated the potential of arbuscular mycorrhizal fungi (AMF) inoculation to enhance the growth and yield performances of flax under different salinity levels by conducting a pot experiment. The experiment was laid out in a two-factor completely randomized design including AMF inoculation (AMF+: with inoculation; AMF−: without inoculation) and irrigation water salinity (0, 50, 100, and 150 mM NaCl). According to the results, it is evident that salt stress caused negative physiological effects, including limited growth, reduced photosynthesis, and decreased nitrogen (N) and phosphorus (P) content in the shoots and roots of flax plants. Moreover, mycorrhizal association improved the salt tolerance of the plants by increasing chlorophyll content, and enhancing N and P shoot and root contents and consequently yield parameters, such as seed and stem fiber yield, particularly at moderate salt concentrations (50 and 100 mM NaCl). In particular, under 100 mM, AMF increased the total chlorophyll content, N shoot and root content, P shoot and root content, and seed and stem fiber yield by 30.4%, 36.1%, 31.0%, 38.9%, 45.4%, 35.2%, and 26.9%, respectively. As a result of using AMF, flax plants grown under salt stress exhibited tolerance, suggesting that AMF could be applied in saline environments to maintain ecological stability.

Effects of arbuscular mycorrhizal fungi on plant invasion success driven by nitrogen fluctuations

Abstract Both enemies and mutualists play crucial roles in shaping plant invasion processes. Recent studies have suggested that resource fluctuations could indirectly promote plant invasion through higher trophic levels, such as enemies. However, the influence of mutualists like arbuscular mycorrhizal fungi (AMF) on plant invasion under nitrogen fluctuations remains untested. We conducted a pot mesocosm experiment using a three‐factorial experimental design to assess the individual and interactive effects of nitrogen availability, nitrogen fluctuation and AMF on invasive success of alien plants. We grew nine invasive alien species alongside five different native communities in pot mesocosms. These were then subjected to varied nitrogen availabilities (low vs. high), nitrogen fluctuations (constant vs. pulsed) and AMF presence or absence within a sterile substrate. We found that pulsed nitrogen supply increased the dominance of invasive alien species in low nitrogen availability, regardless of the presence or absence of AMF inoculation. However, in high nitrogen availability, pulsed nitrogen supply only enhanced this dominance in pots without AMF inoculation. This was tentatively evidenced by the three‐way interaction among nitrogen‐availability, nitrogen‐fluctuation and AMF‐inoculation treatments. Furthermore, the dominance promotion by nitrogen addition was greater than that by AMF inoculation. Synthesis and applications. Our findings present, for the first time, evidence that AMF may play a crucial role in mediating the promotion effects of nitrogen fluctuations on alien plant invasion. To better understand the invasion process of alien plants and evaluate their impact on native communities, future research should integrate abiotic and biotic drivers into a single framework. Furthermore, our findings underscore the importance of prioritizing habitats with higher nutrient availability and variability for protection against alien plant invasions.

Arbuscular mycorrhizae increase but vermicompost decrease the sun protection factor (SPF) in leaves of Hymenaea martiana Hayne seedlings

This study aimed to select the most efficient combination of arbuscular mycorrhizal fungi (AMF) and substrate to increase the photoprotective and in vitro antioxidant activities in Hymenaea martiana Hayne leaves. Hymenaea martiana seedlings were grown in soil with or without 10% vermicompost and inoculated with three AMF species: Acaulospora longula, Gigaspora albida, and Claroideoglomus etunicatum. Seedlings grown in soil without vermicompost or AMF inoculation served as controls. After 148 days of growth in a greenhouse, the photoprotective and antioxidant activities, and the production of some phenolics in the leaves were evaluated. Vermicompost supplementation reduced the photoprotective and antioxidant effects in extracts compared to the control. However regardless of the vermicompost treatment, mycorrhizal colonization resulted in a 40% increase in photoprotective activity compared to control; this enhancement was correlated with the increased concentration of proanthocyanidins in mycorrhizal plants. AMF inoculation improves the quality of H. martiana phytomass, dispensing the application of vermicompost in the cultivation substrate. This is the first report on the potential of AMF and vermicompost to increase the sun protection factor in H. martiana leaves.

Morphological and Molecular Characterizations of Arbuscular Mycorrhizal Fungi and Their Influence on Soil Physicochemical Properties and Plant Nutrition.

Pulses are considered a remarkable and stable source of nutrients, which are being presently extensively cultivated and consumed in different parts of the world. Pulses belong to the family Leguminosae and are a rich source of nutrients such as phosphorus (P) and nitrogen (N) for best growth via symbiotic relationship with bacteria and AMF (arbuscular mycorrhizal fungi). The aim of the current study was evaluating the influence of AMF diversity associated with various pulses (French bean, mung bean, kidney bean, peas, soybean, peanuts, and grams). Furthermore, AMF characterization was done using morphological features of spores and sequencing of the rDNA gene, which confirmed the existence of 10 different AMF taxa. Among the different genera, the genus Glomus was observed to be the most dominant with 30% species followed by Gigaspora (22%), Sclerocystis (12%), Acaulospora (8%), Rhizophagus and Septoglomus (7%), Diversispora (5%), and Claroideoglomus, Archaeospora, and Ambispora (3%). Furthermore, soil physicochemical analysis and percentage of AMF colonization results revealed the fact that the phosphorus content (inversely proportional to the AMF diversity) was a determining factor of AMF diversity. The highest amount of available phosphorus (62.825 mg kg-1) in the district Swabi resulted in a low rate of AMF colonization (6.66 ± 11.54%) with a comparatively higher rate of AMF colonization (50.66 ± 1.15%) found in the soil of the district Chitral having a low phosphorus content (17.3 ± 7.6 mg kg-1). Nutrient uptake by pulses including nitrogen (2.4 ± 1.3%), phosphorus (13.5 ± 7.6 mg kg -1), potassium (99.5 ± 25.8 mg kg -1), zinc (1.4 ± 0.5 mg kg -1), moisture (2.3 ± 1.3%), crude fats (5.6 ± 2.8%), ash (4 ± 1.2%), and proteins (13.6 ± 9.01%) determined the fact that AMF species diversity is positively correlated to the plant mineral nutrition. From the current study, it is concluded that AMF inoculation to the soil fields is beneficial to ensure the sustainability and productivity of pulse crops in diverse environmental conditions without polluting the soil.

Arbuscular Mycorrhizal Fungus Funneliformis mosseae Improves Soybean Growth Even in Soils with Good Nutrition

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused on utilizing the prevalent AMF species, Funneliformis mosseae, to enhance Glycine max production, while also exploring its partly explored impact on soil aggregation. Working in greenhouse conditions, we examined whether, in a nutrient-sufficient environment, AMF would improve crop biomass accumulation and nutrition, as well as the stability of soil aggregates (SAS). We also looked for a synergistic effect of dual inoculation using AMF and symbiotic rhizobium. Plants were or were not inoculated with AMF or Bradyrhizobium japonicum in a two-factorial design. AMF inoculation increased soybean biomass, but AMF inoculation had no impact on P and N input to the shoots. Mycorrhiza did not affect either glomalin abundance or SAS. All the impacts were, however, independent from rhizobial inoculation, which was ineffective in this nutrient-available environment. Our assay suggests that arbuscular mycorrhiza may have a positive effect on soybean growth even under conventional management with adequate nutrition. The positive effects of AMF on soybean growth, together with the fact that AMF generally do not thrive in good nutrient availability, should be taken into account when planning mineral fertilization levels.

Efektivitas Fungi Mikoriza Arbuskula yang Diproduksi dengan Teknik Fortifikasi Nutrisi Berbeda terhadap Produktivitas Stylosanthes guianensis pada Cekaman Kekeringan

This study aimed to test the effectiveness of arbuscular mycorrhizal fungi (AMF) products against stylo plants (Stylosanthes guianensis) under drought stress conditions. The research design used a factorial complete random pattern (CRD) with 2 factors. Factor A was AMF: F0 (control), FU (superior AMF as a comparison), FIPB1 (1000ppm ABmix nutrient fortification technique), FIPB2 (2000ppm ABmix nutrient fortification technique), FIPB3 (3000ppm ABmix nutrient fortification technique). Factor B was the drought level, 100% field capacity (FC), 60% FC (medium dry level), and 40% FC (high dry level). The fertilizer for control plants (without AMF) was 100% dose, while plants with AMF were given a 50% dose, adding AMF ± 20 grams. The results showed an interaction between the drought factor and the different types of AMF. AMF was effective in symbiosis with stylo plants at all levels of drought. FIPB1 and FIPB2 could increase plant adaptation up to 60% FC. All AMF inoculations effectively increased leaf chlorophyll content at all drought levels. Biomass accumulation in FU and FIPB1 plants produced the best biomass. The research concluded that the quality of AMF produced with different nutrient fortifications were as good as the superior AMF (FU). Inoculation of AMF products (IPB1, IPB2, and IPB3) with 50% fertilization effectively increased the adaptation and production of Stylosanthes guianensis to a drought level of 60% FC compared to control (without AMF, 100% fertilization).
 Key words: Arbuscular mycorrhizal fungi, drought level, productivity, Stylosanthes guianensis

Effect of arbuscular mycorrhizal fungi on early growth, root colonization, and chlorophyll content of North Maluku nutmeg cultivars

Abstract This study aimed to investigate the agronomic traits of nutmeg transplanting by arbuscular mycorrhizal fungi (AMF) inoculation. The low-fertility soil of Sofifi North Maluku was subjected to a slow early growth stage of nutmeg cultivars. A completely randomized design was used in the experiment. The first factor was three different AMF doses: 0, 4, and 8 g seedlings−1. The second factor consisted of three cultivars: “Ternate 1,” “Tobelo 1,” and “Makian.” Root colonization and agronomic traits were measured 28 weeks after inoculation and transplantation. Results showed that AMF inoculation increased the AM colonization by 2.5–39.0%, significantly increased the leaf area (LA) (p < 0.01) in all cultivars, and interacted with cultivars to increase chlorophyll a (Chl a) (p < 0.05), chlorophyll b (Chl b) (p < 0.01), and total Chl (p < 0.01). Cultivars “Makian” showed the highest Chl (188.4%) at 8 g seedling−1 doses of AMF that were significantly (p < 0.01) different from the cultivar “Tobelo 1” at the same dose. The largest mycorrhizal response was found in the cultivar “Ternate 1” (biomass increase of 30–37.0%). The cultivar “Ternate 1” produced the largest LA (36.7–106.9%) and shoot dry weight (27.8–45.8%) that were significantly (p < 0.01) different from the other cultivars. The percentage of AM colonization was strongly determined (R 2 = 0.88) by Chl a, Chl b, and K content in leaves. This technology is a breakthrough to increase LA and plant biomass in the early growth stage of nutmeg cultivation.

Effects of arbuscular mycorrhizal fungi inoculation on infection and growth of rice and pearl millet in upland fields with three water regimes

ABSTRACT Inoculation with arbuscular mycorrhizal fungi (AMF) may enhance crop growth in upland fields, depending on the water regime. To quantify changes in AMF infection rate and subsequent effects on nutrient uptake and growth, we grew rice (wetland crop) and pearl millet (dryland crop) genotypes with or without the commercial inoculant Dr. Kinkon (Glomus sp. R10) in Andosol upland fields in 2020 and 2021. Root infection rates were measured in shallow (0–10 cm) and deep (20–30 cm) layers under three water regimes: well-irrigated, half-irrigated, and non-irrigated. Inoculation enhanced shoot dry weight (SDW), plant height, tiller number, phosphorus (P) uptake, leaf water potential, photosynthetic rate (measured only in 2021) and root transversal area. The increase in SDW with inoculation was higher under well-irrigated than under water-limited conditions. The increment in pearl millet SDW was related to higher P uptake associated with higher infection rates, whereas that in rice SDW was related to maintenance of leaf water potential, greater root transversal area and root length density, and higher P uptake but not to infection rate parameters. Inoculation increased mycorrhizal and vesicular infection rates with the similar tendency for arbuscular infection rate and qPCR. Infection rates were similar across water regimes in both years despite significant differences in plant growth parameters with higher rates in deep than shallow layers. AMF inoculation enhanced infection rates, mostly independent of water regime, but plant growth enhancement was greater under the well-irrigated treatment and was more directly linked with infection rates in pearl millet.

Mycorrhizal Fungi Reclamation Promotes Stoichiometric Homeostasis of Re-Vegetation Types and Affects Soil Bacterial Function in Mining Subsidence of Northern Loess Plateau

Re-vegetation types and mycorrhizal fungi reclamation play a vital role in the improvement of soil quality in the mining subsidence of the northern Loess Plateau. However, the effects of re-vegetation types and mycorrhizal fungi reclamation on plant stoichiometric homeostasis, soil bacterial communities and functional characteristics are still not understood well but are vital for mining green construction. Based on the fact that mycorrhizal fungi reclamation has been implemented for more than 10 years (inoculation with arbuscular mycorrhizal fungi (AMF) and control), we examined five re-vegetation types with different C:N:P stoichiometry in the roots, leaves and calculated homeostasis. Meanwhile, second-generation sequencing technology was used to measure soil bacterial communities and functional characteristics to further reveal the relationships between soil factors and bacteria that drive plant stoichiometry and homeostasis in the biological reclamation area of coal mining subsidence. Our results indicated that plant N:P ratio in the leaves of all re-vegetation types was less than 14, with the highest ratio observed in A. fruticosa (nitrogen-fixing plants), showing that re-vegetation growth was limited by the availability of nitrogen. Only leaves in AMF-inoculated plants were categorized as ‘homeostatic’, while inoculation with AMF in both leaves and roots could alleviate nitrogen restriction and improve ecological stoichiometric homeostasis. The dominant phylum was Proteobacteria, followed by Actinobacteria, Acidobacteria, accounting for 69.92%–73.22% of all bacterial species and 82% with Chloroflexi. Soil copiotrophic community (Proteobacteria) in the AMF inoculation area was higher than those in the control area under all re-vegetation types, while the oligotrophic community (Acidobacteria) was lower than the control. Further analysis showed that soil TP, SOC, C:N and HD played vital roles in shifting the soil bacteria community. Soil stoichiometry and AMF affect microbial composition. These results indicated that the re-vegetation types and mycorrhizal fungi reclamation could shift bacterial homogeneity. Hence, our results expound that mycorrhizal fungi reclamation could optimize the ecological strategies of reclaimed vegetation, alleviate N-limitations in plants, improve endogenous stability and promote the ecological function of soil bacteria, which provided theoretical bases for further understanding and application of green restoration and sustainable development in the mining subsidence of the northern Loess Plateau.

Arbuscular Mycorrhizae Alter Photosynthetic Responses to Drought in Seedlings of Artemisia tridentata.

The establishment of Artemisia tridentata, a keystone species of the sagebrush steppe, is often limited by summer drought. Symbioses with arbuscular mycorrhizal fungi (AMF) can help plants to cope with drought. We investigated this possible effect on A. tridentata seedlings inoculated with native AMF and exposed to drought in greenhouse and field settings. In greenhouse experiments, AMF colonization increased intrinsic water use efficiency under water stress and delayed the decrease in photosynthesis caused by drought, or this decrease occurred at a lower soil water content. In the field, we evaluated the effect of AMF inoculation on colonization, leaf water potential, survival, and inflorescence development. Inoculation increased AMF colonization, and the seedlings experienced water stress, as evidenced by water potentials between -2 and -4 MPa and reduced stomatal conductance. However, survival remained high, and no differences in water potentials or survival occurred between treatments. Only the percentage of plants with inflorescence was higher in inoculated than non-inoculated seedlings. Overall, the greenhouse results support that AMF colonization enhances drought tolerance in A. tridentata seedlings. Yet, the significance of these results in increasing survival in nature remains to be tested under more severe drought than the plants experienced in our field experiment.

Unravelling the Combined Use of Soil and Microbial Technologies to Optimize Cultivation of Halophyte Limonium algarvense (Plumbaginaceae) Using Saline Soils and Water

Salt-affected soils have detrimental effects on agriculture and ecosystems. However, these soils can still be used for halophyte (salt-tolerant plants) cultivation using brackish and/or saline water. In this study, we employed soil technologies and mutualistic microorganisms as a sustainable strategy to improve the growth and reproduction of the halophyte Limonium algarvense Erben’s growth and reproduction under saline conditions. A microcosm assay was conducted under controlled greenhouse conditions to cultivate L. algarvense using a saline Fluvisol (FLU) amended—or not—with a Technosol (TEC). Plants were inoculated with the arbuscular mycorrhizal fungus (AMF) Rhizoglomus irregulare and/or a consortium of plant growth-promoting bacteria (PGPB), and they were irrigated with estuarine water. Soil enzyme analysis and physicochemical characterisation of the soils, collected at the beginning and at the end of the assay, were carried out. The physiological status of non-inoculated and inoculated plants was monitored during the assay for 4 months, and AMF root colonisation was evaluated. In FLU, only plants inoculated with the AMF survived. These plants had lower number of leaves, and shoot and root dry biomass than the ones grown in the TEC by the end of the assay. In the TEC, PGPB inoculation led to higher NDVI and PRI values, and AMF inoculation promoted higher reproductive development but not pollen fertility. The findings show that the combined use of soil and microbial technologies can be successfully applied to cultivate L. algarvense, suggesting their generalized use for other Limonium species with economic interest, while contributing to the sustainable use of marginal lands.

Mycorrhizal Fungal Effects on Plant Growth, Osmolytes, and CsHsp70s and CsPIPs Expression in Leaves of Cucumber under a Short-Term Heat Stress.

Arbuscular mycorrhizal (AM) fungi enhance plant stress tolerance, but it is unclear whether AM fungi affect heat tolerance in cucumbers. This study aimed to analyze how an AM fungus, Diversispora versiformis, affected growth, chlorophyll, five osmolytes, and plasma membrane intrinsic proteins (PIPs) and heat shock protein 70 (Hsp70) gene expression in cucumber leaves after a short-term (80 h) heat stress. Heat treatment significantly reduced root AM fungal colonization rate (0.26 folds). Heat treatment also distinctly suppressed plant height, stem diameter, and biomass, whereas AM fungal inoculation improved these growth variables as well as the chlorophyll index, with the benefit being more obvious under heat than under no-heat stress conditions. Heat treatment triggered differential changes in osmolytes (sucrose, fructose, and betaine) of inoculated and uninoculated cucumbers, whereas inoculation with AM fungus significantly raised leaf sucrose, fructose, glucose, betaine, and proline levels when compared to non-AM fungal inoculation. Heat treatment increased the expression of two (CsPIP1;6 and CsPIP2;1) of eight CsPIPs in inoculated and uninoculated plants, whereas AM fungal inoculation up-regulated the expression of CsPIP1;6, CsPIP2;1, and CsPIP2;6 under heat stress conditions. Hsp70s expressed differently in inoculated and uninoculated plants under heat versus no-heat stress, with 6 of 11 CsHsp70s down-regulated in inoculated plants. Under heat stress conditions, AM fungus only up-regulated CsHsp70-8 expression in 11 Hsp70s, while another eight CsHsp70s were down-regulated. Heat treatment and AM fungal inoculation both increased the expression of CsHsp70-8 and CsPIP1;6. It was concluded that AM fungus-inoculated cucumbers have high levels of growth, chlorophyll, and osmolytes under heat stress and do not require high CsPIPs and CsHsp70s expression to tolerate a short-term heat treatment.

Pigeon Pea (Cajanus cajan L.) Based Intercropping System: A Review

Pigeon pea (Cajanus cajan L.) is a tropical and subtropical leguminous crop it is rich in protein and has high nutrient content and India is the largest producer. Pigeon pea is grown in a sole cropping system as well as with intercropping system it is majorly intercropped with legumes, cereal, and oilseed crops. Intercropping depends upon the interaction of crop species and their management. Intercropping is done between different types of cereals, pulses, and oilseed crops. Some successful cereal and pulse intercropping systems like (mung bean + maize) where, a larger equivalent yield is obtained by seeding maize following four rows of mung beans than by closer spacing. Wheat is mostly intercropped with chickpea, mustard and barley but in irrigated conditions when wheat intercropped with mustard proved more profitable than wheat intercropped with chickpea. In the Mediterranean nation, common vetch (Vicia sativa) is popularly grown with cereals. When maize and cowpea were intercropped in southern Africa, the quantity of nitrogen, phosphate, and potassium in the soil was enhanced. Maize and beans are popular in eastern Africa. However, there are many challenges while adopting intercropping for the survival of the plant. In intercropping of pigeon pea when two or more than crops are sown, they show a synergetic effect, and when it is treated with the biofertilizers like Rhizobium, arbuscular mycorrhizal fungi (AMF), phosphate-solubilizing microorganisms (PSM) and plant growth-promoting rhizobacteria (PGPR), it enhances the growth of the plant, fixes atmospheric nitrogen in the soil, availability of phosphorus to the plant increases the uptake of other micro-nutrient to the plant and plant beneficial microbes. When dual inoculation of Rhizobium and AMF is done, chlorophyll content increases in the plant.

Arbuscular Mycorrhizal Fungi Enhance Drought Stress Tolerance by Regulating Osmotic Balance, the Antioxidant System, and the Expression of Drought-Responsive Genes in Vitis vinifera L.

Background and Aims. Drought harms the growth and productivity of grapevines; it thus poses a major threat to the development of viticulture in the background of ongoing climate change. Arbuscular mycorrhizal fungi (AMF) can be used to enhance the resistance/tolerance of plants to environmental stress. The effects of AMF on the osmotic regulation, antioxidant substances, and expression of drought-responsive genes in the grapevine Vitis vinifera L. cv. Ecolly were studied. Methods and Results. The experiment was conducted in a greenhouse in a completely randomized block design with four treatments: AMF colonization, well-watered; non-AMF colonization, well-watered; AMF colonization with drought stress; and non-AMF colonization with drought stress. The concentration of sucrose and proline in the leaves was higher in mycorrhizal grapevine than in nonmycorrhizal grapevine under drought stress. The concentration of malonaldehyde, hydrogen peroxide, superoxide anion, and glutathione and the activity of superoxide dismutase and peroxidase activity in leaves were higher in mycorrhizal grapevine than in nonmycorrhizal grapevine under drought conditions. AMF inoculation affected the expression of drought-responsive genes. Mycorrhization upregulated the expression of VvNCED, VvP5CS, VvSIP, VvPIP1;2, and VvTIP2;1 genes under drought stress. Conclusions. AMF could reduce the harm caused by drought stress by regulating osmosis, antioxidant activities, and the expression of key drought-responsive genes and aquaporin genes. Significance of the Study. This work provides insights into the physiological and biochemical activities influenced by AMF on grapevine under drought stress.

Crop Productivity Boosters: Native Mycorrhizal Fungi from an Old-Growth Grassland Benefits Tomato (Solanum lycopersicum) and Pepper (Capsicum annuum) Varieties in Organically Farmed Soils.

This paper investigates the response of five tomato and five pepper varieties to native arbuscular mycorrhizal (AM) fungal inoculation in an organic farming system. The field experiment was conducted across a growing season at a working organic farm in Lawrence, KS, USA. The researchers hypothesized that native AM fungi inoculation would improve crop biomass production for both crop species, but that the magnitude of response would depend on crop cultivar. The results showed that both crops were significantly positively affected by inoculation. AM fungal inoculation consistently improved total pepper biomass throughout the experiment (range of +2% to +8% depending on the harvest date), with a +3.7% improvement at the final harvest for inoculated plants. An interaction between pepper variety and inoculation treatment was sometimes observed, indicating that some pepper varieties were more responsive to AM fungi than others. Beginning at the first harvest, tomatoes showed a consistent positive response to AM fungal inoculation among varieties. Across the experiment, AM fungi-inoculated tomatoes had +10% greater fruit biomass, which was driven by a +20% increase in fruit number. The study highlights the potential benefits of using native AM fungi as a soil amendment in organic farmed soils to improve pepper and tomato productivity.