Zinc nutrition and arbuscular mycorrhizal symbiosis effects on maize (Zea mays L.) growth and productivity

Widely Targeted Metabolomic Analysis Reveals the Improvement in Panax notoginseng Triterpenoids Triggered by Arbuscular Mycorrhizal Fungi via UPLC-ESI-MS/MS

Panax notoginseng is a highly valued perennial medicinal herb in China and is widely used in clinical treatments. The main purpose of this study was to elucidate the changes in the composition of P. notoginseng saponins (PNSs), which are the main bioactive substances, triggered by arbuscular mycorrhizal fungi (AMF) via ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). A total of 202 putative terpenoid metabolites were detected, of which 150 triterpene glycosides were identified, accounting for 74.26% of the total. Correlation analysis, principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) of the metabolites revealed that the samples treated with AMF (group Ce) could be clearly separated from the CK samples. In total, 49 differential terpene metabolites were identified between the Ce and CK groups, of which 38 and 11 metabolites were upregulated and downregulated, respectively, and most of the upregulated differentially abundant metabolites were mainly triterpene glycosides. The relative abundances of the two major notoginsenosides (MNs), ginsenosides Rd and Re, and 13 rare notoginsenosides (RNs), significantly increased. The differential saponins, especially RNs, were more easily clustered into one branch and had a high positive correlation. It could be concluded that the biosynthesis and accumulation of some RNs share the same pathways as those triggered by AMF. This study provides a new way to obtain more notoginsenoside resources, particularly RNs, and sheds new light on the scientization and rationalization of the use of AMF agents in the ecological planting of medicinal plants.

Optimizing water relations, gas exchange parameters, biochemical attributes and yield of water-stressed maize plants through seed priming with iron oxide nanoparticles

Drought poses significant risks to maize cultivation by impairing plant growth, water uptake and yield; nano priming offers a promising avenue to mitigate these effects by enhancing plant water relations, stress tolerance and overall productivity. In the current experiment, we tested a hypothesis that seed priming with iron oxide nanoparticles (n-Fe2O3) can improve maize performance under water stress by improving its growth, water relations, yield and biochemical attributes. The experiment was conducted on a one main plot bisected into two subplots corresponding to the water and drought environments. Within each subplot, maize plants were raised from n-Fe2O3 primed seeds corresponding to 0 mg. L- 1 (as control treatment), 25, 50, 75, and 100 mg. L- 1 (as trial treatments). Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved the leaf relative water content, water potential, photosynthetic water use efficiency, and leaf intrinsic water use efficiency of maize plants by 13%, 44%, 64% and 17%, respectively compared to control under drought stress. The same treatments improved plant biochemical attributes such as total chlorophyll content, total flavonoids and ascorbic acid by 37%, 22%, and 36%, respectively. Seed priming with n-Fe2O3 accelerated the functioning of antioxidant enzymes such as SOD and POD and depressed the levels of leaf malondialdehyde and hydrogen peroxide significantly. Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved cob length, number of kernel rows per cob, and 100 kernel weight by 59%, 27% and 33%, respectively, under drought stress. Seed priming with n-Fe2O3 can be used to increase maize production under limited water scenarios.

Enhancing Agricultural Sustainability Through Rhizomicrobiome: A Review

Sustainable agriculture represents the responsible utilization of natural resources while safeguarding the well-being of the natural environment. It encompasses the objectives of preserving the environment, fostering economic growth, and promoting socioeconomic equality. To achieve sustainable development for humanity, it is imperative to prioritize sustainable agriculture. One significant approach to achieving this transition is the extensive utilization of microbes, which play a crucial role due to the genetic reliance of plants on the beneficial functions provided by symbiotic microbes. This review focuses on the significance of rhizospheric microbial communities, also known as the rhizomicrobiome (RM). It is a complex community of microorganisms that live in the rhizosphere and influence the plant's growth and health. It provides its host plant with various benefits related to plant growth, including biocontrol, biofertilization, phytostimulation, rhizoremediation, stress resistance, and other advantageous properties. Yet, the mechanisms by which the RM contributes to sustainable agriculture remain largely unknown. Investigating this microbial population presents a significant opportunity to advance toward sustainable agriculture. Hence, this study aims to provide an overview of the diversity and applications of RM in sustainable agriculture practices. Lately, there has been growing momentum in various areas related to rhizobiome research and its application in agriculture. This includes rhizosphere engineering, synthetic microbiome application, agent-based modeling of the rhizobiome, and metagenomic studies. So, developing bioformulations of these beneficial microorganisms that support plant growth could serve as a promising solution for future strategies aimed at achieving a new green revolution.

Alleviation of salinity stress by EDTA chelated-biochar and arbuscular mycorrhizal fungi on maize via modulation of antioxidants activity and biochemical attributes

Salinity stress adversely affects agricultural productivity by disrupting water uptake, causing nutrient imbalances, and leading to ion toxicity. Excessive salts in the soil hinder crops root growth and damage cellular functions, reducing photosynthetic capacity and inducing oxidative stress. Stomatal closure further limits carbon dioxide uptake that negatively impact plant growth. To ensure sustainable agriculture in salt-affected regions, it is essential to implement strategies like using biofertilizers (e.g. arbuscular mycorrhizae fungi = AMF) and activated carbon biochar. Both amendments can potentially mitigate the salinity stress by regulating antioxidants, gas exchange attributes and chlorophyll contents. The current study aims to explore the effect of EDTA-chelated biochar (ECB) with and without AMF on maize growth under salinity stress. Five levels of ECB (0, 0.2, 0.4, 0.6 and 0.8%) were applied, with and without AMF. Results showed that 0.8ECB + AMF caused significant enhancement in shoot length (~ 22%), shoot fresh weight (~ 15%), shoot dry weight (~ 51%), root length (~ 46%), root fresh weight (~ 26%), root dry weight (~ 27%) over the control (NoAMF + 0ECB). A significant enhancement in chlorophyll a, chlorophyll b and total chlorophyll content, photosynthetic rate, transpiration rate and stomatal conductance was also observed in the condition 0.8ECB + AMF relative to control (NoAMF + 0ECB), further supporting the efficacy of such a combined treatment. Our results suggest that adding 0.8% ECB in soil with AMF inoculation on maize seeds can enhance maize production in saline soils, possibly via improvement in antioxidant activity, chlorophyll contents, gas exchange and morphological attributes.

Facile biosynthesis, characterisation and biotechnological application of ZnO nanoparticles mediated by leaves of Cnidoscolus aconitifolius

The present study synthesised and characterised zinc oxide nanoparticles (ZnO NPs) using spinach tree, Cnidoscolus aconitifolius and investigated its potential use as nanofertilizer. The synthesised nanoparticles showed UV-Vis absorption peak at 378 nm which is a feature of ZnO NPs. FT-IR analysis further revealed the presence of O-H stretching, C = C bending, O-H bending and C-N stretching functional groups of the stabilising action of the plant extract on the surface of the nanoparticles. SEM images displayed the shape of NPs to be spherical whereas TEM images showed their distribution sizes to be 100 nm. Synthesised ZnO NPs were used as a nano fertilizer on Sorghum bicolour plant. An increase in the shoot leaf length with an average length of 16.13 ± 0.19 cm as compared to the control group of 15.13 ± 0.07 cm was observed. The rate of photosynthesis also showed a significant increase with total chlorophyll content of 0.2806 ± 0.006 mg/mL as compared with control of 0.2476 ± 0.002 mg/mL. The activity of antioxidative enzymes was measured with an increase in the specific activity of SOD in the plant when ZnO NPs were used over NPK whereas, the specific activities of CAT were similar in all cases.

Role of Arbuscular Mycorrhizal Fungi in Regulating Growth, Enhancing Productivity, and Potentially Influencing Ecosystems under Abiotic and Biotic Stresses

Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with the roots of nearly all land-dwelling plants, increasing growth and productivity, especially during abiotic stress. AMF improves plant development by improving nutrient acquisition, such as phosphorus, water, and mineral uptake. AMF improves plant tolerance and resilience to abiotic stressors such as drought, salt, and heavy metal toxicity. These benefits come from the arbuscular mycorrhizal interface, which lets fungal and plant partners exchange nutrients, signalling molecules, and protective chemical compounds. Plants' antioxidant defence systems, osmotic adjustment, and hormone regulation are also affected by AMF infestation. These responses promote plant performance, photosynthetic efficiency, and biomass production in abiotic stress conditions. As a result of its positive effects on soil structure, nutrient cycling, and carbon sequestration, AMF contributes to the maintenance of resilient ecosystems. The effects of AMFs on plant growth and ecological stability are species- and environment-specific. AMF's growth-regulating, productivity-enhancing role in abiotic stress alleviation under abiotic stress is reviewed. More research is needed to understand the molecular mechanisms that drive AMF-plant interactions and their responses to abiotic stresses. AMF triggers plants' morphological, physiological, and molecular responses to abiotic stress. Water and nutrient acquisition, plant development, and abiotic stress tolerance are improved by arbuscular mycorrhizal symbiosis. In plants, AMF colonization modulates antioxidant defense mechanisms, osmotic adjustment, and hormonal regulation. These responses promote plant performance, photosynthetic efficiency, and biomass production in abiotic stress circumstances. AMF-mediated effects are also enhanced by essential oils (EOs), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), hydrogen peroxide (H2O2), malondialdehyde (MDA), and phosphorus (P). Understanding how AMF increases plant adaptation and reduces abiotic stress will help sustain agriculture, ecosystem management, and climate change mitigation. Arbuscular mycorrhizal fungi (AMF) have gained prominence in agriculture due to their multifaceted roles in promoting plant health and productivity. This review delves into how AMF influences plant growth and nutrient absorption, especially under challenging environmental conditions. We further explore the extent to which AMF bolsters plant resilience and growth during stress.

Seed bio-priming with beneficial Trichoderma harzianum alleviates cold stress in maize

Maize is one of the major crops in the world and the most productive member of the Gramineae family. Since cold stress affects the germination, growth, and productivity of corn seeds, the present study aimed to investigate the effect of seed biopriming with Trichoderma harzianum on the tolerance of two genotypes of maize seedlings to cold stress. This study was conducted in triplicates in factorial experiment with a complete randomized block design (CRBD). The study was conducted in the greenhouse and laboratory of the University of Mohaghegh Ardabili, Ardabil, Iran. Experimental factors include two cultivars (AR68 cold-resistant and KSC703 cold-sensitive maize cultivars), four pretreatment levels (control, biopriming with T. harzianum, exogenous T. harzianum, and hydropriming), and two levels of cold stress (control and cold at 5 °C) in a hydroponic culture medium. The present study showed that maize leaves' establishment rate and maximum fluorescence (Fm) are affected by triple effects (C*, P*, S). The highest establishment (99.66%) and Fm (994 units) rates were observed in the KP3 control treatment. Moreover, among the pretreatments, the highest (0.476 days) and the lowest (0.182 days) establishment rates were related to P0 and P3 treatments, respectively. Cultivar A showed higher chlorophyll a and b, carotenoid content, and establishment rate compared to cultivar K in both optimal and cold conditions. The highest root dry weight (11.84 units) was obtained in cultivar A with P3 pretreatment. The pretreatments with T. harzianum increased physiological parameters and seedling emergence of maize under cold and optimal stress conditions. Pretreatment and cultivar improved catalase activity in roots and leaves. Higher leaf and root catalase activity was observed in the roots and leaves of cultivar K compared to cultivar A. The cold treatment significantly differed in peroxidase activity from the control treatment. Cultivar K showed higher catalase activity than cultivar A. The main effects of pretreatment and cold on polyphenol oxidase activity and proline content showed the highest polyphenol oxidase activity and proline content in hydropriming (H) treatment. Cold treatment also showed higher polyphenol oxidase activity and proline content than cold-free conditions.

Deciphering the functional roles of transporter proteins in subcellular metal transportation of plants

MAIN CONCLUSION

The role of transporters in subcellular metal transport is of great significance for plants in coping with heavy metal stress and maintaining their proper growth and development. Heavy metal toxicity is a serious long-term threat to plant growth and agricultural production, becoming a global environmental concern. Excessive heavy metal accumulation not only damages the biochemical and physiological functions of plants but also causes chronic health hazard to human beings through the food chain. To deal with heavy metal stress, plants have evolved a series of elaborate mechanisms, especially a variety of spatially distributed transporters, to strictly regulate heavy metal uptake and distribution. Deciphering the subcellular role of transporter proteins in controlling metal absorption, transport and separation is of great significance for understanding how plants cope with heavy metal stress and improving their adaptability to environmental changes. Hence, we herein introduce the detrimental effects of excessive common essential and non-essential heavy metals on plant growth, and describe the structural and functional characteristics of transporter family members, with a particular emphasis on their roles in maintaining heavy metal homeostasis in various organelles. Besides, we discuss the potential of controlling transporter gene expression by transgenic approaches in response to heavy metal stress. This review will be valuable to researchers and breeders for enhancing plant tolerance to heavy metal contamination.

Co-inoculation of Mycorrhiza and methyl jasmonate regulates morpho-physiological and antioxidant responses of Crocus sativus (Saffron) under salinity stress conditions

Salinity stress is the second most devastating abiotic factor limiting plant growth and yields. Climate changes have significantly increased salinity levels of soil. Besides improving the physiological responses under stress conditions, jasmonates modulate Mycorrhiza-Plant relationships. The present study aimed to evaluate the effects of methyl jasmonate (MeJ) and Funneliformis mosseae (Arbuscular mycorrhizal (AM) on morphology and improving antioxidant mechanisms in Crocus sativus L. under salinity stress. After inoculation with AM, pre-treated C. sativus corms with MeJ were grown under low, moderate, and severe salinity stress. Intense salinity levels damaged the corm, root, total leaf dry weight, and area. Salinities up to 50 mM increased Proline content and Polyphenol oxidase (PPO) activity, but MeJ increased this trend in proline. Generally, MeJ increased anthocyanins, total soluble sugars, and PPO. Total chlorophyll and superoxide dismutase (SOD) activity increased by salinity. The maximum catalase and SOD activities in + MeJ + AM were 50 and 125 mM, respectively, and the maximum total chlorophyll in -MeJ + AM treatment was 75 mM. Although 20 and 50 mM increased plant growth, using mycorrhiza and jasmonate enhanced this trend. Moreover, these treatments reduced the damage of 75 and 100 mM salinity stress. Using MeJ and AM can improve the growth of saffron under various ranges of salinity stress levels; however, in severe levels like 120 mM, this phytohormone and F. mosseae effects on saffron could be adverse.

Zn Fertilizer and Mycorrhizal Inoculation Effect on Bread Wheat Cultivar Grown under Water Deficit

During drought stress, many enzymes are inactivated in plants due to Zn deficiency. Zn application and arbuscular mycorrhiza fungi (AMF)-wheat symbiosis reportedly improve the tolerance of plants to drought stress. This study was done to investigate the effect of Zn and AMF on plant growth, yield attributes, relative water content (RWC), harvest index (HI), photosynthetic activity, solute accumulation, glycine betaine (GB) accumulation, antioxidant activities [(catalase (CAT) and superoxide dismutase (SOD)], and ionic attributes in a bread wheat cultivar (SST806) under drought-stress in plants grown under greenhouse conditions. Zn application and AMF inoculation, separately and combined, enhanced all plant growth parameters and yield. Root dry weight (RDW) was increased by 25, 30, and 46% for these three treatments, respectively, under drought conditions compared to the control treatment. Overall, Zn application, AMF inoculation, and their combination increased protein content, RWC, and harvest index (HI) under drought stress. However, AMF inoculation improved proline content more than Zn application under the same conditions. Regarding GB accumulation, AMF, Zn, and the combination of Zn and AMF increased GB under drought compared to well-watered conditions by 31.71, 10.36, and 70.70%, respectively. For the antioxidant defense, AMF inoculation and Zn application improved SOD and CAT activity by 58 and 56%, respectively. This study showed that Zn and/or AMF increased antioxidant levels and ionic attributes under abiotic stress.

Analysis of the molecular and biochemical mechanisms involved in the symbiotic relationship between Arbuscular mycorrhiza fungi and Manihot esculenta Crantz

INTRODUCTION

Plants and arbuscular mycorrhizal fungi (AMF) mutualistic interactions are essential for sustainable agriculture production. Although it is shown that AMF inoculation improves cassava physiological performances and yield traits, the molecular mechanisms involved in AM symbiosis remain largely unknown. Herein, we integrated metabolomics and transcriptomics analyses of symbiotic (Ri) and asymbiotic (CK) cassava roots and explored AM-induced biochemical and transcriptional changes.

RESULTS

Three weeks (3w) after AMF inoculations, proliferating fungal hyphae were observable, and plant height and root length were significantly increased. In total, we identified 1,016 metabolites, of which 25 were differentially accumulated (DAMs) at 3w. The most highly induced metabolites were 5-aminolevulinic acid, L-glutamic acid, and lysoPC 18:2. Transcriptome analysis identified 693 and 6,481 differentially expressed genes (DEGs) in the comparison between CK (3w) against Ri at 3w and 6w, respectively. Functional enrichment analyses of DAMs and DEGs unveiled transport, amino acids and sugar metabolisms, biosynthesis of secondary metabolites, plant hormone signal transduction, phenylpropanoid biosynthesis, and plant-pathogen interactions as the most differentially regulated pathways. Potential candidate genes, including nitrogen and phosphate transporters, transcription factors, phytohormone, sugar metabolism-related, and SYM (symbiosis) signaling pathway-related, were identified for future functional studies.

DISCUSSION

Our results provide molecular insights into AM symbiosis and valuable resources for improving cassava production.

Piper caninum extract and Brevibacillus agri mixture suppresses rice leaf spot pathogen; Nigrospora oryzae and improves the production of red rice (Oryza sativa L)

Under the guise of enhancing productivity, using pesticides and artificial fertilizers in agriculture affects both the environment and living things. High chemical residues in food and the environment disrupt the health of consumers. One of the solutions that can bring about a reduction in the use of pesticides and chemicals is switching to organic fertilizers. The application of biopesticides originating from biological sources such as plant extracts and the use of microbes is gaining global acceptance. Therefore, this study aimed to obtain the best biopesticides and biostimulants that could suppress the leaf spot pathogen, Nigrospora oryzae, and increase the growth and yield of Bali red rice. The study contained four treatments, namely untreated control (F0), Piper caninum leaf extract (F1), Brevibacillus agri (F2), and fermented P. caninum leaf extract plus B. agri (F3). The treatments were arranged in a randomized complete block design, and each treatment was replicated three times. The parameters measured were the number of tillers per plant, number of leafs per plant, chlorophyll content, number of grains per panicle, grain weight, and grain yield. Furthermore, antimicrobial and antioxidants were assayed using SEM. GC-MS. At the end of the experiment, the disease index of the leaf spot was measured. The results showed that F3 significantly suppressed leaf spots caused by N. oryzae compared to other treatments, including untreated control in red rice. Additionally, the F3 significantly increased the number of productive tillers, number of grains per panicle, and grain yield compared to all other treatments. The F3 enhanced the crop yield at 6.19 tons/ha, an increase of 50% compared to the untreated control. The SEM.GC-MS results showed the presence of 2.3 butanediol, tetra-decanoic acid, butanoic acid, ethyl ester, benzene propanal, 3-(1,1-dimethylethyl)-a-methyl, a-N-Normethadol in treated plants with P. canicum plus B. agri.

Azospirillum brasilense and Zinc Rates Effect on Fungal Root Colonization and Yield of Wheat-Maize in Tropical Savannah Conditions

A successful microbial inoculant can increase root colonization and establish a positive interaction with native microorganisms to promote growth and productivity of cereal crops. Zinc (Zn) is an intensively reported deficient nutrient for maize and wheat production in Brazilian Cerrado. It can be sustainably managed by inoculation with plant growth-promoting bacteria and their symbiotic association with other microorganisms such as arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE). The objective of this study was to evaluate the effect of Azospirillum brasilense inoculation and residual Zn rates on root colonization and grain yield of maize and wheat in succession under the tropical conditions of Brazil. These experiments were conducted in a randomized block design with four replications and arranged in a 5 × 2 factorial scheme. The treatments consisted of five Zn rates (0, 2, 4, 6 and 8 kg ha^-1) applied from zinc sulfate in maize and residual on wheat and without and with seed inoculation of A. brasilense. The results indicated that root colonization by AMF and DSE in maize-wheat cropping system were significantly increased with interaction of Zn rates and inoculation treatments. Inoculation with A. brasilense at residual Zn rates of 4 kg ha^-1 increased root colonization by AMF under maize cultivation. Similarly, inoculation with A. brasilense at residual Zn rates of 2 and 4 kg ha^-1 reduced root colonization by DSE under wheat in succession. The leaf chlorophyll index and leaf Zn concentration were increased with inoculation of the A. brasilense and residual Zn rates. The inoculation did not influence AMF spore production and CO₂-C in both crops. The grain yield and yield components of maize-wheat were increased with the inoculation of A. brasilense under residual Zn rates of 3 to 4 kg ha^-1 in tropical savannah conditions. Inoculation with A. brasilense under residual Zn rates up to 4 kg ha^-1 promoted root colonization by AMF and DSE in the maize cropping season. While the inoculation with A. brasilense under 2 and 4 kg ha^-1 residual Zn rates reduced root colonization by AMF and DSE in the wheat cropping season. Therefore, inoculation with A. brasilense in combination with Zn fertilization could consider a sustainable approach to increase the yield and performance of the maize-wheat cropping system in the tropical savannah conditions of Brazil.

Is the Arbuscular Mycorrhizal Fungus Funneliformis mosseae a Suitable Agent to Control Criconematid Populations?

Several studies have shown the potential of using mycorrhizal fungi in increasing the plant yield by simultaneously reducing damages caused by pathogens. Plant parasitic nematodes (PPNs) are among the most feared pathogens for crops. This study aimed to evaluate the effects of Funneliformis mosseae as a mycorrhizal fungus on the population abundance of three world widespread species of nematodes from the family Criconematidae: Mesocriconema xenoplax, Mesocriconema antipolitanum, and Criconemides informis. Pure and highly abundant populations of each species were collected from Urmia city in Northwestern Iran, after the identification morphological and morphometric characteristics. The experiments were carried out in greenhouse conditions on three different rhizospheres of alfalfa, sugar beet, and wheat. After five months, the final population of nematodes and fungus, and the root surface on host plants inoculated and non-inoculated with the fungus F. mosseae, were evaluated. The results showed that the population of nematodes was increased in the presence of the fungus. It could be assumed that the extension of the host surface level of roots by the fungus resulted in more feeding sites for nematode activity and, consequently, higher population densities. In this study, the fungus did not seem to play a suitable role in controlling ectoparasitic nematode growth. However, since there are still many open questions about mycorrhizal fungi’s role in agriculture, more research should be conducted.

Co-inoculation of biochar and arbuscular mycorrhizae for growth promotion and nutrient fortification in soybean under drought conditions

Drought is significant abiotic stress that affects the development and yield of many crops. The present study is to investigate the effect of arbuscular mycorrhizal fungi (AMF) and biochar on root morphological traits, growth, and physiological traits in soybean under water stress. Impact of AMF and biochar on development and root morphological traits in soybean and AMF spores number and the soil enzymes' activities were studied under drought conditions. After 40 days, plant growth parameters were measured. Drought stress negatively affected soybean growth, root parameters, physiological traits, microbial biomass, and soil enzyme activities. Biochar and AMF individually increase significantly plant growth (plant height, root dry weight, and nodule number), root parameters such as root diameter, root surface area, total root length, root volume, and projected area, total chlorophyll content, and nitrogen content in soybean over to control in water stress. In drought conditions, dual applications of AMF and biochar significantly enhanced shoot and root growth parameters, total chlorophyll, and nitrogen contents in soybean than control. Combined with biochar and AMF positively affects AMF spores number, microbial biomass, and soil enzyme activities in water stress conditions. In drought stress, dual applications of biochar and AMF increase microbial biomass by 28.3%, AMF spores number by 52.0%, alkaline phosphomonoesterase by 45.9%, dehydrogenase by 46.5%, and fluorescein diacetate by 52.2%, activities. The combined application of biochar and AMF enhance growth, root parameters in soybean and soil enzyme activities, and water stress tolerance. Dual applications with biochar and AMF benefit soybean cultivation under water stress conditions.

Sole and combined effect of foliar zinc and arbuscular mycorrhizae inoculation on basmati rice growth, productivity and grains nutrient

Mismanagement in foliar fertilizer application at different crop stages decreases the productivity of the crop. Likewise, higher application of phosphorus (P) beyond recommended application rates not only decrease zinc (Zn) uptake in rice but also increase fertilizer use cost. Inoculation of arbuscular mycorrhizae (AMF) may optimize the uptake of P and improve crops production via organic secretions. That’s why the current study was conducted to examine the individual and coordinated effects of 0.5% Zn (0.5Zn) foliar spray (tillering (T) and/or panicle (P) initiation stage) and AMF application. Application of foliar 0.5Zn at tillering+panicle stage remained significantly better for significant enhancement in plant height, spike length, gas exchange attributes and total chlorophyll contents than control. A significant decrease in electrolyte leakage Also validated the effectiveness of treatment 0.5ZnT+P compared to control. Compared to control, the maximum increase in N (14.5 and 25.7%), P (42.1 and 33.3%), K (22.2 and 30.0%) and Zn (19.3 and 27.8%) accumulation was also found in 0.5ZnT+P, with and without AMF, respectively. In conclusion, 0.5ZnT+P with AMF is a better approach than sole application of Zn at tillering or panicle initiation stages. Nevertheless, more investigations are suggested at field level under variable climatic zones to confirm the effectiveness of 0.5ZnT+P with AMF for improvement in rice growth and production.

Prevalence of mycorrhizae in host plants and rhizosphere soil: A biodiversity aspect

Plants roots are colonized by soil inhabitants known as arbuscular mycorrhizal fungi (AMF), which increase plant productivity, and enhance carbon storage in the soil. We found mycorrhizal vesicles, arbuscles, and mycelium in the root of more than 89% of the selected plants of University of Rajshahi campus, Bangladesh. The rate of their presence differed in plant to plant of a family and different families. The highest root colonization (98±1.0%) was found to be present in Xanthium strumarium (Asteraceae). Mycorrhiza was not found in the root of Sphagneticola calendulacea (Asteraceae), Cestrun nocturnum (Solanaceae), Acacia nilotica and Acacia catechu (Mimosoidae), Rorippa nasturtium, Brassica oleracla var botrytis (Brasicaceae), Punica granatum (Lythraceae), Tecoma capensis (Bignoniacea), Spinacia oleracia (Chenopodiaceae), Chenopodium album (Goosefoot). Result of soil analysis reveals that the rhizospheric soils were deficient in nutrients which might be suitable for mycorrhizal symbiosis with plants. In the rhizospheric soils, 22 species of Glomus, Scutelospora, Gigaspora, Archaeospora, and Acullospora were found. We also found the genera ’Glomus’ dominance in the plant root and rhizospheric soil. So, it can be concluded that the highly colonized roots as well as spores can be used to prepare mycorrhizal inoculum for future purposes.

Evaluation of Plant Growth-Promoting and Salinity Ameliorating Potential of Halophilic Bacteria Isolated From Saline Soil

Among the biotic and abiotic stress affecting the physical, chemical, and biological properties of soil, salinity is a major threat that leads to the desertification of cultivable land throughout the world. The existence of diverse and versatile microbial populations inhabiting the nutrient-rich soil and varied soil conditions affects the soil dynamism. A normal soil constitutes 600 million bacteria belonging to about 20,000 species, which is reduced to 1 million with 5,000-8,000 species in stress conditions. Plant growth-promoting rhizobacteria (PGPR) are in symbiotic association with the plant system, which helps in combating the abiotic stress and increases the overall productivity and yield. These microorganisms are actively associated with varied cellular communication processes through quorum sensing and secondary metabolites such as the production of Indole-3-acetic acid (IAA), exopolysaccharide (EPS) siderophore, ammonia, ACC deaminase, and solubilization of phosphate. The present study focused on the isolation, identification, and characterization of the microorganisms isolated from the seacoast of Dandi, Navsari. Twelve isolates exhibited PGP traits at a high salt concentration of 15-20%. AD9 isolate identified as Bacillus halotolerans showed a higher ammonia production (88 ± 1.73 μg/mL) and phosphate solubilization (86 ± 3.06 μg/mL) at 15% salt concentration, while AD32^* (Bacillus sp. clone ADCNO) gave 42.67 ±1.20 μg/mL IAA production at 20% salt concentration. AD2 (Streptomyces sp. clone ADCNB) and AD26 (Achromobacter sp. clone ADCNI) showed ACC deaminase activity of 0.61 ± 0.12 and 0.60 ± 0.04 nM α-ketobutyrate/mg protein/h, respectively. AD32 (Bacillus sp. clone ADCNL) gave a high siderophore activity of 65.40 ± 1.65%. These isolates produced salinity ameliorating traits, total antioxidant activities, and antioxidant enzymes viz. superoxide dismutase (SOD), Glutathione oxidase (GSH), and catalase (CAT). Inoculation of the multipotent isolate that produced PGP traits and salinity ameliorating metabolites promoted the plant growth and development in rice under salinity stress conditions. These results in 50% more root length, 25.00% more plant dry weight, and 41% more tillers compared to its control.