Phosphate Solubilization Research Articles

Using Dominant Phytoplankton as Assessment of Water Quality: Water Resource Case Studies of University in Chatuchak District

The use of dominant phytoplankton as a water quality indicator was studied. Samples from 6 stations (S1-S6) were collected. From the study, 6 divisions of 34 genera of phytoplankton, i.e. Euglenophyta, Chlorophyta, Bacillariophyta, Chromophyta, and Pyrrhophyta were found, and the significant phytoplankton genera were Euglena, Phacus, and Tetraedron. By analysing water quality assessment in terms of scores by AARL-SPP Score using these three dominant genera, it was found that stations S1–S4 had a moderate level of water quality and stations S5–S6 had a moderate-polluted level of water quality. When the relationship between phytoplankton species and the water quality parameters were analysed by stepwise multiple regression analysis, the results showed that the prominent genus Merismopedia of Cyanophyta (Blue-green algae), correlated with transparency, salinity, chlorophyll a, and soluble phosphate while the genus Oscillatoria correlated with the total suspended solids, Chlorophyll a content, transparency, pH, temperature, and ammonia-nitrogen. The correlation indicates the high rate of phytoplankton growth was due to reduced water quality. According to water quality standards for surface water, the water quality was classified in Category 3.

Physio-biochemical responses of three sunflower (Helianthus annuus L.) lines to phosphate solubilizing bacteria and phosphorous-enriched biochar in saline soils

The usage of microbes and biochar (BC) is fundamental in decreasing the impacts of salinity stress by promoting plant growth and development. The purpose of this study was to determine the impact of phosphate solubilizing bacteria (PSB) and phosphorous (P)-enriched BC on the plant growth and biochemical characteristics for three lines of sunflower (Helianthus annuus L.) in saline soils. The study was designed with salinity at 100 mM NaCl and PSB (Bacillus subtilis) with 109 CFU and BC at 1500 Kg ha-1 in the sunflower lines including RGK38 (salt-sensitive), BGK35 (salt-moderately sensitive), and BGK259 (salt-tolerant) based on completely randomized block design (CRBD) in five replicates. Salinity considerably reduced grain yield, thousand grain weight (TGW), oil content, oil yield, chlorophyll (Chl) content, relative water content (RWC), K, and P, while enhancing malondialdehyde (MDA), electrolyte leakage (EL), Na+, and Cl- in all lines of sunflower with high rate in RGK38. The use of integrated PSB and BC contributed to increases in plant yield. In RGK38 exposed to salinity, PSB+BC raised grain yield (16%), oil yield (27%), RWC (14%), Chl a+b (24%), K (22%), P (127%), but lowered MDA (26%), Na+ (36%), and Cl- (41%). Heat map analysis revealed that RGK38 stood out significantly from the other two sunflower lines with the maximum variability under the treatments. MDA showed the most variability among the lines as an indicator of identifying the susceptibility to salinity, PSB, and BC. This study has encouraging implications for agricultural operations in stress-affected areas by highlighting the potential of combining PSB and BC as environmentally acceptable and sustainable ways to increase plant resilience in salty soils.

Biosolubilization of phosphate by strains of Trichoderma in vitro and in greenhouse in three varieties of Coffea arabica

Coffee soils have a low availability of phosphorus, the use of phosphate-solubilizing Trichoderma strains is a promising sustainable strategy for the management of phosphorus deficiencies. In this study in Mexico, we evaluated 10 strains of Trichoderma from the andosol soil of coffee plantations in Mexico and their capacity for phosphate solubilization in vitro, and their impact on the growth of coffee seedlings of three varieties (Anacafé, Costa Rica and Marsellesa) were evaluated. The tested microorganisms showed high phosphorus solubilization, the phosphorus solubilization ranged between 2.41 and 7.40 mg.mL-1. The maximum phosphate solubilizing activity was observed using two strains of Trichoderma harzianum 75.73 (Th53) and 74.62 mg.mL-1 (Th48) for calcium phosphate (Ca2PO4) and three strains of T. asperellum 22.99 (Th57), 22.90 (Th49) and 21.55 mg.mL-1 (Th40) for aluminum phosphate (AlPO4). In both calcium (Ca2PO4) and aluminum phosphate (AlPO4), a decrease in the pH of the medium was detected, from 4.81 to 3.73 and from 3.38 to 2.75, respectively. In the Anacafé variety, the application of two strains of T. harzianum (Th48 and Th53) favored greater availability of phosphorus in the substrate, while in the Costa Rica and Marsellesa varieties the available phosphorus of the substrate was greater with T. harzianum (Th48). Inoculation with these Trichoderma strains is potentially important for the solubilization of insoluble phosphorus and the development of coffee plants.

Isolation and characterization of phosphate solubilizing bacteria from the rhizosphere of lentil (Lens culinaris M.) collected from Hagere Mariam district, Central Ethiopia.

Phosphorus plays a crucial role in regulating many of the plant's metabolic activities by enhancing physiological functions and stimulating biological activities such as nodulation, nitrogen fixation, and nutrient uptake in the soil rhizosphere environment. Inoculants of phosphorus solubilizing bacteria serve as an eco-friendly alternative technology that positively influences both soil sustainability and plant growth. The majority of North Shewa highland areas are characterized by low available phosphorus, primarily acidic, and exhibit strong phosphorus absorption. The objective of this study was to isolate and identify phosphorus solubilizing bacteria from the rhizosphere of lentils and characterize their phosphate solubilizing activity. The cultural, biochemical, physiological microbial analysis was conducted in the microbiology laboratory, department of biology. Pikovskaya's medium was utilized for the isolation, screening, and maintenance of phosphate solubilizing bacteria. Phosphate Solubilizing Bacteria were isolated using tri-calcium phosphate as the sole source of phosphorus in indicator plates. Fifteen phosphate solubilizing bacteria were isolated from lentil rhizosphere soil samples, among which six were the most efficient phosphate solubilizers designated as PSBYE, PSBYR, PSBYM, PSBYL, PSBW, and PSBSW. All isolates notably solubilized tri-calcium phosphate compared to the uninoculated control. The highest phosphorous solubilization was observed from the isolate PSBYL, with a value of 10.61mg/50ml, followed by PSBW with a value of 9.08 mg/50ml. The decrease in pH value correlated with the levels of tri-phosphate solubilization in the PVK broth by the PSB isolates. The pH dropped to 4.64 from the initial pH of 7.2 when grown in the broth, which suggests that the production of organic acids is likely the primary mechanism for phosphate solubilization.

Scrutinizing harsh habitats endophytic fungi and their prospective effect on water-stressed maize seedlings.

Drought constitutes a significant abiotic stressor that hinders plant growth and productivity in many countries. Habitat-adapted endophytic fungi offer an environmentally sustainable approach to address this issue by promoting plant development and enhancing resilience against abiotic stresses. In this study, 30 endophytic fungal isolates were recovered from some wild plants in the extreme habitats of Port Said Governorate, Egypt, and evaluated for their drought tolerance using polyethylene glycol (PEG-6000). Only eight isolates demonstrated drought tolerance properties and were further evaluated for their plant growth-promoting biochemical activities and ability to improve maize germination under simulated drought conditions. All eight isolates exhibited enzyme activity for endo-1,4-β-glucanase, amylase, and pectinase, and most displayed significant nutrient mobilization, with siderophores production ranging from 4 to 89%, ammonia production from 1 to 7μmol/ml, and phosphate solubilization from 129to 256µg/ml. Additionally, all isolates showed strong antioxidant activity and high total phenolic content, with some also producing notable levels of indole acetic acid (IAA) and gibberellic acid (GA3) as plant growth hormones. Coating maize grains with spore suspensions of the eight fungal isolates, in general, significantly increased their germination parameters and seedling vigor in vitro under 8% PEG-6000. This enhancement was particularly pronounced with Neurospora sitophila (P8L4M1) and Penicillium tardochrysogenum (P15L4M1), which increased the vigor of maize seedlings by approximately 308% compared to untreated control. Molecular identification of P8L4M1 and P15L4M1 was performed by amplifying the 28S rRNA gene. This study disclosed unique endophytic fungal isolates with promising potential for enhancing drought resistance in maize.

Screening of multi-metal tolerant plant growth promoting bacteria (PGPB) Stutzerimonas stutzeri WA4 and its assistance on phytoextraction of heavy metals (Cu, Ag and Pb)

In the current study, coal fly ash contaminated soil was collected in and around Mettur Thermal Power Station, Salem district, Tamil Nadu. The metal concentrations present in the coal fly ash soil samples were analyzed and also used for the isolation of bacteria. The isolates were screened for their multi-metal resistance against three heavy metals (Cu, Ag and Pb) and plant growth-promoting traits (siderophore, phosphate solubilization, IAA, cellulase, HCN, and ammonia production). Among the 12 isolates, the WA4 strain revealed promising results for both metal-resistant and plant growth-promoting activity. In the in vitro pot experiment, Spinacia oleracea (Palak), Red amaranth (Red spinach), Capsicum annum (Green chilly) and Solanum melongena (Brinjal) plants were grown in ash-contaminated soil treated with different concentrations of selected bacterial inoculum (25%, 50%, 75% and 100%) along with a control pot. The results of the study indicated that the ash-contaminated soil treated with bacterial inoculum distinctly increased the growth of plants when compared to untreated soil (control). Thus, the best-performing strain WA4 could be utilized as a good bio-stimulant for promoting the growth of selected plants in the re-vegetation programs of ash-contaminated soil.

From Waste to Worth: Using Fermented Orange Pomace in Sustainable Feed Production.

Modern agriculture faces the dual challenge of producing environmentally friendly feed while minimizing chemical fertilizers and energy use. This study evaluates the use of orange pomace fermentation liquor (OPFL) as a bio-fertilizer to enhance the growth and nutritional content of sprouted barley for sustainable feed production. We conducted multiple assays to determine OPFL's growth-promotion potential, including in vitro phosphate solubilization, indole-3-acetic acid (IAA) production, biofilm formation, and antimicrobial effects. Biosafety assays confirmed the absence of coliforms and hemolytic activity. Four barley varieties (Giza 2000, Giza 138, Giza 132, and Giza 126) were treated with OPFL in a hydroponic germination system, with significant improvements observed across several parameters. For example, in Giza 2000, chlorophyll content increased from 4.28 to 4.74, protein content rose from 12.15% to 22.07%, and plant height grew from 13.6 cm to 16.4 cm, representing increases of 10.7%, 81.6%, and 20.6%, respectively. Fresh biomass yield also saw a slight increase, though not statistically significant. This comprehensive evaluation suggests that OPFL is a sustainable alternative to chemical fertilizers, enhancing barley yield and quality in animal feed systems.

Enhancement of the Plant-Accessible Phosphate Fraction in Sewage Sludge Ashes by Na+ or K+ Addition Prior to Combustion.

With the aim of transforming sewage sludge into a P-fertiliser material in a single combustion step, the chemical processes underlying sewage sludge combustion were analysed using powder X-ray diffraction (P-XRD), infrared spectroscopy (IR), thermogravimetric (TGA) as well as elemental analyses (EA). In addition to the combustion of sewage sludge on its own ("mono-combustion"), additions of different additives prior to the combustion step were also carried out. Based on the very positive effects of the additives sodium and potassium carbonate on the obtained ashes concerning their phosphate solubilities in neutral ammonium citrate (NAC) solution, sewage sludge combustions after additions of Na2CO3 or K2CO3 were investigated in detail. We found that these additions altered the main phosphate-containing product found in the ashes from whitlockite (Ca9(Mg,Fe)(PO3OH)(PO4)6), a hardly plant-accessible species, to other phosphate containing compounds such as buchwaldite (CaNaPO4), which is known for a long time as a very good P‑source for plants. Consecutive greenhouse experiments with maize (Zea mays L.) as test plant confirmed the results of the chemical analyses and demonstrated that Na- or K-ashes obtained from a "co-combustion" of sewage sludge mixed with alkali carbonates exhibit relative P-fertilising efficiencies of up to ~80% in comparison to commercial superphosphate.

Isolation and characterization of non-rhizobial bacteria and arbuscular mycorrhizal fungi from legumes

This study investigates non-rhizobial endophytic bacteria in the root nodules of chickpea (Cicer arietinum L), faba bean (Vicia faba), and cowpea (Vigna unguiculata L. Walp), as well as arbuscular mycorrhizal fungi in the rhizospheric soil of chickpea and faba bean. Out of the 34 endophytic bacterial populations examined, 31 strains were identified as non-rhizobial based on nodulation tests. All strains were assessed for their plant growth-promoting (PGP) activities in vitro. The results revealed that most isolates exhibited multiple PGP activities, such as nitrogen fixation, indole-3-acetic acid (IAA) and ammonia (NH3) production, phosphate solubilization, and exopolysaccharide production. The most effective PGP bacteria were selected for 16S rRNA analysis. Additionally, a total of 36 species of native arbuscular mycorrhizal fungi (AMF) were identified. Acaulospora (100%) and Scutellospora (91.66%) were the most prevalent genera in Cicer arietinum L. and Vicia faba L. plants, respectively. Acaulospora also exhibited the highest spore density and relative abundance in both plants. Moreover, the root colonization of Cicer arietinum L. and Vicia faba L. plants by hyphae, vesicles, and arbuscules (HVA) was significant. The findings of this study provide valuable insights into non-rhizobial endophytic bacteria associated with legume root nodules and the diversity of AMF. These organisms have great potential for PGP and can be manipulated by co-inoculation with rhizobia to enhance their biofertilizer effectiveness. This manipulation is crucial for promoting sustainable agriculture, improving crop growth, and advancing biofertilizer technology.

Pengaruh Campuraan Bakteri Pelarut Fosfat dan Bakteri Penambat Nitrogen terhadap Pertumbuhan Tanaman Jagung pada Lahan Kelapa Sawit (Elaeis guineensis Jacq.) Menghasilkan

Intercropped farming utilizez used open spaces as an alternative to making empty land more productive. In certain periods, oil palm plantations have open spaces that can be used for planting intercropped plants. The problem is, in general, that oil palm plantations are planted on marginal land, such as inceptisol that is weak in phosphate, so if they are planted with palm oil, it is necessary to provide fertilizer with the main macro element content for palms to grow optimally, such as phosphorus (P) and nitrogen (N). Efforts can be made to meet the P and N requirements by applying combinations of microorganisms such as phosphate solubilizing bacteria (PSB) and nitrogen-fixing bacteria (NFB). The study aims to find out the effect of various dosages of PSB and NFB combinations on the growth and yield of corn crops, as well as the effect of corn crops on the growth and physiology of palm oil crops. The experiment was conducted at the Ciparanje Experimental Farm, Faculty of Agriculture, Padjadjaran University, January to April 2024. The study used a randomized block design (RBD) with six treatments repeated four times. The treatments included the application of a combination of Pseudomonas sp. and Azotobacter sp., which included: 10 kg/ha of PSB and NFB per plant, 20 kg/ha of PSB and NFB per plant, 30 kg/ha of PSB and NFB per plant, 40 kg/ha of PSB and NFB per plant, and 50 kg/ha of PSB and NFB per plant. Experimental results showed that the PSB and NFB mixture increased crop height 5.28%, stem diameter 3.19%, cob length 9.2%, cob diameter 9.8%, dried weight by 100 seeds 14.5%, and dried weight by corn plant 33.46%. The 40 kg/ha and 50 kg/ha dose of PSB and NFB per plant is the most efficient dose for the growth and of palm oil crops producing 2.

Management of soil phosphorous using phosphate solubilizing microorganisms: A sustainable approach

Phosphorus is crucial for plant growth and productivity, and its scarcity in soil negatively affects crop yields. A major portion of chemical phosphate fertilizer precipitates with soil minerals, making it unavailable for plant growth. Phosphate-solubilizing microorganisms play a pivotal role in enhancing phosphorus availability, facilitating better nutrient absorption, and ultimately boosting plant growth. This article presents a brief overview of the phosphorus status in Indian soil, discusses the various forms of phosphorus and its dynamics across different soil types, and analyses the factors involved, highlighting the importance of phosphorus management for sustainable agriculture. Physiological and molecular mechanisms of microbial phosphate solubilization provide deep insights into exploring PSMs for managing phosphorous in different soil types. It also provides a path for the necessity to explore the multifarious plant growth-promoting traits of PSMs underscoring its applicability for sustainable agricultural practices with viable economy. The mechanism of solubilization of phosphorus has been discussed to understand the role of microorganisms in different soils. The study highlights the role of significant microorganisms in developing tailored consortia of PSMs and other plant growth-promoting rhizobacteria (PGPR) based on the chemical composition of the soil, along with an integrated nutrient approach incorporating PSMs. This review offers valuable insights into harnessing PSMs and their practical applications, facilitating their broader adoption in agricultural systems to maintain soil health.

Impact of Combining Bio-Inoculants along with Inorganic Fertilizers on Soil Biological Characteristics in Transplanted Rice (Oryza sativa L.) Crop

A field experiment was carried out during the Kharif season in the year 2022 to assess the impact of inorganic fertilizers along with Bio-inoculants on soil biological properties in rice (Oryza sativa L.). The experiment consists of seven treatments viz., T1 Control, T2 100% RDF (150, 60, 40 N2, P2O5, K2O kg ha-1), T3 80% RDF + 10 kg BGA ha-1 Soil application + PSB (Phosphate solubilizing bacteria) 3kg/ha, T4 60% RDF + 10kg BGA ha-1 Soil application + PSB, T5 80% RDF + 500kg Azolla ha-1 Soil application +PSB, T6 60% RDF + 500kg Azolla ha-1 Soil application +PSB and T7 10kg BGA ha-1 Soil application + 500kg Azolla ha-1 Soil application + PSB were comprised in Randomized Block Design with three replication. The incorporation of inorganics, Azolla PSB, and BGA (bio-inoculants) actively activated microbial activities, resulting in a greater increase in the populations of total bacteria, actinomycetes, and fungi was observed throughout all growth stages, regardless of the treatments applied, when compared to their initial densities. This phenomenon supports the notion of a stronger rhizosphere effect. This trend aligns with the rise in organic carbon content. Moreover, soil dehydrogenase, alkaline phosphatase activities, along with microbial biomass carbon, displayed an upward trend in tandem with the progressive growth phases of the rice plant.

Phosphate-solubilizing fungus (PSF) - mediated phosphorous solubilization and validation through Artificial intelligence computation.

Phosphate-solubilizing fungus (PSF) strain alaromyces funiculosus was investigated for phosphorus solubilization, utilizing a range of pH levels and phosphate sources, followed by data confirmation through artificial intelligence modeling. T. funiculosus strain was exposed to five different phosphate sources [Ca3(PO4)2, FePO4, CaHPO4, AlPO4, and phytin] at different pH levels (4.5, 5.5, 6.5, 7.0, and 7.5). ANOVA, Pareto charts, and normal plots were used for analyzing the data. Artificial intelligence-based multilayer perceptron (MLP), random forest (RF) and extreme gradient boosting (XGBoost) models were used for data validation and prediction. Five-fold more phosphate (P) solubility by T. funiculosus was registered as compared to the control. The maximum soluble P was found at pH 4.5 (318324 ppb) and CaHPO4 (444045 ppb). Combination of phytin × 4.5 pH yielded the highest dissolved phosphorus (1537988 ppb), followed by 127458 ppb from the control × 4.5 pH. Pareto chart and normal plot analysis showedthe negative impact of pH (B), pH × F/C (fungus/control) × P-Source (ABC), and F/C (A) factor. Whereas pH × P-Source (AC) and P-Source (C) has positive impact on P solubility. The maximum R2 scores showed the order of RF (0.944) > MLP (0.938) > XGBoost (0.899). T. funiculosus strain has a grain potential for sustainable use for different types of phosphate sources. Application AI/ML models based on different performance metrics predicted the validated the attained results. In future research, it is recommended to check the efficacy of developed strategy under field conditions and to check the impact on soil and plant.

Implication of phosphate solubilizing microbial formulations on biomass and yield of chickpea (Cicer arietinum)

Implication of phosphate solubilizing microbial formulations on biomass and yield of chickpea (Cicer arietinum)

Outside-in enhancement of phosphate solubilizing bacteria by sludge biochar for phenol remediation in soil: Pollution stress reduction, electron transfer gain and secretion regulation

The high toxicity of phenol poses a significant barrier to bacterial bio-removal capacity. This study innovatively proposes the utilization of sludge biochar (SB) to embed phosphate-solubilizing bacteria (CZB1), creating a composite system (SB-CZB1) that enhances the bio-removal efficiency of phenol. The research findings indicate that after being embedded with biochar, Phosphorus solubilizing bacteria (PSB) achieved a significant enhancement (49.7 %-67.0 %) in phenol removal efficiency across different concentration gradients (1500, 2000, 2500 mg/L). SB component in the SB-CZB1 composite system provides a stable and favorable growth environment for CZB1, significantly enhancing microbial metabolic activity. Notably, it stimulates CZB1 to secrete succinic acid and malic acid (with increases of 3.8 % and 23.9 %, respectively), effectively mitigating the detrimental effects of phenol toxicity on microorganisms. Three-dimensional fluorescence and electrochemical analysis demonstrate that SB not only exhibits exceptional electrochemical performance but also stimulates CZB1 to generate redox-active substances (quinone components in humic acid). The electron transfer rates between microorganisms and phenol in the SB-CZB1 system are 9.75–21.71 times and 23.94–63.95 times higher than those in SB and CZB1 alone, respectively. Meanwhile, the abundant oxygen-containing functional groups (COH/COC, COOH, CO) on the surface of SB-CZB1 play a pivotal role in the adsorption and removal of phenol. Furthermore, pot experiments further reveal that the SB-CZB1 composite system significantly enhances the removal efficiency of phenol in soil (98.1 %). Additionally, the application of SB-CZB1 effectively modulated soil properties, notably increasing available potassium and available phosphorus content by 40.86 % and 136.69 %. This application not only enriched soil microbial diversity but also promoted the proliferation of native organic pollutant remediation bacteria in the soil. Notably, the proliferation of Bacillus species affiliated with CZB1 was the most significant, increasing by 82.1 %. This result confirms that biochar embedding technology effectively enhanced the colonization of CZB1 in the soil, thereby significantly accelerating the bio-removal process of phenol.

Prospects of iron solubilizing Bacillus species for improving growth and iron in maize (Zea mays L.) under axenic conditions

Iron (Fe) deficiency in calcareous soils is a significant agricultural challenge, affecting crop productivity and nutritional quality. This study aimed to isolate, characterize, and evaluate Fe solubilizing rhizobacterial isolates from maize rhizosphere in calcareous soils as potential biofertilizers. Forty bacterial isolates coded as SG1, SG2, …, SG40 were isolated and screened for siderophore production, with ten showing significant Fe solubilizing capabilities. These isolates were further assessed for phosphate solubilization and exopolysaccharides production. The selected bacterial isolates were also screened under axenic conditions for their ability to improve maize growth. The isolates SG8, SG13, SG24, SG30 and SG33 significantly enhanced growth parameters of maize. Notably, SG30 showed highest increment in shoot length (58%), root length (54%), root fresh and dry biomass (67% and 76%), SPAD value (67%), relative water contents (69%), root surface area (61%), and Fe concentration in shoots (79%) as compared to control. The biochemical characterization of these strains showed that all these strains have capability to solubilize insoluble phosphorus, produce indole-3-acetic acid (IAA), and ammonia with catalase, urease and protease activity. Molecular identification through 16s rRNA gene sequencing confirmed high similarity (99.7–100%) of the selected isolates to various Bacillus species, including B. pyramidoids, B. firmicutes, and B. cereus. The study provides a strong base for developing eco-friendly, cost-effective biofertilizers to address Fe deficiency in crops and promote sustainable agriculture.

Microbe-Friendly Plants Enable Beneficial Interactions with Soil Rhizosphere Bacteria by Lowering Their Defense Responses.

The use of plant growth-promoting rhizobacteria presents a promising addition to conventional mineral fertilizer use and an alternative strategy for sustainable agricultural crop production. However, genotypic variations in the plant host may result in variability of the beneficial effects from these plant-microbe interactions. This study examined growth promotion effects of commercial vegetable crop cultivars of tomato, cucumber and broccoli following application with five rhizosphere bacteria. Biochemical assays revealed that the bacterial strains used possess several nutrient acquisition traits that benefit plants, including nitrogen fixation, phosphate solubilization, biofilm formation, and indole-3-acetic acid (IAA) production. However, different host cultivars displayed genotype-specific responses from the inoculations, resulting in significant (p < 0.05) plant growth promotion in some cultivars but insignificant (p > 0.05) or no growth promotion in others. Gene expression profiling in tomato cultivars revealed that these cultivar-specific phenotypes are reflected in differential expressions of defense and nutrient acquisition genes, suggesting that plants can be categorized into "microbe-friendly" cultivars (with little or no defense responses against beneficial microbes) and "microbe-hostile" cultivars (with strong defense responses). These results validate the notion that "microbe-friendly" (positive interaction with rhizosphere microbes) should be considered an important trait in breeding programs when developing new cultivars which could result in improved crop yields.

Interaction with IP6K1 supports pyrophosphorylation of substrate proteins by the inositol pyrophosphate 5-InsP7.

Inositol pyrophosphates (PP-InsPs) are a sub-family of water soluble inositol phosphates that possess one or more diphosphate groups. PP-InsPs can transfer their β-phosphate group to a phosphorylated Ser residue to generate pyrophosphorylated Ser. This unique post-translational modification occurs on Ser residues that lie in acidic stretches within an intrinsically disordered protein sequence. Serine pyrophosphorylation is dependent on the presence of Mg2+ ions, but does not require an enzyme for catalysis. The mechanisms by which cells regulate PP-InsP-mediated pyrophosphorylation are still unknown. We performed mass spectrometry to identify interactors of IP6K1, an enzyme responsible for the synthesis of the PP-InsP 5-InsP7. Interestingly, IP6K1 interacted with several proteins that are known to undergo 5-InsP7-mediated pyrophosphorylation, including the nucleolar proteins NOLC1, TCOF and UBF1, and AP3B1, the β subunit of the AP3 adaptor protein complex. The IP6K1 interactome also included CK2, a protein kinase that phosphorylates Ser residues prior to pyrophosphorylation. We observe the formation of a protein complex between IP6K1, AP3B1, and the catalytic α-subunit of CK2, and show that disrupting IP6K1 binding to AP3B1 lowers its in vivo pyrophosphorylation. We propose that assembly of a substrate-CK2-IP6K complex would allow for coordinated pre-phosphorylation and pyrophosphorylation of the target serine residue, and provide a mechanism to regulate this enzyme-independent modification.

Influence of Potassium and Phosphate Solubilizing Bacteria on Growth and Development of Davana ( Bees)

Influence of Potassium and Phosphate Solubilizing Bacteria on Growth and Development of Davana ( Bees)

Effects of long-term nitrogen and phosphorus fertilization on soil phosphorus forms and dynamics under continuous wheat production in Saskatchewan, Canada

Many agricultural crops require both nitrogen (N) and phosphorus (P) fertilizers to sustain crop yields. However, long-term application of NH4–N fertilizers can cause soil acidification, which alters soil abiotic and biotic processes, including soil P dynamics. Long-term continuous wheat plots in Saskatchewan, Canada, were used to assess effects of N and P fertilization from 1967 and P fertilizer cessation in subplots from 1995. General soil chemical properties and soil P pools and forms were determined and then correlated with soil pH, total N (TN), and total P (TP) concentrations to show the relative importance on soil P dynamics of (a) crop nutrition (TN and TP); (b) soil acidification (pH); or (c) P fertilization/cessation. Fertilization with NH4–N decreased soil pH and altered exchangeable cation concentrations; however, long-term crop growth was poor in no-N plots and was best with both N and P fertilizers, in turn increasing soil carbon and organic matter. Applying P fertilizers without N increased soluble phosphates and the risk of P losses in runoff. Soil organic P (TPo) concentrations were correlated negatively to pH and positively to TN, but the concentrations of P compounds were not correlated to pH. This suggests that TPo accumulation may be from increased long-term crop residue inputs from crops with N and P fertilizers, rather than increased sorption from reduced pH. However, soil pH will continue to decrease with continued NH4–N fertilization, affecting soil chemistry and future P cycling; monitoring with a suite of wet chemistry and spectroscopic techniques is recommended.