Phosphorus Deficiency Research Articles

From Practice to Science: Assessment Soil Nutrient Status Using “Minus One Element Technique (MOET)” for Early Growth of Maize

Soil nutrient deficiency will influence maize growth, so it is necessary to add nutrients based on the fertility status of the soil. One way to find out the nutrient soil status using a simple method is using the minus one element technique (MOET). The minus one element technique (MOET) determines which element is the limiting factor. This study was carried out to confirm the nutrient soil status using the minus one element technique (MOET) with the early growth of maize as the indicator. The research was conducted in greenhouse, Polytechnic of Lamandau, Central Borneo, Indonesia, at an altitude of 50 m above sea level. The research used a non-factorial design arranged in a completely randomized block design and five fertilizer treatments based on the minus one element technique consisting of control (without fertilization), PK, NP, NK, and NPK with three replications. The results showed that the deficiency of nitrogen, potassium, and phosphorus reduced the growth of maize, leaf greenness, photosynthetic rate, and especially the total dry weight of the plant. The dry weight of maize roots decreased by 18.85% - 75.47% when N, P, and K fertilizer were not applied. Then the decrease in photosynthesis rate ranged from 18.23% to 46.21% when N, P, and K fertilizer were not applied. The low of photosynthesis rates resulted in the accumulation of plant dry weight was hampered, and there was a decrease of 8.00% -74.43%. The results of the evaluation of fertility status are based on the results of the relative dry weight of the plant, which was

Prymnesium parvum: Correlation between lytic activity and prymnesins content, both increasing with phosphorus-depletion and lower cell density

The haptophyte Prymnesium parvum is a widespread microalgae associated with fish kill events. It is a mixotrophic alga, which combines different trophic modes of nutrient and energy acquisition, in part relying on the consumption of prey, a process in which its toxins, the prymnesins (PRMs) are suspected to be involved. Investigating toxicity, and more specifically quantifying PRMs, is challenging because of a lack of standards. In this study, two experiments were conducted to better understand the effects of phosphorus sufficiency and deficiency, growth phase and cell density on lytic activity and PRMs content (intra- and extracellular) of one strain of P. parvum (CCAP 946/6). In the first experiment, P. parvum cultures were grown with or without addition of phosphorus as either inorganic nutrient and/or an algal prey (i.e. the cryptophyte Teleaulax amphioxeia). In the second experiment, a phosphorus-starved culture of P. parvum was inoculated at three initial cell densities in phosphorus-deficient medium. Detection and quantification of phagotrophic activity and toxin content were performed using flow cytometry and liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS), respectively. In addition, to assess the lytic activity of P. parvum, microalgal bioassays were performed on the supernatant towards a competitor, T. amphioxeia. Our results show for the first time a positive correlation between PRMs content and lytic effect on T. amphioxeia. Interestingly, predation had no effect on the PRMs, neither intra- nor extracellular forms, and the toxin content was mainly influenced by the depletion of inorganic phosphorus. Secondly and unexpectedly, lytic effect and PRMs content were higher at lower cell densities in phosphorus-deficient medium. These data provide new insights into the factors promoting the toxicity of P. parvum which may support the development of standards that could help to understand the role and mode of action of these toxins, and their impact on ecosystems.

An Approach to Develop a Model to Detect the Phosphorus and Potassium Deficiency in Paddy Crop on Agriculture Farm Using DIP ML

Excessive use of fertilizers harms the environment and disrupts plant habitats, while also raising costs for farmers. Proper timing and amounts of nutrients are crucial for plant health and environmental balance. The greenness of rice leaves indicates their chlorophyll and nutrient levels. Agronomy studies show rice plants need 10 nutrients, including primary ones like Nitrogen (N), Phosphorus (P), and Potassium (K), and secondary ones like Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn), Boron (B), Molybdenum (Mo), and Chlorine (Cl). Leaf nitrogen concentration (LNC) is highly correlated with chlorophyll content. There are several tools on LEAF+ to measure it, such as leaf color (LCC), SPAD, chlorophyll or nitrogen. Since these tools are cost-effective and not available to all farmers, LCC offers farmers the ability to estimate plant nitrogen needs in real-time for efficient fertilizer use and increased rice yield. Notable innovation in agriculture is the Leaf Color Chart (LCC), developed by Japanese experts. It measures chlorophyll levels in rice plants and aids in nitrogen management without harming the plant. Today, LCC is used globally to improve production efficiency and optimize nitrogen application rates. The remaining 2 major nutrients potassium and phosphorus can also be measured by experimentally expanding the available database of LCC, as has been done in the two models developed in this research paper.

Bacillus amyloliquefaciens promotes cluster root formation of white lupin under low phosphorus by mediating auxin levels

Abstract White lupin (Lupinus albus L.) produces cluster roots to acquire more phosphorus under phosphorus deficiency. Bacillus amyloliquefaciens SQR9 contributes to plant growth, but whether and how it promotes cluster root formation in white lupin remain unclear. Here, we investigated the roles of SQR9 in cluster root formation under low-phosphorus conditions using a microbial mutant and virus-induced gene silencing (VIGS) in white lupin. SQR9 substantially enhanced cluster root formation under low-phosphorus conditions. The ysnE gene encodes an auxin biosynthesis enzyme in SQR9 and was associated with cluster root formation, as ysnE-defective SQR9 did not trigger cluster root formation. SQR9 inoculation induced the expression of PIN-formed2 (LaPIN2, encoding an auxin transporter) and YUCCA4 (LaYUC4, encoding an auxin biosynthesis enzyme) in white lupin roots. VIGS-mediated knockdown of LaPIN2 and LaYUC4 prevented wild-type SQR9-induced cluster root formation in white lupin. Finally, white lupin LaYUC4-derived auxin and SQR9-derived auxin pools were both transported by LaPIN2, promoting cluster root formation under low phosphorus conditions. Taken together, we propose that B. amyloliquefaciens promotes cluster root formation in white lupin under low-phosphorus conditions by stimulating auxin biosynthesis and transport. Our results provide insights into the interplay between bacteria and root auxin in crop phosphorus use efficiency.

Identification and expression analysis of phosphate transporter (PHT) genesin Brachypodium distachyon in response to phosphorus deficiency.

Phosphorus (P) is a macronutrient that plays a crucial role in critical plant functions. Phosphate transporters (PHTs) ensure the acquisition and translocation of Pi in the plant, thereby playing a key role in maintaining normal plant growth under Pi deficiency conditions. In Brachypodium distachyon, the grass model system, the function of individual PHT genes, remains largely unknown. Here, we identified the complete PHT gene family in B. distachyon, for the first time, and analyzed their expression profiles under Pi deficiency. Overall, 25 PHT genes in B. distachyon (BdPHTs) were identified, which were divided into four clades (PHT1-4). BdPHT genes were found to be unevenly distributed across the five chromosomes. Both segmental and tandem duplication events contributed to PHT gene expansion in B. distachyon which underwent a strong purifying selection. Moreover, exon-intron organization and motif composition were conserved within each PHT group consolidating the classification of the phylogenetic tree. Motif composition differs among the four PHT groups, indicating their functional divergence. Gene expression analysis using real-time quantitative PCR revealed that two BdPHT1 genes (BdPHT1.9 and BdPHT1.10) were upregulated in leaves, and seven (BdPHT1.9, BdPHT1.8, BdPHT1.7, BdPHT1.11, BdPHT1.12, BdPHT1.5, and BdPHT1.13) in roots under P deficiency suggesting their involvement in P uptake and translocation. Therefore, these results lay the foundation for future functional analyses in B. distachyon to improve P deficiency tolerance in B. distachyon and other cereals.

Root metabolites regulated by FERONIA promote phosphorus-solubilizing rhizobacteria enrichment induced by Arabidopsis thaliana coping with phosphorus deficiency.

The recruitment of the phosphorus-solubilizing rhizobacteria plays an important role in response to phosphorus deficiency. Through the treatments of Arabidopsis thaliana (Col-0) and the FERONIA (FER) functional deficient mutants (fer-4 and fer-5) with the soil suspension in various phosphorus conditions, we discovered that FER could promote phosphorus-solubilizing rhizobacteria enrichment to rescue the defective plant during phosphorus deficiency. The amplicon sequencing data reflected that the phosphorus-solubilizing rhizobacterial genus Alcaligenes was significantly enriched of Col-0 than fer-4 in low phosphorus conditions. Metabolomics analysis revealed that there were more α-D-Glucose (α-D-Glc) and L-Leucine (L-Leu) in Col-0 roots than those in fer-4 roots. The alterations of α-D-Glc and L-Leu mediated by FER had high-positive correlations to the enrichment of Alcaligenes. We successfully isolated a phosphorus-solubilizing rhizobacteria strain identified as Alcaligenes faecalis PSB15. The α-D-Glc and L-Leu could promote the strain PSB15 growth on LB agar plates and assist fer-4 in recovering from phosphorus starvation in the low phosphorus (LP) liquid medium vermiculite with tricalcium phosphate (TCP). The α-D-Glc and L-Leu could be considered as promising compounds to enrich beneficial phosphorus-solubilizing rhizobacteria, such as Alcaligenes, and provide a reference for overcoming the plight of phosphorus deficiency in crops in the field of agricultural production in the future.

Structural and functional parameters of the Black Sea phytoplankton during the summer bloom of the coccolithophore Emiliania huxleyi

The aim of the study was to examine the main primary production indicators, describe the controlling factors and identify the conditions for the weak bloom of Emiliania huxleyi in the Crimea coast of the Black Sea during June – July 2022. The surface chlorophyll a (Chl a) varied between 0.3 to 1.5mgm-3 and primary production (PP) within 12–174mgC m-3 day-1. The integrated concentration of Chl a in the euphotic layer was 4–29mgm-2, and that of PP - 240–835mgC m-3 day-1. On average, 49% of Chl a was located bellow the photosynthetic zone. The relationship between integral PP and the total Chl a, nitrogen (nitrates and ammonium), phosphates and silicates in the euphotic layer, analyzed by a multiple regression, showed that 70% of the PP variability was accounted for by the first three variables. While the significance of total Chl a was the highest, followed by phosphates, nitrogen had a negligible effect and that of silicates was not detected. In the surface layer (0–1m), the total phytoplankton biomass was co-dominated by dinoflagellates, the large cell diatom Pseudosolenia calcar-avis and the coccolithophore E. huxleyi. A weak bloom of E. huxleyi (cell abundance 1.0–1.8·106 cells L-1) was detected at 11 out of the 23 sampling stations. The relatively large thickness of the upper mixed layer (about 10m on average) and phosphorus deficiency were the main factors limiting the bloom of this coccolithophore.

Effects of Culture Systems and Nutrients on the Growth and Toxin Production of Karenia selliformis.

Harmful algal blooms (HABs) formed by toxic microalgae have seriously threatened marine ecosystems and food safety and security in recent years. Among them, Karenia selliformis has attracted the attention of scientists and society due to its acute and rapid neurotoxicity in mice. Herein, the growth and gymnodimine A (GYM-A) production of K. selliformis were investigated in diverse culture systems with different surface-to-volume (S/V) ratios and nitrogen/phosphorus concentrations. The results showed that the specific growth rates (μ), maximal cell yields, and GYM-A production levels of K. selliformis increased with higher S/V, but no significant differences were observed under different culture volumes with the same S/V, which indicated that light penetration and gas exchange in the seawater culture systems actually influenced the growth and GYM-A production of K. selliformis. The maximum cell density and photosynthetic efficiency of K. selliformis decreased under nitrogen (N) and phosphorus (P) deficiency, suggesting that the growth of K. selliformis was significantly inhibited by the deficiency in N or P. Both N and P limitation conditions, especially P deficiency, promoted the cellular GYM-A quotas of K. selliformis. In this study, a scientific basis is provided for understanding the effects of culture systems and nutrient concentrations on the growth and toxin production of K. selliformis.

Evaluating the Impact of Phosphorus and Solid Oxygen Fertilization on Snap Bean (Phaseolus vulgaris L.): A Two-Year Field Study.

The snap bean (Phaseolus vulgaris L.) is highly sensitive to both phosphorus (P) deficiency and hypoxic stress, which together can significantly hinder plant growth, nutrient uptake, and yield; however, limited information exists on the effect of P and oxygen (O2) fertilization to alleviate these stresses and enhance yield. A two-year field experiment assessed the effects of P and O2 fertilization on plant growth, pod yield, and P uptake in acidic sandy soil. Using a randomized complete block design with four replications, we tested five P rates (0, 45, 90, 135, and 179 kg ha-1 of phosphorus pentoxide, P2O5) in the form of triple superphosphate (TSP) along with two rates (0 and 45 kg ha-1) of solid O2 fertilizer as calcium peroxide (CaO2). Phosphorus and O2 fertilizers improved plant growth and pod yield, with the highest yield from the combination of 135 kg ha-1 P2O5 and 45 kg ha-1 CaO2. Pearson correlation analysis indicated strong associations between plant growth, pod yield, and nutrient accumulation. Principal component analysis (PCA) highlighted notable seasonal differences in snap bean and soil characteristics. This study provides essential insights into the use of O2 fertilizers as a cost-effective approach to mitigate hypoxia, enhance P use efficiency, and improve yield in snap bean. Our findings may inspire the development of sustainable nutrient protocols for high-quality snap bean production and serve as a foundation for similar applications in other crops.

Physiological and Transcriptional Responses to Phosphorus Deficiency and Glucose-6-Phosphate Supplementation in Neopyropia yezoensis.

Neopyropia yezoensis, a marine red algae species, has significant economic and ecological value. However, phosphorus (P) deficiency has emerged as a growing concern in many cultivation regions, negatively impacting its growth. To adapt to P deficiency, algae have evolved various strategies, including using dissolved organic phosphorus (DOP) sources to sustain growth. Despite its prevalence as a form of DOP, the utilization mechanism of glucose-6-phosphate (G6P) by N. yezoensis remains unclear. In this study, the physiological and transcriptional responses of N. yezoensis to P deficiency and G6P supplementation were examined. The results demonstrated that prolonged P deficiency significantly inhibited the growth of N. yezoensis and had a negative impact on physiological indicators such as photosynthetic pigments and antioxidant enzyme activity. However, G6P treatment gradually alleviated these adverse effects over time. Both P deficiency and G6P treatment were associated with increased expression of genes involved in signal transduction and P starvation responses while concurrently downregulating genes related to photosynthesis and antioxidant defenses. In contrast, the suppression of gene expression was less significant under G6P treatment. This study elucidates the adaptive strategies of N. yezoensis in response to P deficiency and clarifies the regulatory pathways involved in G6P utilization, providing novel insights into its P nutrient acquisition and metabolic regulation.

Large physiological plasticity of water- and nutrient-use traits in Quercus ilex L. within and across populations: Implications for Mediterranean forest persistence under global change

Functional traits are essential for predicting plant responses to environmental changes, yet understanding within-species trait variability is complex due to multiple influencing factors. Long-lived trees, like the holm oak (Quercus ilex L.), are expected to respond to abiotic variations largely through phenotypic plasticity, so a better understanding of these plastic responses is key to managing climate change impacts on forests. To investigate intra-specific variations in ecophysiological performance under dry Mediterranean conditions, we measured isotopic, nutrient, and growth traits in 240 four-year-old holm oaks from various populations and mother trees grown in a common garden experiment. Contrary to expectations, we found little ecotypic differentiation in isotopic, nutrient, or growth traits among geographically distant populations with contrasting climates, elevations, and lithologies. Leaf Δ¹⁸Oenrichment and δ13C values ranged widely across and within populations, indicating large variability in time-integrated stomatal conductance and water-use efficiency among neighboring oaks grown under the same dry conditions. Both Δ¹⁸Oenrichment and δ13C exhibited negative relationships with leaf C/P and C/K ratios, revealing a trade-off between water-use efficiency and nutrient-use efficiency that was primarily driven by changes in stomatal regulation stringency depending on leaf nutrient status. Holm oaks from all populations were capable of fine-tuning their leaf gas exchange to prioritize efficient use of the most limiting resource for photosynthesis and growth (water versus nutrients). Phosphorus deficiency and stoichiometric N/P imbalance led to lower water-use efficiency and poorer growth. We conclude that all studied holm oak populations possess sufficient phenotypic plasticity and/or genetic diversity to withstand heat and drought stress intensification through adaptive adjustments of their physiological and nutrient traits. Nonetheless, phosphorus fertilization could greatly enhance forest restoration success amid increasing climatic aridity and human-driven N/P imbalance. These findings hold important implications for a better understanding of holm oaks persistence under rapid climate warming and aridification across the Mediterranean region.

Effect of GR24 on the growth and development of licorice under low phosphorus stress.

Glycyrrhiza, a perennial herbaceous medicinal plant, is extensively utilized in the pharmaceutical industry. The growth of Glycyrrhiza is frequently constrained by soil phosphorus availability, as a significant portion of arable land in China suffers from phosphorus deficiency. This study utilized Ural Glycyrrhiza uralensis Fisch as the subject and examined the application of GR24, a synthetic strigolactone, under three phosphorus conditions: none (P1), low (P2), and high (P3). The research aimed to ascertain the optimal concentration of GR24 for promoting licorice growth and development, thereby providing a theoretical foundation for its agricultural management. The optimal GR24 concentration for P3 and P2 conditions was identified as G3 (10 µM), which enhanced growth metrics, chlorophyll a and b levels, while also boosting antioxidant enzyme activities in licorice. Specifically under P3, significant increases in liquiritigenin and glycyrrhizic acid levels were observed. Under P2, increases were noted in isoliquiritigenin, liquiritigenin, and liquiritin levels. Transcriptome analysis revealed differential gene, with 137 and 270 genes up-regulated and 77 and 294 genes down-regulated in the P3 and P2 treatments, respectively. GO functional enrichment identified 132 and 436 differentially expressed genes for P3 and P2 respectively, while KEGG pathways were predominantly enriched in plant-pathogen interactions and phenylpropanoid biosynthesis. Application of GR24 in P1 conditions did not significantly affect growth indices but did enhance glycyrrhetic acid, isoliquiritin, and liquiritin accumulation. Transcriptome profiling in this treatment identified 465 up-regulated and 1,109 down-regulated genes. GO annotation involved 1,108 differentially expressed genes, and KEGG analysis was primarily enriched in the plant-pathogen interaction pathway. Furthermore, transcription factor analysis revealed alterations in the C2H2, NAC, and MYB families, which are associated with phosphorus response.

Genome-wide association study identified BnaPAP17 genes involved in exogenous ATP utilization and regulating phosphorous content in Brassica napus.

BnaPAP17s associated with root-secreted APases activity were identified by genome-wide association study, and those were induced by Pi-deficiency. BnaPAP17s were involved in improving exogenous organophosphorus utilization as secreted APases. Deficiency of available phosphorus (P) in soil has become an important limiting factor for yield and quality in oilseed rape (Brassica napus). In many soils, organic P (Po) is the main component of the soil P pool. Po must be hydrolyzed to inorganic P (Pi) through acid Phosphatase (APases), and then taken up by plants. However, root-secreted APases (SAP) activity, as a quantitative trait, plays an important role in soil Po utilization; those genetic loci are not clear in B. napus. In this study, we performed a genome-wide association study for SAP activity under Pi-deficiency using a panel of 350 accessions of B. napus and more than 4.5 million polymorphic single nucleotide polymorphisms (SNPs). Thirty-five significant SNPs associated with SAP activity were identified. BnaA01.PAP17 (BnaA01g27810D) was a candidate gene underlying lead SNP (ChrA01_19576615). We experimentally verified that both BnaA01.PAP17 and its three homologous genes had similar expression pattern in response to Pi-deficiency. The dynamic changes in BnaPAP17s expression level were opposite to those of Pi concentration in both roots and leaves, suggesting their potential utility as Pi marker genes in B. napus. Transient expression of BnaPAP17s in tobacco leaves proved that BnaPAP17s were located in the apoplast as secreted APases. The overexpression of BnaPAP17s enhanced SAP activity in response to Pi-deficiency and resulting in increased P content in plants when ATP was supplied as the sole P resource. Taken together, these results suggest that BnaPAP17s contributed to SAP activity, thus having a function in extracellular Po utilization in B. napus.

Genome-wide identification and expression analysis of phosphate-sensing SPX proteins in oats.

Phosphorus is indispensable to plant growth and development. Soil phosphorus deficiency poses a substantial constraint on crop yield. SPXs play pivotal roles in phosphate transport and absorption in plants. Yet, the functions of SPXs of oat (Avena sativa L.) under abiotic stresses remain unclear. In this study, we conducted a genome-wide analysis of 169 SPXs from hexaploid oat and five closely related plant species. All homologous AsSPXs were found to arise from duplication events and depict a strong purifying selection. Subcellular localization prediction revealed that AsSPXs were mainly located on the plasma membrane. Seventeen cis-acting elements, predominantly comprising light-, low temperature-, abscisic acid-, and drought-responsive elements, were dispersed in the promoter regions of AsSPXs. Analysis of cis-regulatory elements, protein-protein interaction networks, and qRT-PCR showed that AsSPXs are not solely involved in phosphorus starvation response but also in various stress responses. Notably, AsSPX18-5D (AVESA.00001b.r3.5Dg0002895) exerted pivotal roles in conferring resistance against low phosphorus, salt, and ABA treatments. Our study aimed to explore important stress-resistant genes in oat. Our results could provide a basis for future studies on the evolution and functions of the AsSPX gene family and a crucial foundation for comprehending how oat responds to environmental stresses.

Root morphology, nitrogen metabolism and amino acid metabolism in soybean under low phosphorus stress.

Phosphorus deficiency is a major influence on growth and development of soybean. Therefore, improving phosphorus utilization efficiency in soybean is a research priority for the soybean community. In this experiment, Liaodou 13 (high phosphorus utilization: HPE) and Tiefeng 3 (low phosphorus utilization: LPE) were used as test varieties. We investigated changes in root morphology, amino acid content, and content of key substances of the nitrogen metabolic pathway with normal phosphorus (0.5 mM) and low phosphorus (0.005 mM) treatments. The results showed that the root length, root surface area and number of lateral roots of HPE roots were higher than those of LPE roots under normal and low phosphorus conditions. The contents of different types of amino acids showed different trends in two varieties. The HPE showed small change in the content of total hydrolyzed amino acids under the low phosphorus condition when compared to the normal phosphorus treatment by a 6.67% decrease, on the contrary LPE showed a drastic decrease by 20.36%. However, HPE exhibited similar decreasing trends in the contents of hydrolyzed and free aspartic acid with the low phosphorus treatment. Moreover, the contents of free histidine and valine in LPE were significantly increased by 657.84% and 149.29% respectively, in contrast to significant decreases in HPE. In aspects of major nutrient elements, the contents of phosphorus, total nitrogen and ammonia nitrogen in both HPE and LPE varieties decreased to dramatic levels. However, the nitrate nitrogen content significantly increased 78.51% for HPE and 65.12% for LPE. Compare to the normal condition, the GOGAT activity in HPE decreased by 5.18% but increased by 33.10% in LPE. Compare to the normal condition, the GS activity in HPE increased by 7.26% but decreased by 21.72% in LPE under phosphorus deficiency. In summary, the phosphorus-efficient soybean variety HPE exhibited superior tolerance to low phosphorus deficiency through advantageous root morphology, phosphorus uptake and transfer capability, and balanced amino acid metabolism and nitrogen metabolism pathways.

Exogenous GABA-Ca Alleviates Growth Inhibition Induced by a Low-P Environment in Peanuts (Arachis hypogaea).

Phosphorus (P) deficiency is a major global factor constraining peanut production. Exogenous γ-aminobutyric acid (GABA) and Ca2+ are essential to improve stress resilience in peanuts growing under low-P conditions. This study therefore examined the detailed physiological effects of GABA-Ca on restoring peanut growth under low-P conditions. These included the root-shoot ratio, leaf nutrients, photochemical activity, reactive oxygen species (ROS), cyclic electron flow (CEF), ATP synthase activity, and the proton gradient (∆pH), all of which were measured under low-P (LP, 0.5 mM) and optimized-P (1 mM) conditions. Specifically, supplying GABA-Ca under LP conditions regulated the ∆pH by causing adjustments in CEF and ATP synthase activities, buffering the photosystems' activities, restoring the antioxidant enzyme system, and lowering ROS production. Interestingly, exogenous GABA-Ca restored peanut growth under low-P conditions, possibly by the putative signaling crosstalk between GABA and Ca2+. The plausible signal amplification between GABA and Ca2+ suggested that the combination of GABA and Ca, may offer an effective strategy for enhancing peanut adaptation to low-P conditions. Moving forward, the strategic supplementation of GABA-Ca, either during cultivation or through the formulation of novel fertilizers, opens up many possibilities for better and more resilient plant production in soils with low P.

High-throughput root phenotyping and association analysis identified potential genomic regions for phosphorus use efficiency in wheat (Triticum aestivum L.).

Association analysis identified 77 marker-trait associations (MTAs) for PUE traits, of which 10 were high-confidence MTAs. Candidate-gene mining and in-silico expression analysis identified 13 putative candidate genes for PUE traits. Bread wheat (Triticum aestivum L.) is a major cereal crop affected by phosphorus (P) deficiency, which affects root characteristics, plant biomass, and other attributes related to P-use efficiency (PUE). Understanding the genetic mechanisms of PUE traits helps in developing bread wheat cultivars that perform well in low-P environments. With this objective, we evaluated a bread wheat panel comprising 304 accessions for 14 PUE traits with high-throughput phenotyping under low-P and optimum-P treatments and observed a significant genetic variation among germplasm lines for studied traits. Genome-wide association study (GWAS) using 14,025 high-quality single-nucleotide polymorphisms identified 77 marker-trait associations (MTAs), of which 10 were chosen as high-confidence MTAs as they had > 10% phenotypic variation with logarithm of odds (LOD) scores of more than five. Candidate-gene (CG) mining from high-confidence MTAs identified 180 unique gene models, of which 78 were differentially expressed (DEGs) with at least twofold change in expression under low-P over optimum-P. Of the 78-DEGs, 13 were thought to be putative CGs as they exhibited functional relevance to PUE traits. These CGs mainly encode for important proteins and their products involved in regulating root system architecture, P uptake, transport, and utilization. Promoter analysis from 1500bp upstream of gene start site for 13 putative CGs revealed the presence of light responsive, salicylic-acid responsive, gibberellic-acid (GA)-responsive, auxin-responsive, and cold responsive cis-regulatory elements. High-confidence MTAs and putative CGs identified in this study can be employed in breeding programs to improve PUE traits in bread wheat.

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.

Effects of Nutrient Deficiency on Crop Yield and Soil Nutrients Under Winter Wheat–Summer Maize Rotation System in the North China Plain

The wheat–maize rotation system in the North China Plain (NCP) has a large amount of crop straw. However, improper crop straw management and blind fertilization lead to nutrient imbalance and accelerated nutrient loss from the soil, ultimately leading to nutrient deficiency affecting the wheat–maize rotation system. In order to explore the effects of nutrient deficiency on the yield and nutrient use efficiency of wheat and maize, the experiment was conducted in a randomized complete block design consisting of five treatments with three replicates for each treatment: (1) a potassium fertilizer deficiency and appropriate nitrogen and phosphate fertilizer treatment (NP); (2) a phosphate fertilizer deficiency and appropriate nitrogen and potassium fertilizer treatment (NK); (3) a nitrogen fertilizer deficiency and appropriate phosphate and potassium fertilizer treatment (PK); (4) an adequate nitrogen, phosphorus, and potassium fertilizer treatment (NPK); and (5) a no-fertilizer treatment (CK). The results showed that, compared with CK, the yields of wheat and maize treated with NPK were increased by 21.5% and 27.5%, respectively, and the accumulation of the dry matter of the wheat and maize was increased by 42.5% and 57.3%. In all the deficiency treatments, the NK treatment performed better in terms of yield compared to the NP and PK treatments, while the NP treatment demonstrated a greater increase in dry matter accumulation. The NPK treatment significantly improved the nitrogen use efficiency (NUE) and nitrogen harvest index (NHI) of the wheat and maize, which resulted in higher nitrogen accumulation in the NPK treatment, and the NP treatment was the best among the other nutrient deficiency treatments. The inorganic nitrogen content showed a similar trend. In conclusion, nutrient deficiency can severely restrict crop growth. Nitrogen deficiency can significantly reduce crop yields. Phosphorus deficiency had a greater impact than potassium deficiency in terms of nutrient absorption and accumulation. Therefore, nitrogen fertilizer application should be emphasized in crop rotation systems, with moderate increases in phosphorus fertilizer application. This practice can effectively improve the nutrient deficiency under the wheat and maize rotation system in the NCP and complete a rational fertilization system.

Pulses as a Key Component in Conservation Agriculture: Impacts on Soil Health and Sustainability

Intensive agriculture poses several challenges such as soil degradation, reduced soil organic matter, and increased soil nutrient imbalances including nitrogen, phosphorus, potassium, sulfur, zinc, iron, and manganese deficiencies and nutrient toxicities (Tiwari KN, 2002). It also contributes to degradation of groundwater quality, declining groundwater levels (Humphreys E et al, 2010), and issues like sodicity and salinization (Tiwari VM et al, 2009), resulting in reduced crop productivity. Many of these limitations can be addressed by adopting conservation agriculture, which supports sustainable productivity while safeguarding natural resources (Sharma AR et al, 2012). Pulses are particularly beneficial in conservation agriculture as they align well with its principles: diversified crop rotations, minimum soil disturbance and continuous soil cover. They serve as a resource-conserving technology that mitigates the adverse impacts of modern agricultural practices.