Search Results (89)

Plant-parasitic nematodes represent a significant threat to agriculture, causing substantial economic losses worldwide. Among the biological alternatives for their control, the genus Trichoderma has emerged as a promising solution for suppressing various nematode species. This article reviews key studies on the interaction between Trichoderma spp. and plant-parasitic nematodes, highlighting the most studied species such as Trichoderma harzianum, Trichoderma longibrachiatum, Trichoderma virens, and Trichoderma viride, mainly against the genera Meloidogyne, Pratylenchus, Globodera, and Heterodera. Trichoderma spp. act through mechanisms such as mycoparasitism, antibiosis, competition for space in the rhizosphere, production of lytic enzymes, and modulation of plant defense responses. They also produce metabolites that affect nematode mobility, reproduction, and survival, such as gliotoxin, viridin and cyclosporine A. In addition, they secrete enzymes such as chitinases, proteases, lipases, and glucanases, which degrade the cuticle of nematodes and their eggs. Furthermore, Trichoderma spp. induce systemic resistance in plants through modulation of phytohormones such as jasmonic acid, ethylene, salicylic acid and auxins. The use of Trichoderma in integrated nematode management enables its application in combination with crop rotation, organic amendments, plant extracts, and resistant varieties, thereby reducing the reliance on synthetic nematicides and promoting more sustainable and climate-resilient agriculture. Full article

Saccharina japonica (S. japonica) is a large-scale intertidal aquatic plant that exhibits characteristics such as rhizoid, holdfast, and blade differentiation. It demonstrates remarkable environmental adaptability. However, compared with higher plants, details about its phytohormone content, distribution, synthesis, and accumulation remain poorly understood. In this study, the phytohormone contents distribution and expression patterns of synthetic genes in different parts of S. japonica, including the rhizoid, petiole, basis, middle, and tip, were analyzed in detail by combining targeted metabolomics and transcriptomics analyses. A total of 20 phytohormones were detected in S. japonica, including auxin, abscisic acid (ABA), cytokinin (CTK), ethylene (ETH), gibberellin (GA), jasmonate acid (JA), and salicylic acid (SA), with significant site-differentiated accumulation. ABA and JA were significantly enriched in the tips (28.01 ng·g⁻¹ FW and 170.67 ng·g⁻¹ FW, respectively), whereas SA accumulated specifically only in the rhizoid. We also identified 12 phytohormones, such as gibberellin A1, methyl jasmonate, and trans-zeatin for the first time in S. japonica. Transcriptomic profiling revealed the tissue-specific expression of phytohormone biosynthesis genes, such as CYP735A (CTK synthesis), in the rhizoids and LOX/NCED (JA/ABA synthesis) in the tips. Key pathways, such as carotenoid biosynthesis and cysteine methionine metabolism, were found to be differentially enriched across tissues, aligning with hormone accumulation patterns. Additionally, an enrichment analysis of differentially expressed genes between various parts indicated that different parts of S. japonica performed distinct functions even though it does not have organ differentiation. This study is the first to uncover the distribution characteristics of phytohormones and their synthetic differences in different parts of S. japonica and elucidates how S. japonica achieves functional specialization through non-specific phytohormone regulation despite lacking organ differentiation, which provides an important theoretical basis for research on the developmental biology of macroalgae and their mechanisms of response to adversity. Full article

Climate-change-induced drought threatens forest restoration by limiting seedling establishment. To address this, we developed synthetic bacterial communities (SynComs) tailored to support drought tolerance in two Mediterranean tree species, Quercus pubescens and Sorbus domestica. Bacteria were isolated from forest soil exposed to long-term drought, sampling across soil depths and root-associated compartments. We selected strains with key plant-beneficial traits, including exopolysaccharide (EPS) production, hormone synthesis (auxin, ABA), siderophore release, and osmotic tolerance. SynComs were assembled based on functional complementarity and ecological origin. Biofilm assays showed that even weak individual producers could enhance community-level performance. After initial screening on Arabidopsis thaliana, the most and least effective SynComs were tested on Q. pubescens and S. domestica seedlings. Compared to controls, the best-performing SynComs reduced the proportion of drought-symptomatic seedlings by 47% in Q. pubescens and 71% in S. domestica, outperforming single-strain inoculants. Notably, EPS-rich SynCom B aligned with the conservative root traits of Q. pubescens, while hormone-rich SynCom F matched the acquisitive strategy of S. domestica. Predictive modeling identified bacterial identity and symptom timing as key predictors of drought resilience. Our results highlight the value of matching microbial traits with plant strategies and drought context for climate-smart forest restoration. Full article

The current study monitored the degree of uptake, distribution, bioaccumulation, and translocation of synthetic auxins (Picloram and Clopyralid) in medicinal plants (Basil). The study’s main objectives were the development and optimization of an analytical method for the identification and quantification of auxins, an optimized method of auxins extraction from soil and plant samples, and, based on the analytical results obtained, the evaluation of bioaccumulation and translocation capacity. To evaluate the effects produced by synthetic auxins on the Basil plant, three experiments were carried out in parallel (Basil-Clopyralid, Basil-Picloram, and Basil-Clopyralid-Picloram) for 15 days, where the plant was permanently exposed to a constant concentration of auxins. The study results showed that in the individual tests and the test carried out in the mixture, the highest concentration was recorded for Clopyralid in the Basil leaves, 16 µg/kg d.w., respectively, 22 µg/kg d.w. The antagonist, Picloram, was primarily detected in the plant’s roots, up to 7.2 µg/kg d.w. Therefore, Picloram favors the accumulation of Clopyralid in high percentages in all plant organs. The bioconcentration factors (BCF) and translocation factors (TF) calculation showed values lower than 1, indicating that Basil is an excluder and has no potential for phytoremediation. Full article

Water scarcity can negatively affect crop yield, posing a significant threat to global food security, such as drought. Plant growth-promoting rhizobacteria (PGPR), either as single strains or synthetic communities (SynComs), has shown promise in alleviating drought stress in various plant species. In this study, we examined the effects of water limitation on Salvia officinalis and the potential of a SynCom composed of five phosphate-solubilizing, auxin-producing, and/or nitrogen-fixing Gram-negative bacteria to enhance plant growth and drought tolerance. Plant growth, morphology, physiology, and leaf metabolomic profiles were assessed using a combination of physiological measurements and LC-MS untargeted metabolomics. Mild water stress induced a conservative water-use strategy in S. officinalis, characterized by increased root-to-shoot ratio and altered leaf morphology, without compromising photosynthetic performance. SynCom inoculation under well-watered conditions elicited drought-like responses, including transient reductions in stomatal conductance. Leaf metabolomic analysis revealed that inoculation influenced the abundance of several metabolites, including biogenic amines and dipeptides, under both irrigation regimes. Notably, drought stress and SynCom inoculation increased histamine and α-ketoglutaric acid levels, highlighting potential impacts on food quality. Under reduced irrigation, inoculation further modulated leaf morphology and biomass allocation, promoting thicker leaves and increased root biomass allocation. These results demonstrate the ability of the SynCom to modulate plant physiology and metabolism in response to both optimal and reduced irrigation, potentially enhancing drought resilience without directly improving growth. The study also highlights the complex interactions among microbial inoculation, plant stress responses, and leaf metabolite profiles, emphasizing the importance of considering the effects on the production of bioactive compounds when developing microbial inoculants for edible plants. Full article

6-Aryl-2-picolinic acid herbicides are an important subclass of auxin herbicides, characterized by their good absorption and conductivity, broad weed control spectrum, and excellent herbicidal activity against some resistant weeds. Based on previous studies from our group and the distinct characteristics of physico-chemical properties and biological activities of active skeleton structure containing fluorine atoms, this paper introduces the design and synthesis of 41 novel 4-amino-6-(5-aryl-substituted-1-pyrazolyl)-3-chloro-5-fluoro-2-picolinic acid compounds. The test of inhibiting A. thaliana roots growth showed that most of the S-series compounds exhibited superior inhibitory effects compared to picloram, with six compounds demonstrated even better inhibitory capability than the new herbicidal molecule florpyrauxifen. For example, compound S202, at a concentration of 0.5 µmol/L, exhibited a 78.4% inhibition of A. thaliana root growth, whereas florpyrauxifen showed only a 33.8% inhibition. Root growth inhibition tests on weeds showed that 28 compounds, at a concentration of 250 µM, demonstrated a greater than 80% inhibition of Brassica napus (BN) root growth. Post-emergence herbicidal activity tests showed that most compounds exhibited good inhibitory effects on broadleaf weeds, with 10 compounds achieving a 100% inhibition of the growth of Amaranthus retroflexus L (AL). These results demonstrate that some of the 4-amino-6-(5-aryl-substituted-1-pyrazolyl)-3-chloro-5-fluoro-2-picolinic acid compounds could be used as potential lead structures in the discovery of novel synthetic auxin herbicides. Full article

DOUBLE-STRANDED RNA BINDING (DRB) proteins DRB1, DRB2, and DRB4 are essential for microRNA (miRNA) production in Arabidopsis thaliana (Arabidopsis) with miR160, and its target genes, AUXIN RESPONSE FACTOR10 (ARF10), ARF16, and ARF17, forming an auxin responsive miRNA expression module crucial for root development. Methods: Wild-type Arabidopsis plants (Columbia-0 (Col-0)) and the drb1, drb2, and drb12 mutants were treated with the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D), and the miR160-mediated response of these four Arabidopsis lines was phenotypically and molecularly characterized. Results: In 2,4-D-treated Col-0, drb1 and drb2 plants, altered miR160 abundance and ARF10, ARF16, and ARF17 gene expression were associated with altered root system development. However, miR160-directed molecular responses to treatment with 2,4-D was largely defective in the drb12 double mutant. In addition, via profiling of molecular components of the miR160 expression module in the roots of the drb4, drb14, and drb24 mutants, we uncovered a previously unknown role for DRB4 in regulating miR160 production. Conclusions: The miR160 expression module forms a central component of the molecular and phenotypic response of Arabidopsis plants to exogenous auxin treatment. Furthermore, DRB1, DRB2, and DRB4 are all required in Arabidopsis roots to control miR160 production, and subsequently, to appropriately regulate ARF10, ARF16, and ARF17 target gene expression. Full article

Pruning is a common forest-tending method; its purpose is to promote growth and improve the overall stand quality. Poplar is a fast-growing, broad-leaved tree species with high ecological and economic value. It is a common management method to promote its growth by pruning and adjusting the spatial structure of the stand, but its potential regulatory mechanism remains unclear. In this study, transcriptome and metabolome data of different parts at all pruning intensities were determined and analyzed. The results showed that 7316 differentially expressed genes were identified in this study. In the plant hormone signal transduction pathway, candidate genes were found in eight kinds of plant hormones, among which the main expression was gibberellin, auxin, and brassinosteroid. Some candidate gene structures (beta-glucosidase, endoglucanase, hexokinase, glucan endo-1, 3-beta-D-glucosidase, beta-fructofuranosidase, fructokinase, maltase-glucoamylase, phosphoglucomutase, and sucrose) were specifically associated with starch and sucrose biosynthesis. In the starch and sucrose biosynthesis pathway, D-fructose 6-phosphate, D-glucose 1,6-bisphosphate, and glucose-1-phosphate were the highest in stems and higher in the first round of pruning than in no pruning. The bHLH plays a key role in the starch and sucrose synthetic pathway, and AP2/ERF-ERF is important in the plant hormone signal transduction pathway. These results laid a foundation for understanding the molecular mechanism of starch and sucrose biosynthesis and provided a theoretical basis for promoting tree growth through pruning. Full article

The rhizosphere, a narrow region of soil surrounding plant roots, is an environment rich in microbial diversity that profoundly influences plants’ health, growth, and agricultural productivity. This microbial community, known as the rhizosphere microbiome, consists of a complex array of bacteria, fungi, archaea, and other microorganisms that engage in complex interactions with plant roots. These microorganisms contribute to nutrient cycling, mineral uptake facilitation, and protection against soil-borne pathogens, thereby promoting plant growth and resilience towards biotic and abiotic stresses. Additionally, microbial signaling molecules, including phytohormones such as auxins, cytokinin, gibberellins, ethylene, and abscisic acid, play a pivotal role in regulating these interactions by modulating plants’ responses to environmental stressors. Recent advancements in microbiomics have enabled a deeper understanding of the rhizosphere’s diversity, composition, and functions, paving the way for more sustainable agricultural practices. By harnessing the potential of the rhizosphere microbiome, innovative strategies can be developed to reduce dependency on synthetic agrochemicals, enhance soil fertility, and increase crop yields. This review discusses the diversity and mechanisms of plant–microbe interactions, focusing on the role of microbial signaling molecules, and explores their applications in promoting agricultural sustainability. The insights gained from microbiomics studies can revolutionize farming practices by reducing dependency on chemical inputs, enhancing crop productivity, and nurturing soil health and environmental sustainability. Full article

The global rise in population has led to an increased demand for food production, necessitating the adoption of sustainable agricultural practices. Traditional methods often rely on synthetic chemicals that negatively impact both human health and the environment. This study aimed to screen soil fungal strains for plant-growth-promoting traits, specifically focusing on their ability to solubilize phosphates, produce indole-3-acetic acid (IAA), and synthesize siderophores. Fungal strains were identified using rDNA sequencing of the ITS regions, and their growth-promoting abilities were assessed in vitro. Aspergillus flavus JKJ7, Talaromyces purpureogenus JKJ12, and Trichoderma koningiopsis JKJ18 exhibited varying degrees of phosphate solubilization, with T. purpureogenus JKJ12 solubilizing the highest amount of tricalcium phosphate (TCP), while A. flavus JKJ7 was the most effective in solubilizing phytic acid calcium salt (PCS). In terms of IAA production, A. flavus JKJ7 produced the highest auxin concentration (68.51 mg/L), followed by T. koningiopsis JKJ18 and T. purpureogenus JKJ12. Additionally, A. flavus JKJ7 produced the highest amount of siderophores (83.7%), indicating its potential for improving iron uptake in plants. Principal Component Analysis (PCA) revealed distinct functional capabilities among the strains, particularly in phosphate solubilization and IAA production, suggesting their complementary use in consortium formulations. These results indicate that these fungal strains possess significant plant-growth-promoting traits and could be used as bioinoculants for sustainable agriculture, either as single strains or in combination Full article

Weeds significantly impact paddy yields, and herbicides offer a cost-effective, rapid, and efficient solution compared to manual weeding, ensuring agricultural productivity. Tripyrasulfone, a novel 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor developed by Qingdao Kingagroot Chemicals Co., Ltd., has demonstrated high efficacy when applied post-emergence, causing characteristic foliar bleaching in susceptible weed species, distinct from conventional acetolactate synthase, acetyl-CoA carboxylase, and synthetic auxin herbicides. This study investigates the impact of tripyrasulfone on the activity of key soil enzymes (urease (UE), acid phosphatase (ACP), sucrase (SC), catalase (CAT), and dehydrogenase (DHA)) in paddy soils from Jilin Province and Shandong Province. Different doses of tripyrasulfone (0.1, 1.0, and 2.5 mg kg⁻¹) were applied, and the enzymatic activities were measured. Results indicated that tripyrasulfone initially inhibited UE and ACP activities before activating them. On the 20th day after treatment, UE activity had returned to control levels, whereas ACP activity remained significantly higher, showing long-lasting activation. SC and CAT activities were inhibited but gradually recovered to control levels. Furthermore, DHA activity was activated with a sustained effect, remaining significantly higher than the control group even 20 days after treatment. Overall, the impact of tripyrasulfone on soil enzyme activities diminished over time, suggesting that tripyrasulfone posed minimal long-term ecological risk to soil health. Full article

Dicamba is a post-herbicide, showing some activity in soil, and its dynamics can be influenced by several factors, including the presence of straw. Brazil has more than 50% of its production area in a no-till system; thus, a good amount of the herbicide is intercepted by the straw. This study aimed to evaluate dicamba dynamics in straw and weed control efficacy when sprayed as a PRE herbicide. For this, five different studies were conducted: we utilized different straw amounts (1) and different drought periods (2) for straw sprayed with dicamba and dicamba + glyphosate to evaluate its release from straw, different straw amounts (3), different drought periods (4), and wet and dry straw (5) to evaluate pre-emergence weed control (Bidens pilosa and Ipomoea grandifolia) and dicamba availability in medium-texture soil. Around 80% of dicamba was released from the straw after 100 mm of rainfall. One day after dicamba application, 65–70% of dicamba was released from the straw with 20 mm of rainfall, while for 7 and 14 DAA, 60% was released. Dicamba was efficient in controlling the pre-emergence of both species studied, and the amount of straw did not interfere in weed control; however, dicamba was less available in the soil after rainfall when sprayed in the straw than when sprayed directly in the soil. Up to 80% of dicamba can be released from the straw after 100 mm of rainfall and weed control was efficient for the species studied; however, the carryover effect in sensitive crops might become an issue. Full article

Microalgae offer distinct advantages as a nutritional source for aquaculture and as a means of wastewater bioremediation. Studying the phycosphere bacteria and understanding their complex interactions is essential to optimizing high-quality biomass growth. This study aimed to isolate, characterize, and identify bacteria from the phycosphere of marine microalgae and to determine their potential to enhance growth, metabolism, and bioremediation capabilities of Chaetoceros calcitrans in stress nutrient-poor media simulating aquaculture wastewater enriched with nitrate, nitrite, or phosphorus. Bacterial characterization included tests for auxin and siderophore production, biofilm formation, amylase activity, phosphate solubilization, mobility, and antagonism evaluation. When Alteromonas macleodii, Bacillus cereus, and Marinobacter sp. were selected and then enriched (10⁷ CFU/mL) in co-culture with C. calcitrans, growth levels significantly increased in four of six Synthetic Aquaculture Wastewater (SAW) media. Pigment levels were higher in five of six SAW media, and lipid levels were higher in SAW rich in nitrite (SAWni50) and phosphorus (SAWpho50). In addition, C. calcitrans with or without the bacterial consortium demonstrated excellent phosphorus bioremediation, achieving 67.6% average removal in SAWpho50. Nitrate and nitrite assimilation rates were approximately 10% in SAWna and SAWni50. This study marks the inaugural identification of these bacteria as microalga growth-promoting bacteria (MGPB) for enhancing growth and lipid and pigment production in C. calcitrans, and it also documents a maximum of 69.13% phosphorus removal. Full article

Herbicide-resistant corn poppy (Papaver rhoeas L.) is one of the most important broadleaved weeds and the number of resistant cases is still growing. The aims of this study were to confirm the resistance of P. rhoeas from Tunisia to ALS inhibitors and auxin mimics and investigate the mechanisms of Target-Site Resistance (TSR) and Non-Target Site Resistance (NTSR) involved. Dose–response trials to determine cross-resistance patterns for ALS inhibitors and auxin mimics were conducted in a greenhouse. In this study, multiple resistance to tribenuron-methyl and dicamba but not to 2,4-D was found in P. rhoeas populations. Cross-resistance to imazamox was confirmed as well. Sequence analysis of the ALS gene detected target-site mutations in codon 197 of the ALS gene, namely, Pro197His, Pro197Thr, Pro197Leu, and Pro197Asn. In this study, the metabolism experiments with malathion (a cytochrome P450 inhibitor) showed that malathion reduced resistance to imazamox, indicating that P450 is involved in the resistance. TSR and NTSR mechanisms to ALS inhibitors likely coexist. The findings of this study revealed a significant synergistic interaction between malathion and dicamba in particular populations, suggesting that the resistance to auxin mimics can be conferred by enhanced metabolism. Full article

Incorporation of red clover (Trifolium pratense L.) into grass pastures can reduce the need for nitrogen fertilizer applications and increase the nutritional value of the forage. However, red clover cultivars available for Kentucky producers are highly susceptible to herbicides, such as 2,4-D (2,4-dichlorophenoxy acetic acid), used for pasture broadleaf weed control. To overcome this problem, ‘UK2014’ red clover was selected for increased tolerance to 2,4-D. We employed a transcriptome analysis approach to compare the gene expression response following 2,4-D treatment of ‘UK2014’ to that of ‘Kenland’, a 2,4-D sensitive red clover and one of the parents of ‘UK2014’. The objectives were to first determine if the increased 2,4-D tolerance in ‘UK2014’ is reflected in a change of transcription response and/or a quicker recovery of a transcriptional response following 2,4-D treatment, and second, to identify genes, whether constitutively expressed or induced by 2,4-D, which could be the basis for the increased 2,4-D tolerance. Leaf tissue from the two red clovers grown in the field was collected at 4, 24, and 72 h after 2,4-D (1.12 kg 2,4-amine a.e. ha⁻¹) treatment from both untreated and treated plants. Global gene expression was determined with reads from Illumina Hiseq 2500 mapped against the red clover draft genome, Tpv2.1 (GenBank Accession GCA_900079335.1). Genes that displayed differential expression (DEGs) following 2,4-D treatment were selected for further analysis. The number of DEGs was higher for ‘Kenland’ than for ‘UK2014’, suggesting that a lower transcriptional response corresponds with the higher 2,4-D tolerance in the ‘UK2014’ line. Similarly, gene ontology enrichment analysis revealed that expression of photosynthesis-related genes was less affected by 2,4-D in the ‘UK2014’ line than ‘Kenland’. Although we were not able to identify any specific genes that are the basis for the increased 2,4-D tolerance of ‘UK2014’, we concluded that the increased 2,4-D tolerance of ‘UK2014’ correlates with a decreased transcription response to 2,4-D. Additionally, expression of several cytochrome P450 genes that had different isoforms between ‘UK2014’ and ‘Kenland’ increased significantly in both following 2,4-D treatment, one or more of these P450s could be mediators of 2,4-D metabolism and tolerance in red clover. Full article