Search Results (2,681)

Cannabis sativa L. is a multipurpose crop of increasing agricultural and medical relevance, whose productivity and phytocannabinoid profile are influenced not only by genotype and environmental factors but also by the composition of its microbiota. This review synthesizes current knowledge (2020–2026) on the rhizosphere and endophytic microbiota of hemp, with particular emphasis on plant growth-promoting bacteria (PGPB) and their mechanisms of action. Molecular studies indicate that hemp-associated bacterial communities are dominated by Proteobacteria, Actinobacteriota, Firmicutes and Bacteroidota, with genotype-, tissue- and developmental-stage-dependent variation. PGPB influence plant performance through direct mechanisms, including biological nitrogen fixation, phosphate solubilization, siderophore production and phytohormone synthesis (indole-3-acetic acid (IAA), gibberellins, cytokinins, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase), as well as indirect mechanisms such as antibiosis, enzyme-mediated pathogen inhibition and induction of systemic tolerance to abiotic stress. Experimental studies demonstrate that inoculation with selected strains or consortia can enhance biomass accumulation, improve germination and root architecture, increase resistance to Fusarium oxysporum and modulate cannabinoid and terpene profiles. Importantly, plant responses are cultivar-specific, highlighting the need for genotype-tailored microbial formulations. Full article

As food demand increases, agricultural practices have evolved, prompting increased exploration of sustainable ecological techniques and utilization of plant-associated microorganisms. In this context, plant fitness has been enhanced by plant growth-promoting microorganisms (PGPM), which stimulate growth through direct mechanisms, such as improved nutrient availability and phytohormone production, as well as indirect mechanisms, including protection against phytopathogens and suppression of soil-borne diseases. However, these innate capabilities of PGPM can be further improved through genomic modification or editing. This article reviews advances in the genomic engineering of plant-beneficial microorganisms as tools to enhance their positive effects on crop performance and environmental remediation. The genetic modification strategies analyzed here include random mutagenesis, targeted genome editing (such as CRISPR-Cas), gene over-expression, genome shuffling, RNA interference, metabolic pathway engineering, and synthetic biology approaches. These tools have enabled the optimization of functions, such as nitrogen fixation, phosphate solubilization, secondary metabolite production, biocontrol, stress tolerance, and bioremediation. However, we propose expanding the discussion of their regulation and use in various countries. Additionally, these modifications must be efficient and safe for the beneficial microbiota associated with the target crop, as well as for humans, animals, and the environment, all of which depend on sustainable agricultural practices. Full article

The ubiquitin-26S proteasome system provides a key mechanism for regulating protein turnover in plants and contributes to the control of diverse developmental and stress-related processes. Within this system, Skp1-Cullin1-F-box (SCF) E3 ligases rely on F-box proteins to confer substrate specificity, enabling selective and dynamic regulation of target protein stability. The large size and structural diversity of the F-box protein family in plants suggest extensive functional specialization, although many members remain poorly characterized. Here, we review recent advances in the understanding of F-box protein function, with a focus on their roles in plant development, stress adaptation, and immunity. Specifically, this review integrates findings across development, abiotic stresses, and immunity to highlight shared and diverging regulatory nodes and critically assesses the strength of substrate evidence to distinguish bona fide from putative F-box targets. We highlight how F-box proteins modulate key regulatory pathways, including phytohormone signaling, reproductive development, root architecture, and secondary metabolism, as well as responses to abiotic and biotic stresses. Emerging evidence indicates that F-box-mediated proteolysis acts as an important layer of control linking environmental signals to downstream transcriptional and physiological outputs. A better understanding of F-box protein substrates and regulatory networks is important for dissecting plant adaptive mechanisms and may provide molecular targets for future crop improvement strategies. Full article

Soybean is the dominant source of plant-derived protein, yet improving seed protein content without reducing yield remains a breeding challenge. While the phytohormone auxin is well-established as a crucial regulator of seed development, its precise role in metabolic homeostasis governing protein accumulation remains largely unexplored. Here, we show that disrupting auxin conjugation via CRISPR-Cas9-generated gh3Q (GH3 quadruple) mutants elevates free auxin levels and is associated with increased seed size, hundred-seed weight, and protein content. Time-course transcriptome profiling of seed coats and embryos identified the R6-stage seed coat as a pivotal tissue for protein accumulation, where seven key seed storage protein genes (2S albumin and 11S glycinin family members) were significantly up-regulated. Weighted gene co-expression network analysis (WGCNA) further uncovered auxin polar transport modules and novel hub genes that are co-expressed with potentially link auxin signaling to protein storage pathways. These findings suggest that auxin homeostasis may link phytohormone signaling and metabolism allocation in soybean seed development. Our study provides genetic targets and a regulatory network for developing high-protein soybean varieties. Full article

Polyamines (PAs) play critical roles in plant growth, somatic embryogenesis (SE), etc. Previous studies have demonstrated that exogenous PAs could promote SE in plants. However, the effects of PAs on Ginkgo biloba L. SE are still unknown, especially in the switch from the initial callus (IC) to the embryogenic callus (EC) stage or to the globular embryo (GE) stage. This work identified 34 genes involved in PA metabolism in G. biloba using genome-wide analyses. These genes were clustered into six families and found to be unevenly distributed across 11 of the 12 chromosomes on the plant. These families contain 539 cis-acting elements that mainly respond to phytohormones, abiotic stress, meristem expression, etc. RNAseq analysis revealed that the expression of GbADC2, GbSAMDC2, GbSPMS1, GbCuAO1 and 3, and GbPAO3, 8, 6 and 13 genes in G. biloba were higher in the GE stage than in the IC stage. In addition, 1.0 mg·L⁻¹ spermine (Spm3) could promote the conversion of IC to EC, while 0.01 mg·L⁻¹ putrescine (Put1) could facilitate the transition from IC to EC and then to GE. During the conversion of IC to EC or to GE, higher levels of abscisic acid (ABA), superoxide dismutase (SOD), and peroxidase (POD) and lower levels ofindole-3-acetic acid (IAA), gibberellin (GA3), and zeatin (ZT) were observed; concurrently, the H₂O₂ level was also observed to be high. Gene expressions of GbSPMS2, GbCuAO3, and GbPAO6 and 8 were upregulated, while GbADC2 expression was downregulated in the EC or GE stages under Spm3- or Put1- treatment. These results illustrate that exogenous PAs might alter the levels of the endogenous polyamine pool and lead to H₂O₂ production, which caused a certain oxidative stress. However, SOD and POD balanced H₂O₂ production and maintained homeostasis. The Pas–H₂O₂–ABA module might coordinate the regulation of early in of G. biloba. These relations were discussed in this work. These findings provide a foundation for comprehending the roles of PA gene families in the key nodes of early SE in G. biloba. Full article

Verticillium wilt (VW), caused by the soil-borne fungus Verticillium dahliae, is a major disease that markedly compromises both the yield and fiber quality of cotton. In this study, we explored the function and underlying mechanism of the cotton expansin gene GhEXLB2 in response to VW infection. Expression profiling revealed that members of the GhEXL family exhibit distinct patterns across tissues and under various biotic and abiotic stresses. Notably, GhEXLB2, which encodes an extracellular protein, showed the strongest induction following V. dahliae challenge. Ectopic expression of GhEXLB2 in Arabidopsis thaliana promoted root elongation and root hair formation, and was associated with improved resistance to the pathogen. In contrast, silencing GhEXLB2 in cotton via virus-induced gene silencing (VIGS) led to pronounced vascular browning, increased pathogen recovery, and a lower level of disease resistance. In addition, RNA-seq profiling of GhEXLB2-silenced (VIGS) cotton plants revealed that most differentially expressed genes were enriched in pathways related to phytohormone signaling and plant–pathogen interactions, with salicylic acid (SA) signaling and WRKY transcription factors emerging as central regulatory components. Analysis of the GhEXLB2 promoter further identified multiple cis-acting elements associated with stress and hormone responsiveness. When integrated with protein–protein interaction (PPI) prediction data, these results suggest that GhEXLB2 may be modulated by a network of transcription factors and signaling pathways. Collectively, the evidence supports a positive association between GhEXLB2 and VW resistance. This study provides a framework for understanding expansin functions in cotton defense against VW. Full article

Cabbage (Brassica oleracea var. capitata), a member of the Brassicaceae family, is an important vegetable crop grown worldwide. Self-incompatibility (SI) in cabbage is a key trait that prevents self-fertilization and inbreeding, thereby maintaining genetic diversity within populations. Although several genes related to SI have been reported, its genetic control remains unclear. In this study, we developed an F₂ population from the highly self-compatible (SC) cabbage line 87-534 and the highly self-incompatible (SI) line 01-20, both of which exhibit the S5 haplotype. The segregation analysis of the F₂ population revealed the possible control of SI by a major gene with additional modifying genetic factors. Bulk segregant analysis sequencing (BSA-Seq) and RNA sequencing (RNA-Seq) were performed on SI and SC samples selected from the F₂ population. BSA-Seq revealed a candidate region on chromosome 7 (C07: 7.45 Mb to 8.93 Mb), including 32 differentially expressed genes (DEGs). RNA-Seq identified a total of 2400 DEGs between the two pools, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses suggested that plant hormone biosynthesis and signaling, plant immune response were significantly enriched and may be involved in SI. The combined analysis of BSA-Seq and RNA-Seq identified six candidate genes associated with SI, and their expression was confirmed using quantitative real-time PCR (qRT-PCR). Among them, Bol023956 encodes fructokinase, Bol023986 is involved in plant defense response, Bol024018 is related to pollen development, Bol024012 encodes a transport protein for phytohormones, Bol023943 encodes chorismate mutase 3, and Bol012515 is an important regulatory gene for chloroplast synthesis. These six genes, potentially linked to SI, should be targets for further validation. These findings provide insights into the molecular mechanisms of SI in cabbage and the selection of superior cabbage varieties. Full article

The GRAS transcription factor family plays a pivotal role in plant stress adaptation, yet its systematic characterization and the underlying drought-responsive mechanisms remain poorly elucidated in Populus deltoides. Here, a genome-wide identification and analysis of GRAS genes in P. deltoides was performed, and a total of 92 family members were identified and classified into 12 distinct subfamilies through phylogenetic analysis. Evolutionary analysis revealed a high degree of conservation between the GRAS proteins of P. deltoides and those of Arabidopsis thaliana, Oryza sativa, and Solanum lycopersicum. Genomic duplication events, including 90 segmental and 11 tandem duplications, were identified as the primary drivers of GRAS family expansion. Promoter cis-element analysis uncovered an enrichment of stress-responsive elements (MBS, ABRE) and phytohormone-related motifs (e.g., TATC-box). Transcriptomic profiling further revealed distinct drought-inducible expression patterns of GRAS genes: PdeGRAS49 exhibited rapid upregulation at the early stage of drought exposure (1–3 h), whereas DELLA subfamily members PdeGRAS51 and PdeGRAS59 reached their expression peaks at 6–9 h, and PdeGRAS34 and PdeGRAS77 maintained sustained activation throughout 12–24 h. Moreover, the drought-inducible expression patterns of five DELLA genes were confirmed by qRT-PCR validation. Collectively, this study provides crucial genomic insights into the GRAS family and valuable candidate gene resources, which lay a foundation for molecular breeding of drought-tolerant P. deltoides cultivars via manipulating GRAS-mediated regulatory mechanisms. Full article

Rice depends on its root system to perceive drought, a major environmental constraint that leads to severe yield losses worldwide. To dissect the underlying molecular basis, we conducted a comparative analysis of drought-sensitive (WAB) and drought-tolerant (IR65) rice genotypes that exhibited divergent drought tolerance at the seedling stage. After exposure to 15% PEG6000 (−0.4 MPa) for two days, the shoot and root architectural traits of IR65 were better than those of WAB seedlings. Measurements of physio-biochemical parameters (SOD, CAT, POD, APX, H₂O₂, and proline) suggest that IR65 seedling roots exhibit greater ROS scavenging and osmotic adjustment capacity than WAB, aligning with tolerance to PEG-induced water deficiency. Transcriptomic assessments of roots identified 802 commonly differentially expressed genes (DEGs) during the drought time course (12, 24, and 48 h) in WAB and IR65. They were clustered into eight groups based on their expression profiles and mainly enriched in phytohormone signaling, protein phosphorylation, and transcription factors. Using weighted gene co-expression network analysis (WGCNA), nine significant modules were identified based on n = 382 of the DEGs. A total of 12 DEGs up-regulated in IR65 were distributed in five modules, and five of them were selected for rapid functional validation through in vivo yeast expression. The results showed that transgenic yeasts were tolerant to simulated drought conditions (135 mM PEG3350), indicating that these genes would be potential targets for rice improvement in drought tolerance in the future. Full article

Iris sanguinea features upright, stiff leaves, making it an excellent cut-foliage material, with its tall leaf architecture greatly enhancing ornamental value in landscaping. However, during the leaf expansion phase, plants frequently exhibit loose foliage arrangement, excessive spreading, and compromised mechanical strength, culminating in lodging and a concomitant decline in ornamental quality. Plant height in I. sanguinea is strongly regulated by phytohormones. This study showed that exogenous GA at concentrations of 50 mg·L⁻¹, 100 mg·L⁻¹, and 200 mg·L⁻¹ increased seedling height by 5.7%, 8.8%, and 12.7%, respectively, through foliar spraying on I. sanguinea seedlings grown ex vitro in a greenhouse; conversely, PAC treatment at equivalent concentrations suppressed growth by 19.3%, 21.0%, and 22.2%, respectively. Two pivotal GA signaling components, GAI and GID1a, were isolated from I. sanguinea. Subcellular localization confirmed that both IsGAI and IsGID1a proteins localize to the nucleus. Overexpression vectors pCAMBIA1300-IsGAI-GFP and pCAMBIA1300-IsGID1a-GFP were constructed and expressed in Arabidopsis thaliana. Transgenic lines overexpressing IsGAI showed significantly reduced plant height, hypocotyl elongation, and bolting, whereas IsGID1a overexpression promoted these traits. Exogenous GA application partially reversed the dwarf phenotype induced by IsGAI overexpression and further potentiated the height enhancement observed in IsGID1a-overexpressing lines. This study identifies two key genes controlling plant height and provides a theoretical basis and genetic resources for precisely engineering plant architecture in I. sanguinea. This is especially important for developing dwarf varieties with enhanced ornamental and agronomic traits, offering significant potential in the landscaping and cut flower industries. Full article

Light availability is a primary determinant of plant growth and a key factor influencing the success of alien plant invasions. Although the phytohormone abscisic acid (ABA) is a known master regulator of abiotic stress responses, its specific role in the shade tolerance and competitive advantage of invasive species remains poorly understood. In this study, we conducted a comparative experiment using the highly invasive Wedelia trilobata and its native congener, Wedelia chinensis. We investigated their eco-physiological responses to normal (100%) and low-light (30%) intensities, coupled with the application of exogenous ABA (A1) and the biosynthesis inhibitor sodium tungstate (S1). Our results showed that low light significantly inhibited the growth and photosynthetic capacity of both species, reducing biomass and net photosynthetic rate P_n. However, exogenous ABA application specifically enhanced the P_n and biomass of the invasive W. trilobata under low-light stress, while reducing malondialdehyde (MDA) content and optimizing antioxidant enzyme activities (SOD, POD, and CAT). Conversely, the inhibition of endogenous ABA by sodium tungstate exacerbated oxidative damage and photosynthetic decline in both species, with a more pronounced negative impact on W. trilobata. Correlation analysis further revealed that W. trilobata maintains a superior capacity to coordinate stomatal regulation and antioxidant defense through ABA signaling. These findings suggest that the invasive success of W. trilobata in fluctuating light environments is significantly driven by its high sensitivity and efficiency in ABA-mediated physiological plasticity, providing a potential target for managing its spread through hormonal or metabolic interference. Full article

Poor seed germination severely limits the propagation and conservation of Zelkova schneideriana (Chinese zelkova). However, the comparative effects of different exogenous phytohormones on seed germination of this species and the associated molecular responses remain insufficiently understood. To evaluate the effects of exogenous phytohormones on seed germination and to explore the underlying molecular basis, a germination experiment was conducted from January to March 2024 at Central South University of Forestry and Technology, Changsha, Hunan, China, in which seeds were treated with different concentrations of 6-benzylaminopurine (6-BA; 20, 40, and 80 mg/L), gibberellic acid (GA₃; 125, 250, and 500 mg/L), indole-3-acetic acid (IAA; 100, 200, and 300 mg/L), brassinolide (BR; 10, 20, and 30 mg/L), and abscisic acid (ABA; 50, 100, and 150 mg/L). Germination traits were assessed, and transcriptome sequencing was performed for the BR treatment showing the strongest promotive effect. The results demonstrate that exogenous hormones exerted distinct regulatory effects on seed germination, among which BR at 10 mg/L showed the strongest promotive effect, increasing the final germination rate at 40 d from 50% in the control to 68%, whereas higher concentrations caused inhibitory effects. Transcriptome analysis identified 169 differentially expressed genes between BR-treated seeds and the control, mainly associated with reactive oxygen species (ROS) metabolism, redox regulation, energy and carbohydrate metabolism, and plant hormone- and MAPK-related signaling pathways. Antioxidant enzyme assays showed that BR10 increased POD activity but decreased SOD, CAT, APX, and GR activities. Endogenous hormone-related analysis further revealed marked BL accumulation and significant decreases in ACC, GA₃, GA₄, IAA, JA, and SA. Overall, exogenous BR promotes seed germination of Z. schneideriana through coordinated physiological and molecular regulation, providing a useful basis for seed pretreatment and seedling propagation. Full article

Huanglongbing (HLB), primarily caused by ‘Candidatus Liberibacter asiaticus’ (CLas), threatens global citrus production. Deciphering the molecular interplay between citrus and CLas is crucial for successful control. This review synthesizes current understanding of the molecular mechanisms underlying citrus-CLas interactions, providing a comprehensive overview that spans immune signaling, hormonal and metabolic reprogramming, non-coding RNA-mediated regulation, pathogen effector biology, and emerging biotechnological interventions. We detail the hierarchical host response: initial immune recognition via pattern recognition receptors, triggering reactive oxygen species bursts and calcium signaling. Moreover, hormonal network reprogramming and their complex interplay in defense/susceptibility are examined. Transcriptomic studies have revealed key features of metabolic reprogramming, including suppression of photosynthesis and impairment of phloem function. Additionally, long-term strategies like cell wall reinforcement, accumulation of defensive compounds such as flavonoids and terpenoids, and roles of post-transcriptional regulation of microRNAs are discussed. Conversely, CLas counter-defense, notably effector-mediated immunity suppression and host metabolism manipulation, is also considered. Comparative transcriptomics between tolerant and susceptible varieties identifies tolerance or resistance genes/pathways for breeding and engineering. Despite this progress, critical knowledge gaps remain, particularly regarding the precise molecular mechanisms of CLas immune evasion and effector-mediated suppression, the genetic basis of natural tolerance, and the field-level efficacy of defense priming strategies. Future research directions should integrate single-cell omics, CRISPR/Cas9 editing, nano-enabled delivery, and microbiome engineering to bridge these gaps and accelerate HLB-tolerant/resistant citrus development. This review synthesizes how molecular profiling advances understanding of citrus defense mechanisms against HLB, and underscores the imperative for interdisciplinary research and global collaboration. Full article

Plants are constantly exposed to a wide range of abiotic stresses that have significant negative impacts on growth and yield. Plant acclimation to these stresses is governed by integrated classical phytohormone and plant peptide hormone signalling networks that control the ability of a plant to survive and adapt to extreme environments. Classical phytohormones, including abscisic acid, auxins, gibberellins, cytokinins, jasmonates, salicylic acid, brassinosteroids, and the recently recognised phytomelatonin, act in concert with peptide-based plant hormones, among which C-terminally encoded peptides (CEPs) play prominent roles in coordinating stress perception, signal transduction, and adaptive responses throughout the plant. These integrated networks control stomatal behaviour, photosynthesis, osmolyte and antioxidant levels, root architecture, and energy metabolism, thereby helping plants maintain homeostasis and optimise survival while sustaining minimal growth under unfavourable conditions. Under stressful conditions, these networks do not operate in isolation but form highly dynamic, context-dependent regulatory circuits in which each physiological process is simultaneously regulated by multiple hormones acting through convergent and overlapping signalling pathways. Phytomelatonin has emerged as a particularly important integrative node within these networks, functioning both as a potent direct antioxidant through sequential ROS-scavenging catabolite cascades and as a bidirectional regulator of classical phytohormone signalling under diverse abiotic stresses. New technologies in the fields of transcriptomics, proteomics, phosphoproteomics, metabolomics, and systems biology have provided new information on the dynamic relationships between classical phytohormones and plant peptide hormones, revealing candidate regulatory nodes and transcription factor networks that mediate stress adaptation at molecular, biochemical, and physiological levels. However, it is important to distinguish between correlative associations identified through omics profiling and causal regulatory relationships validated through rigorous genetic and biochemical experimentation, as most omics-derived candidates remain to be functionally established. Empirical studies demonstrate how these networks can be used to improve crops by increasing stress tolerance through modulating classical phytohormone and plant peptide hormone signalling, including through exogenous phytomelatonin application, CRISPR-mediated hormone pathway editing, and CEP pathway manipulation, to produce resilient cultivars without reducing yields. Although these advances represent significant progress, challenges remain, including the inherent complexity and redundancy of the networks, context-dependence and severity-dependence of hormonal responses, the persistence of a significant translational gap between laboratory findings and field application, and incomplete mechanistic understanding of peptide hormone roles under combined stress conditions. Addressing these challenges will require integrative multi-omics approaches, higher-order computational modelling, and rigorous field-based functional validation alongside emerging tools such as synthetic biology and precision breeding. Full article

Chromochloris zofingiensis, a photosynthetic microalga, has attracted considerable attention due to its ability to simultaneously accumulate lipids and astaxanthin. However, the induction of lipid and secondary metabolite biosynthesis by abiotic stress is typically accompanied by growth inhibition, resulting in a trade-off between metabolite accumulation and biomass production. In recent years, phytohormones have emerged as an effective strategy for regulating microalgal metabolism, owing to their high specificity and low effective dosage. In this study, 5-aminolevulinic acid (5-ALA) was applied under nitrogen-deficient conditions, and its effects on growth, photosynthesis, lipid metabolism, and carotenoid biosynthesis were systematically evaluated through integrated physiological, biochemical, and transcriptomic analyses. The results showed that 5-ALA had no significant effect on biomass accumulation or photosynthetic performance. However, at 2 μM, 5-ALA exhibited the strongest promotive effect on lipid and astaxanthin accumulation, with total fatty acids (TFA) and triacylglycerol (TAG) contents increasing by 13.3% and 25.7%, respectively, and total carotenoids and astaxanthin contents increasing by 15.6% and 17.2%, respectively. Under semi-continuous cultivation, TAG and astaxanthin productivities were enhanced by 13.9% and 22.9%, reaching 164 mg L⁻¹ d⁻¹ and 2.15 mg L⁻¹ d⁻¹, respectively. Transcriptomic analysis revealed that 5-ALA induced only limited transcriptional changes but enhanced glycolysis, central carbon metabolism, and nitrogen recycling, thereby increasing the supply of carbon precursors and energy. Notably, no significant transcriptional changes were observed in the carotenoid biosynthesis pathway, indicating that the enhanced accumulation of total carotenoids and astaxanthin was likely driven by increased metabolic flux. In terms of lipid metabolism, the upregulation of pathways involved in the conversion of membrane lipids into TAG, together with the downregulation of TAG degradation pathways and enhanced carbon flux, collectively promoted TAG accumulation. Overall, this study demonstrates that supplementation with 2 μM 5-ALA provides a practical and cost-effective strategy for the efficient co-production of lipids and astaxanthin in C. zofingiensis. Full article