Search Results (147)

Soil salinity is a major constraint on global crop production, disrupting photosynthesis, ion homeostasis, and growth. Beyond the roles of classic osmoprotectants and antioxidant enzymes, flavonoids have emerged as versatile mediators of salt stress tolerance at the interface of redox control, hormone signaling, and developmental plasticity. This review summarizes current evidence on how salinity remodels flavonoid biosynthesis, regulation, and function from cellular to whole-plant scales. We first outline the phenylpropanoid–flavonoid pathway, with emphasis on transcriptional control by MYB, bHLH, and NAC factors and their integration with ABA, JA, and auxin signaling. We then discussed how post-synthetic modifications such as glycosylation and methylation adjust flavonoid stability, compartmentation, and activity under salt stress. Functional sections highlight roles of flavonoids in ROS scavenging, Na⁺/K⁺ homeostasis, membrane integrity, and the modulation of ABA/MAPK/Ca²⁺ cascades and noncoding RNA networks. Spatial aspects, including root–shoot communication and rhizosphere microbiota recruitment, are also considered. Based on this synthesis, we propose a flavonoid-centered stress network (FCSN), in which specific flavonoids function as key nodes that connect metabolic flux with hormonal crosstalk and stress signaling pathways. We argue that reconceptualizing flavonoids as central stress network regulators, rather than generic antioxidants, provides a basis for metabolic engineering, bio-stimulant design, and breeding strategies aimed at improving crop performance on saline soils. Full article

Microbial volatile metabolites can enhance plant growth, yet the mechanisms by which plants perceive and transduce these signals are unknown. Growth of Arabidopsis thaliana Col-0 seedlings was found to be stimulated by volatiles from the soil bacterium Streptomyces coelicolor. To investigate volatile-responding candidate signaling molecules and genes, cultivation of seedlings in gas-phase contact with S. coelicolor genotypes was combined with GC-MS and plant transcriptomics. Components potentially involved were further studied using pure compounds and A. thaliana T-DNA mutants. Application of volatiles from S. coelicolor enhanced the growth of A. thaliana seedlings primarily by stimulating lateral root growth rate and inhibiting primary root extension. Concurrently, a family-wide induction of the Kelch-repeat F-box gene family KISS ME DEADLY (KMD) was observed. A. thaliana genotypes with a loss of function for the KMD family or other alterations of auxin/cytokinin signaling homeostasis suppressed the root response to both S. coelicolor total volatiles and the common microbial volatile 3-octanone. The results reveal a novel function of KMDs in mediating plant growth stimulation in response to volatile stimulation that alters auxin/cytokinin signaling and emphasize rhizospheric microbials as potential indicators of soil status to plants. Full article

Waterlogging is a major abiotic stress that restricts plant growth, productivity, and survival by disrupting root aeration and altering hormonal homeostasis. To elucidate the physiological and molecular responses associated with flooding tolerance in Liriodendron hybrids (Liriodendron chinense × Liriodendron tulipifera), this study investigated its morphological, physiological, and transcriptomic changes under 0, 1, 3, and 6 days of waterlogging. Roots exhibited rapid decay, while leaves showed delayed chlorosis and reduced chlorophyll content. Changes in antioxidant enzyme activities reflected enhanced antioxidant capacity, with superoxide dismutase (SOD) activity decreasing and peroxidase (POD) and catalase (CAT) activities increasing. Hormone measurements indicated organ-specific patterns, including abscisic acid (ABA) accumulation in leaves and decreased indole-3-acetic acid (IAA) and gibberellin (GA) levels in both roots and leaves. Transcriptome profiling revealed extensive transcriptional adjustments in hormone biosynthesis, signaling, and stress-responsive pathways, including divergent regulation of ABA-associated genes in leaves and roots and broad downregulation of auxin- and gibberellin-related genes. Key ABA biosynthetic genes (NCED1, ABA2) and signaling components (PYL4, PP2C, ABF) were upregulated in leaves but downregulated in roots, whereas auxin (YUC6) and gibberellin (GA20ox) genes were generally suppressed. These coordinated physiological and molecular responses suggest organ-differentiated adaptation to waterlogging in Liriodendron hybrids, highlighting candidate pathways and genes for further investigation and providing insights for improving flooding tolerance in woody species. Full article

Protein post-translational modifications (PTMs), as an important biological process of plants responding to environmental stimuli, can regulate the chemical decoration and properties of translated proteins by altering amino acid side chains or protein terminal structures, thereby affecting the synthesis, assembly, localization, function, and degradation of proteins. Notably, PTMs regulate protein function without changing protein expression levels. Two dozen types of PTMs have been identified. This review summarizes the molecular mechanisms of major types of PTMs, including phosphorylation, ubiquitination, SUMOylation, glycosylation, methylation, and acetylation, with a focus on their regulatory roles in plant responses to abiotic stresses. Under heat stress, phosphorylation activates transcription factors such as HSFA1 (heat shock transcription factor 1), while SUMOylation regulates the activity of HSFA1/HSFA2 in the heat stress signaling pathway. Upon cold stress, phosphorylation, ubiquitination, and S-acylation collectively regulate the expression of cold tolerance-related genes. The drought stress response relies on SnRK2s (Sucrose 321 non-Fermenting 1-related protein kinase 2s) -mediated phosphorylation, regulation of ARF7 (auxin response factor 7) by SUMOylation, and ubiquitination. In salt stress, the coupling of phosphorylation of SOS (salt overly sensitive) pathway-related proteins, ubiquitination, and phospholipid metabolism maintains ion homeostasis. Additionally, PTMs play a key role in ABA-mediated abiotic stress responses by regulating core components of signal transduction, such as PYR (pyrabactin resistance)/PYL (PYR1-LIKE)/RCAR (regulatory components of ABA receptor) receptors, PP2Cs (protein phosphatases type 2C), and SnRK2s. On the basis of the synthesis of the regulatory mechanisms of PTMs, we discuss how PTMs can be manipulated to breed abiotic stress resilient crops and the issues to be addressed to achieve the goal, such as crosstalk between PTMs, technical challenges in investigating PTMs and identifying PTM substrates. Full article

Apyrase (nucleotide triphosphate diphosphohydrolase, NTPDase; EC 3.6.1.5) functions in a variety of plant growth and developmental processes, as well as responses to pathogens, in part, by regulating extracellular ATP (eATP) concentrations. In this study, we investigated potential roles of apyrase in the recruitment of phosphate (Pi) from extracellular nucleotides in Arabidopsis thaliana seedlings that constitutively overexpress apyrase 1 (APY1). Under Pi limitation, both WT and APY1 seedlings had decreased Pi contents and a characteristic remodeling of root system architecture (RSA). This phosphate starvation response (PSR) was prevented by the uptake of Pi released through the metabolism of extracellular NTP, which occurred at a higher rate in APY1 seedlings. APY1 seedlings had higher Pi contents than WT seedlings on Pi-sufficient media supplemented with NTP and exhibited markedly increased LR and root hair (RH) formation. Genome-wide expression profiling revealed that this expanded RSA of APY1 seedlings was correlated with the induction of >100 genes involved in regulation of auxin homeostasis, signaling, and transport, which previous studies have shown to be increased when APY1 is overexpressed. APY1 regulation of [eNTP] and purinergic signaling may thus contribute to modulation of auxin responses, resulting in enhanced uptake of Pi from the medium, including Pi released via eNTP metabolism. Full article

Flowers are key reproductive structures for many plant species. They are essential for seed and fruit production, and their development is tightly regulated by hormonal and genetic networks. The homeodomain transcription factors HAT3 and ATHB4 are known regulators of adaxial identity and hormone response. We demonstrate that flowers of the hat3 athb4 double mutant emerge at wider divergence angles relative to the wild type, a phenotype reflecting modified phyllotaxy and regulated by low auxin conditions. In addition, hat3 athb4 flowers exhibit aberrant trichome patterning on their sepals associated with enhanced sensitivity to cytokinin (CK). Through RNA-seq analysis of hat3 athb4 inflorescences, we identify the misregulation of genes involved in auxin biosynthesis (YUCCAs), auxin transport (PID), and CK metabolism (CKXs) and transport (PUPs). These findings suggest that HAT3 and ATHB4 fine-tune the auxin/CK balance and coordinate critical pattern events during reproductive development, offering new insight into hormone-mediated regulation of floral patterning. Full article

Exogenous cytokinin supply is a crucial factor during the in vitro shoot multiplication of apples. Meta-topolin has been shown to cause improved multiplication rate, higher quality in vitro shoots with better rooting, and acclimatization ability than the widely used benzyl adenine. The effects of benzyl adenine and meta-topolin on mRNA transcription in in vitro shoots were analyzed by using mRNA-seq, bioinformatics analysis, GO annotation, and KEGG mapping. The present investigations revealed that there were about 6-fold more significantly up-, or down-regulated genes (DEGs) in shoots grown on the benzyl adenine-containing medium than in those grown on the meta-topolin-containing medium. DEG analyses showed that WRKYs, bHLH, and MYB were the most affected transcription factors after both cytokinin treatments, while the expression of MIKC-type MADS-box, ERF, and AP2 transcription factors changed only after benzyl adenine treatment. DEGs related to auxin transport and signaling, as well as auxin synthesis, were differently affected by the two cytokinins. The DEG encoding cytokinin hydroxylase-like protein and related to trans-zeatin biosynthesis was up-regulated only after benzyl adenine treatment. The DEG encoding gibberellin 20 oxidase 2-like was down-regulated after a benzyl adenine supply while it was up-regulated after a meta-topolin supply. Changes in the cytokinin–auxin balance and gibberellin biosynthesis in in vitro shoots may contribute to the morphological differences previously observed for the two cytokinins. Full article

Background: Flax (Linum usitatissimum L.) is an economically important crop that is highly susceptible to Fusarium oxysporum f. sp. lini (Foln). While phytohormones are key regulators of defence, their interaction with polyamines during infection remains poorly understood. This study aimed to characterise hormonal dynamics in flax under Foln infection and the modulatory role of spermidine (Spd). Methods: Targeted UPLC–MS/MS profiling quantified over 30 hormone-related compounds, including auxins, cytokinins, gibberellins, jasmonates, salicylic acid, and abscisic acid, in shoots and roots of healthy, infected, and Spd-treated plants. Two Spd concentrations (10 and 100 mM) were applied under controlled in vitro conditions. Results: Foln infection triggered tissue- and time-specific hormonal shifts, with early activation of jasmonate and auxin metabolism in shoots and later accumulation of salicylic acid and gibberellins in roots. Spd, particularly at 10 mM, reshaped these responses by reinforcing cytokinin and salicylic acid responses, stabilising auxin homeostasis, and enhancing jasmonate and abscisic acid responses. Conclusions: Spermidine coordinates hormone crosstalk, enabling balanced and efficient defence activation. The results highlight its potential as a priming agent enhancing flax resilience to F. oxysporum. Full article

Piriformospora indica, a broad-spectrum plant growth-promoting fungus, has been successfully applied in blueberry (Vaccinium corymbosum L.). In this study, through an integrated transcriptomic and biochemical analyses, we investigated the effects of P. indica colonization on blueberry root growth under long-term tap water (EC ≈ 1500 μs/cm) irrigation. Comparative transcriptomic analysis revealed that P. indica colonization greatly influenced the expression of genes involved in RNA biosynthesis, solute transport, response to external stimuli, phytohormone action, carbohydrate metabolism, cell wall organization, and secondary metabolism pathways. Consistently, the fungal colonization significantly improved the nutrient absorption ability, and increased the contents of sucrose, starch, trehalose, total phenolic, total flavonoids, and indole-3-acetic acid (IAA), while suppressing the accumulations of jasmonic acid (JA), abscisic acid (ABA), 1-aminocyclopropane-1-carboxylic acid (ACC), and strigolactone (SL) in blueberry roots. Quantitative real-time PCR verification also confirmed the fungal influences on genes associated with these pathways/parameters, such as auxin homoeostasis-associated WAT1, cell wall metabolism-related EXP, phenylpropanoid biosynthesis-related PAL and CHS, carotenoid degradation-related CCD8, transportation-related CNGC, trehalose metabolism-related TPP, and so on. Our study demonstrated that P. indica improved blueberry adaptability to mild salt stress by synergistically regulating cell wall metabolism, secondary metabolism, stress responses, hormone homeostasis, sugar and mineral element transportation, and so on. Full article

Thigmomorphogenesis denotes a suite of anatomical, physiological, biochemical, biophysical, and molecular responses of plants to mechanical stimulation. This phenomenon is evolutionarily conserved among diverse plant lineages; however, the magnitude and character of the response are strongly determined by both the frequency and intensity of the applied stimulus. In angiosperms, thigmomorphogenetic reactions typically occur gradually, reflecting a complex interplay of morphological alterations, biochemical adjustments, and genetic reprogramming. In dicotyledonous plants, thigmomorphogenesis is commonly expressed as a reduction in leaf blade surface area, shortening of petioles, decreased plant height, radial thickening of stems, and modifications in root system architecture. In monocotyledons, in turn, mechanical stress frequently results in stem rupture below the inflorescence, with concomitant shortening and increased flexibility of younger internodes. These specific traits can be explained by structural features of monocot secondary walls as well as by the absence of vascular cambium and lateral meristems. Mechanical stimulation has been shown to initiate a cascade of responses across multiple levels of plant organization. The earliest events involve activation of mechanoresponsive genes (e.g., TCH family), followed by enzymatic activation, biochemical shifts, and downstream physiological and molecular adjustments. Importantly, recent findings indicate that prolonged mechanical stress may significantly suppress auxin biosynthesis, while leaving auxin transport processes unaffected. Moreover, strong interdependencies have been identified between thigmostimulation, gibberellin biosynthesis, and flowering intensity, as well as between mechanical stress and signaling pathways of other phytohormones, including abscisic acid, jasmonic acid, and ethylene. At the molecular scale, studies have demonstrated a robust correlation between the expression of specific calmodulin isoforms and the GH3.1 gene, suggesting a mechanistic link between mechanosensing, hormone homeostasis, and regulatory feedback loops. The present study consolidates current knowledge and integrates novel findings, emphasizing both morphological and cellular dimensions of thigmomorphogenesis. In particular, it provides evidence that mechanical stress constitutes a critical modulator of hormonal balance, thereby shaping plant growth, development, and adaptive potential. Full article

Aux/IAA genes, functioning as transcriptional regulators downstream of auxin signaling, are essential for plant growth and development. However, their roles in fruit ripening remain largely undefined in strawberry. This study aims to elucidate the role of Aux/IAA genes in strawberry ripening. We identified 22 Aux/IAA family members and performed comprehensive spatiotemporal expression and hormone response analyses. Among them, FvIAA16 and FvIAA17 emerged as strong candidates associated with fruit ripening. Transient overexpression of FvIAA16 and FvIAA17 upregulated the expression of multiple ripening-related genes, leading to anthocyanin accumulation, soluble sugar enrichment, organic acid homeostasis, and furanone production. Dual-luciferase assays further demonstrated that both proteins robustly activated the promoters of ripening-related genes such as FvCHI and FvCHS. This activation was further enhanced by dimerization of the two proteins. Collectively, these findings reveal important regulatory functions of FvIAA16 and FvIAA17 in strawberry fruit ripening and offer valuable clues for further elucidating the molecular mechanisms underlying auxin-mediated ripening regulation. Full article

MicroRNAs (miRNAs) are key post-transcriptional regulators of plant development and stress responses, with many being conserved across diverse plant lineages. In this study, we investigated the expression profiles of miRNAs and their corresponding target genes in Arachis stenosperma, a wild peanut relative that exhibits robust resistance to root-knot nematodes (RKN). Small RNA sequencing of nematode-infected roots identified 107 miRNA loci, of which 93 corresponded to conserved miRNA families and 14 represented novel candidates, designated as miRNOVO. Among these, 18 miRNAs belonging to 11 conserved families were identified as differentially expressed (DEMs). Notably, miR399 and miR319 showed the highest upregulation (logFC = 4.25 and 4.20), while miR393 and miR477 were the most downregulated (logFC = −0.83 and −0.79). Integrated analysis of miRNA and transcriptome data revealed several regulatory interactions involving key defense-related genes. These included NLR genes targeted by miR393 and miR477, hormone signaling components such as the auxin response factor ARF8 targeted by miR167, and the growth regulator GRF2 targeted by miR396. Additionally, miR408 was predicted to target laccase3, a gene involved in the oxidation of phenolic compounds, lignin biosynthesis, copper homeostasis and defense responses. Remarkably, four immune receptor genes belonging to the nucleotide-binding site leucine-rich repeat (NLR) family displayed inverse expression patterns relative to their regulatory miRNAs, suggesting miRNA-mediated post-transcriptional control during the early stages of nematode infection. These findings reveal both conserved and species-specific miRNA–mRNA modules associated with nematode resistance in A. stenosperma, highlighting promising targets for developing RKN-tolerant peanut cultivars through miRNA-based strategies. Full article

Antimony (Sb), a toxic metalloid, inhibits plant growth and threatens human health. Yellow Stripe-Like (YSL) proteins play crucial roles in metal ion transport and cellular homeostasis. While the OPT gene family has been characterized in some species, its genome-wide organization and functional involvement in Sb stress response remain unexplored in Brassica juncea. Here, we identified 47 high-confidence BjOPT genes and combined transcriptomic approaches to elucidate their regulatory roles under Sb stress. Phylogenetic tree, conserved motifs, and gene structure analyses consistently distinguished the BjOPT and BjYSL subfamilies. Comparative and collinearity analyses indicated that OPT genes in Brassica species (including B. rapa, B. nigra, and B. juncea) expanded independently of whole-genome triplication events. Transcriptomic profiling revealed significant enrichment of differentially expressed genes (DEGs) related to key biological processes (oxidative and toxic stress response, metal ion transport, and auxin efflux) and pathways (glutathione metabolism, MAPK signaling, and phytohormone transduction), highlighting their roles in Sb detoxification and tolerance. Notably, three BjYSL3 (BjA10.YSL3, BjB02.YSL3, and BjB05.YSL3) genes exhibited strong up-regulation under Sb stress. Heterologous expression in yeast demonstrated that both BjA10.YSL3 and BjB02.YSL3 enhance Sb tolerance, suggesting their potential role in transporting Sb–nicotianamine (NA) or phytosiderophore (PS) complexes. These findings advance our understanding of Sb tolerance mechanisms and provide a basis for developing metal-resistant crops and phytoremediation strategies. Full article

Given the global economic importance of citrus and growing threats from climate change and soil degradation, this study investigated how arbuscular mycorrhizal (AM) fungi (Funneliformis mosseae, Fm, formerly Glomus mosseae; Diversispora versiformis, Dv, formerly Glomus versiforme) and endophytic fungus Serendipita indica (Si, formerly Piriformospora indica) differentially enhance spring shoot growth, nutrient acquisition, phytohormone profiles, and expression patterns of Fe/Mg transporter genes in two citrus cultivars (‘Beni-Madonna’ and ‘Lane Late’). Si achieved higher root colonization than AM fungi (Fm/Dv) in both cultivars, with peak colonization observed in September. Fungal inoculation differentially enhanced spring shoot growth and leaf gas exchange, with Fm and Dv demonstrating cultivar-specific effects, while Si consistently increased shoot number across cultivars but showed limited gas exchange influence in ‘Lane Late’. In ‘Beni-Madonna’, AM fungi broadly enhanced auxins/cytokinins, while Si specifically increased indole-3-acetic acid and dihydrozeatin but reduced N⁶-isopentenyladenine; ‘Lane Late’ showed comprehensive hormone upregulation by all fungi except Si’s dihydrozeatin suppression. AM fungi enhanced Ca, Mg, and Mn in ‘Beni-Madonna’ and P, S, Zn, and B in ‘Lane Late’, while Si increased Fe and Zn in the former and P, S, and B in the latter. Fungal symbionts differentially regulated Fe/Mg transporter genes in a cultivar-specific manner. In ‘Beni-Madonna’, Fm upregulated key Fe transporters (CsFRO1, CsHA1, and CsIRT1) while Si broadly enhanced all Fe transporters, correlating with increased leaf Fe levels; Fm specifically induced CsMGT2 and CsMGT8, showing strong association with Mg accumulation. ‘Lane Late’ exhibited distinct responses, with Si comprehensively activating both Fe (CsFRO1, CsHA1-2, and CsIRT1-2) and Mg (CsMGT6/8) transporter genes, while Dv showing minimal effects. These findings demonstrate that fungal symbionts differentially regulate citrus growth and nutrient homeostasis in a cultivar-dependent manner, highlighting the importance of host genotype-specific fungal partnerships for sustainable citrus production. Full article

Dongxiang wild rice (DXWR, Oryza rufipogon Griff.), the northernmost known wild rice species, exhibits exceptional tolerance to combined low-temperature and anaerobic stress during seed germination, providing a unique model for understanding plant adaptation to complex environmental constraints. Here, we employed an integrated multi-omics approach combining genomic, transcriptomic, and metabolomic analyses to unravel the synergistic regulatory mechanisms underlying this tolerance. Genomic comparative analysis categorized DXWR genes into three evolutionary groups: 18,480 core genes, 15,880 accessory genes, and 6822 unique genes. Transcriptomic profiling identified 10,593 differentially expressed genes (DEGs) relative to the control, with combined stress triggering the most profound changes, specifically inducing the upregulation of 5573 genes and downregulation of 5809 genes. Functional characterization revealed that core genes, including DREB transcription factors, coordinate energy metabolism and antioxidant pathways; accessory genes, such as glycoside hydrolase GH18 family members, optimize energy supply via adaptive evolution; and unique genes, including specific UDP-glycosyltransferases (UDPGTs), confer specialized stress resilience. Widely targeted metabolomics identified 889 differentially accumulated metabolites (DAMs), highlighting significant accumulations of oligosaccharides (e.g., raffinose) to support glycolytic energy production and a marked increase in flavonoids (153 compounds identified, e.g., procyanidins) enhancing antioxidant defense. Hormonal signals, including jasmonic acid and auxin, were reconfigured to balance growth and defense responses. We propose a multi-level regulatory network based on a “core-unique-adaptive” genetic framework, centered on ERF family transcriptional hubs and coordinated through a metabolic adaptation strategy of “energy optimization, redox homeostasis, and growth inhibition relief”. These findings offer innovative strategies for improving rice stress tolerance, particularly for enhancing germination of direct-seeded rice under early spring low-temperature and anaerobic conditions, by utilizing key genes such as GH18s and UDPGTs, thereby providing crucial theoretical and technological support for addressing food security challenges under climate change. Full article