In recent years, serotonin has been proposed as a signaling molecule in several plant physiological processes, although evidence supporting this function remains limited to date. In particular, its involvement under water deficit conditions is poorly characterised, especially regarding its mechanism of action. This study aimed to determine the implication of serotonin in the response to water stress in rocket plants through three experimental approaches: (1) analysis of endogenous concentrations of indoleamines, tryptophan, serotonin, and melatonin during the acclimation response to stress, (2) evaluation of the dose-dependent effect following its application in seedlings, and (3) analysis of the impact of serotonin application under field conditions. The results showed an increase in serotonin content under water deficit, which was negatively correlated with plant biomass and stomatal conductance, and positively correlated with abscisic acid (ABA) levels. Serotonin application in seedlings led to an improvement in plant water status in a dose-dependent manner but did not alter ABA content. By contrast, this positive effect was not observed under crop conditions. Moreover, when all datasets were integrated, tryptophan, the precursor of serotonin, exhibited a stronger correlation with ABA than serotonin. Taken together, these findings indicate that serotonin does not appear to play a central role in regulating ABA-mediated drought responses. Instead, the stronger association of tryptophan with ABA, together with its role as a precursor of indolamines and auxin, supports a more prominent role for tryptophan metabolism in the drought response than for serotonin itself.
The co-occurrence of heavy metal contamination and biodegradable microplastic (polylactic acid, PLA) pollution poses increasing risks to terrestrial plant communities and soil functioning, yet species-specific responses to combined stress remain poorly understood. Cd and microplastics frequently co-occur in agricultural soils, where microplastics can alter cadmium mobility, bioavailability, and transport pathways, potentially modifying metal toxicity and plant stress responses compared with single-pollutant exposure. We investigated the responses of the invasive Bidens pilosa and the native Solanum nigrum grown in monoculture and mixed culture under combined cadmium (Cd) and biodegradable microplastic (PLA) stress by integrating plant growth, photosynthetic performance, oxidative physiology, and rhizosphere biochemical processes. Combined Cd-MP exposure markedly reduced plant growth, chlorophyll content (SPAD), photosystem II efficiency (Fv/Fm), nitrogen accumulation, biomass production, and rhizosphere enzyme activities associated with carbon, nitrogen, and phosphorus cycling. However, B. pilosa maintained greater physiological stability under stress, characterized by higher antioxidant enzyme activities (SOD, CAT, POD), lower reactive oxygen species (H2O2, O2˙-) accumulation, and reduced lipid peroxidation (MDA), whereas S. nigrum exhibited stronger oxidative damage and functional impairment. Multivariate analyses further revealed that root antioxidant capacity was closely associated with rhizosphere microbial enzyme activity, suggesting a root-centered regulatory mechanism linking plant stress tolerance to soil functioning. Overall, the invasive species showed greater tolerance to combined contamination and maintained relatively higher rhizosphere functional activity than the native species, indicating that multi-pollutant stress may alter competitive interactions between invasive and native plants in contaminated environments.
Endophytic fungi reside within both above- and below-ground plant tissues and play pivotal roles in modulating plant fitness and immunity, particularly in the context of plant-insect interactions. They mediate plant defences through the production of bioactive compounds and the alteration of plant physiology, leading to antibiotic (affecting herbivore growth and survival) and antixenotic (deterring herbivore settlement) effects. This review synthesises current evidence on the mechanisms underlying these endophyte-mediated effects, highlighting how these interactions shape herbivore behaviour and performance. Antibiotic effects emerge through the production of secondary metabolites that disrupt herbivore digestion, development and reproduction. Simultaneously, antixenotic responses are driven by multiple mechanisms, including the synthesis of secondary metabolites, changes in plant surface chemistry and volatile emissions that reduce herbivore preference. In addition to their direct impact on herbivores, endophyte-mediated responses can influence higher trophic levels by enhancing plant attractiveness to natural enemies of herbivores, such as parasitoids and predators. These multifaceted defence strategies not only reduce herbivore damage but also contribute to broader ecological dynamics by mediating communication between above- and below-ground plant compartments. Understanding these effects is critical for advancing Integrated Pest Management (IPM) strategies, as endophytes offer a sustainable and environmentally friendly alternative to chemical pesticides.
The stimulatory effect of elevated CO2 (eCO2) on photosynthesis in most C3 crops under water deficit often declines over time due to photosynthetic acclimation. An exception occurs in plants inoculated with symbiotic nitrogen-fixing bacteria. Photosynthetic bacteria (PSB), specifically anoxygenic purple nonsulfur bacteria (Rhodopseudomonas palustris in this study), a group of nitrogen-fixing bacteria, are effective in enhancing crop photosynthesis. Therefore, this study investigated the synergistic effects of PSB and eCO2 in alleviating the effects of deficit irrigation and enhancing photosynthetic capacity in tomato plants during prolonged exposure. Our results showed that photosynthetic efficiency was significantly reduced in noninoculated plants under eCO2, and this reduction was more pronounced under water deficit. Proteomic analysis revealed that in eCO2-treated plants, the downregulation of cell wall proteins increased mesophyll resistance to CO2 diffusion, while the suppression of the photosynthetic apparatus impaired electron transport capacity, ultimately reducing CO2 assimilation efficiency. In contrast, these negative effects were alleviated by PSB inoculation. PSB promoted the upregulation of proteins involved in photosynthesis under deficit irrigation, as well as proteins related to chlorophyll biosynthesis, components of photosystem I and II, and light-harvesting complex proteins. These proteins contributed to improved photosynthetic efficiency during deficit irrigation and photosynthetic acclimation. Physiological analyses further confirmed that PSB inoculation enhanced nitrogen content, electron transport capacity, chlorophyll biosynthesis, and overall photosynthetic performance under eCO2 and deficit irrigation, resulting in improved plant growth. These findings suggest that PSB inoculation is a promising strategy to sustain and enhance the CO2 fertilization effect on crop productivity under water-limited conditions.
Functional characterization of a large number of rice genes remains a major challenge despite the availability of genome sequences and large-scale transcriptomic datasets. CRISPR-Cas9 library is a powerful approach for high-throughput targeted mutagenesis; however, its application in indica rice cultivars remains limited due to low transformation and regeneration efficiencies. In this study, we developed a CRISPR-Cas9 library targeting 12,000 rice genes and evaluated its utility for functional genomics in the indica cultivar MTU-1010. Sanger sequencing and NGS analysis of the plasmid library revealed high sgRNA coverage and more than 80% accuracy. Transformation of the developed library into the indica cultivar MTU-1010 resulted in a high target editing efficiency, with 90% of analyzed transgenic plants carrying mutations at the intended target site. Functional analysis of one homozygous mutant identified a previously uncharacterized role for OsOPR5 (LOC_Os06g11210), a member of the 12-oxophytodienoate reductase family in root architecture. The opr5 mutants exhibited significant reductions in lateral root number, seminal and crown root number, and root length, demonstrating that OsOPR5 positively regulates root system architecture in rice. Notably, endogenous jasmonic acid (JA) and JA-isoleucine levels were not significantly altered in the mutant, suggesting potential functional specialization or redundancy among rice OPR family members for JA accumulation. The root system architecture is a key determinant of water and nutrient acquisition; our results suggest that OsOPR5 may play an important role in adaptation under adverse environmental conditions. Collectively, this study establishes an efficient genome-editing platform for indica rice and identifies OsOPR5 as a novel regulator of root development.
ABSTRACT Environmental toxicity from metal oxide nanoparticles (NPs) such as yttrium oxide NPs (Y 2 O 3 NPs) poses a significant threat to crop productivity in agroecosystems. To evaluate the potential mitigating role of arbuscular mycorrhizal fungi (AMF), oat ( Avena sativa L.) and soybean ( Glycine max L.) plants were grown with or without AMF inoculation under Y 2 O 3 NP exposure conditions. Y 2 O 3 NPs caused severe growth and photosynthetic inhibition, with oat being more sensitive than soybean: shoot biomass decreased by 50%–75% in oat versus 30%–40% in soybean, and photosynthetic parameters dropped by 65%–70% in oat and 20%–35% in soybean. These effects were associated with pronounced oxidative stress, depletion of ascorbate and glutathione pools in oat, and species‐specific induction of antioxidant and phenylpropanoid pathways. Soybean maintained relatively higher photosynthetic capacity, enabling stronger upregulation of antioxidant defences (phenolics, anthocyanins) and detoxification mechanisms (phytochelatins, metallothioneins, and glutathione S‐transferase activity), reflecting a more robust thiol‐ and chelator‐based detoxification system. AMF improved growth and photosynthetic performance in both species and partially alleviated NP‐induced oxidative damage, but its protective effect was significantly stronger in soybean than in oat. Multivariate analysis showed that phenylpropanoid reprogramming and antioxidant capacity shaped species‐specific responses. These findings suggest that maintenance of physiological and redox stability plays an important role in species‐specific tolerance to Y 2 O 3 NP exposure, while AMF inoculation partially moderates stress‐related physiological and metabolic disruption.
In response to water restrictions imposed by the epiphytic environment, orchids have developed strategies to increase water-use efficiency, such as the expression of Crassulacean Acid Metabolism (CAM) and the foliar water uptake (FWU). In a climate change scenario, FWU may emerge as a strategy to reduce water stress during drought. In this study, we propose that, in Cattleya forbesii Lindl. and Cattleya guttata Lindl., drought alters the leaf water balance, increases CAM expression, and may consequently increase the FWU rate. To test this hypothesis, drought stress was induced by restricting water for 30 days in C. forbesii (n = 4) and C. guttata (n = 6). After that, we evaluated the relative water content (RWC), overnight organic acid accumulation (ΔH+), and FWU capacity. To verify the pathway of water entry into the leaves, we used the apoplastic marker Lucifer Yellow. We observed that in both Cattleya species, drought impacted leaf water status, photosynthetic activity, and FWU capacity. After water restriction, the leaf water status decreased, impairing photosynthetic activity in both species (lower RWC, potential quantum yield of PSII, and quantum efficiency under light-adapted conditions), whereas nonphotochemical quenching increased. Despite minor changes in ΔH+ values, FWU increased following drought, partially supporting our hypothesis. In both Cattleya species, LY solution diffused through the epidermis and reached the mesophyll; however, in C. guttata, this occurred only through the abaxial epidermis. These results demonstrate that FWU may serve as a strategy for Cattleya species to cope with water scarcity intensified by drought periods.
Glucosinolates in two genotypes of kale sprouts treated with methyl jasmonate (MeJA) were analyzed using ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). This approach enabled the identification of 13 distinct glucosinolates (GSLs) and the quantitative determination of their individual contents. Our results show that MeJA induced GSL biosynthesis, resulting in a significant increase in the total content of aliphatic, indolic, and aromatic GSLs, while also altering their compositional profiles. Notably, the contents of sinigrin (SIN), glucoraphanin (GRA), glucobrassicin (GBC), and glucotropaeolin (GTL) were significantly increased, accompanied by upregulation of key biosynthetic genes, including BoMYB51, BoMYB122, BoSOT18, BoST5a, and BoCYP79A2. MeJA also promoted the accumulation of total phenolics and flavonoids and enhanced CAT and POD activities, associated with improved DPPH radical scavenging activity. However, these metabolic changes were associated with significant growth inhibition, suggesting a trade-off between phytochemical enhancement and biomass production. Genotype-dependent differences were observed between the two lines, with R6 showing stronger anthocyanin induction but weaker GSL responses than W3, indicating that pre-existing metabolic background determines MeJA efficacy. These findings confirm the elicitor effects of MeJA while highlighting the need to balance growth and nutritional quality in potential applications.
Terrestrial plants are frequently exposed to fluctuating abiotic stresses throughout their life cycle, and mycorrhizae can markedly enhance host plant resistance to such challenges. This review summarizes recent advances in our understanding of how arbuscular mycorrhizal fungi (AMF) enhance host plant tolerance through multiple mechanisms. AMF promote stress tolerance through diverse mechanisms, including nutrient solubilization, polyamine accumulation, reactive oxygen species scavenging, physiological improvements, maintenance of ultrastructural stability via membrane integrity, accumulation of osmolytes such as trehalose, proline, polyamine, and glycine betaine, and activation of antioxidant enzymes to alleviate oxidative stress. While substantial progress has been made, the underlying AMF-mediated stress tolerance mechanisms remain underexplored. Future research should focus on dissecting how signaling pathways interact to regulate gene expression in mycorrhizal plants and elucidating the complex regulatory networks operating at the plant-AMF interface. We also outline key research directions for clarifying plant-AMF interactions under stress conditions, as current research highlights the use of beneficial soil microbes to mitigate stress and enhance crop resilience.
Saline-alkali soils, commonly found in coastal regions, impose substantial environmental stress on trees, affecting both growth and wood formation. The mechanisms through which trees adapt to these conditions are multifaceted, primarily involving physiological and biochemical responses. Therefore, the impact on wood properties and associated metabolic pathways warrants further exploration. Two-year-old Taxodium "Zhongshanshan302" seedlings were cultivated in salinized soil, simulating the saline-alkali ion ratio typical of a coastal mudflat. The response of wood-forming tissues to salt-alkali stress was investigated through wood anatomy techniques, cell wall chemical analysis, and metabolomic profiling. The study demonstrated that mild to moderate saline-alkali stress promoted growth, enhancing lignification and cellulose crystallinity, while severe stress led to reduced lignin synthesis and delayed tracheid lignification. Moreover, metabolite analyses suggested that severe saline-alkali stress was associated with changes in carbohydrate metabolism and phenylpropanoid-related metabolism, which may contribute to reduced cellulose deposition and lignification in "Zhongshanshan302." A distinctive mode of cellular osmotic regulation under saline-alkali stress was also delineated. The complex interplay between wood formation and saline-alkali stress responses was highlighted, providing valuable insights for tree management and wood production in affected regions.
Phyto-oxylipins, oxidized derivatives of unsaturated fatty acids, serve as crucial mediators in plant responses to biotic and abiotic stresses, which are becoming increasingly frequent and severe under changing climatic conditions. These signaling molecules, produced enzymatically or spontaneously, orchestrate a wide range of physiological and molecular responses that enhance plant resilience. By scavenging reactive oxygen species (ROS) and upregulating antioxidant enzymes, phyto-oxylipins help mitigate oxidative damage, thus preserving cellular integrity and sustaining growth under environmental stress. Additionally, they interact intricately with key phytohormones such as jasmonic acid (JA), abscisic acid, and salicylic acid (SA), forming a dynamic hormonal network that regulates stress-responsive genes and adaptive processes. Beyond stress mitigation, phyto-oxylipins promote wound healing, programmed cell death, and cell wall reinforcement, essential for maintaining plant structural integrity. Recognizing these molecules as central regulators of stress adaptation offers promising avenues for developing climate-resilient crops. This review synthesizes current insights into the molecular and physiological roles of phyto-oxylipins, emphasizing their potential in integrating plant defense mechanisms to enhance crop productivity amid abiotic and biotic challenges.
Botrytis cinerea is a devastating pathogen in viticulture, causing gray mold, and bunch rot. Under 25°C, 90% relative humidity and 36 h wetness duration, B. cinerea can lead to yield losses ranging from 20% to 50% in grapevines. This study evaluated the antifungal effects of Trichoderma afroharzianum secondary metabolite filtrates (TSMF) against the B. cinerea isolate MBc5. In vitro dual culture assays revealed that 10 T. afroharzianum isolates inhibited the colony growth of B. cinerea by 42%-88%. TSMF were collected after 30 days of incubation in yeast peptone glucose (YPG) medium and incorporated into potato dextrose agar (PDA) at 10% (v/v) for inhibition testing against B. cinerea. The filtrates significantly inhibited B. cinerea colony growth by 72%-92%. Based on these results, three highly effective isolates (Tr28, Tr138, and Tr153) were selected for in vivo assays. Leaves and bunches were inoculated with B. cinerea (1 × 106 conidia mL-1) and treated, 2 h later with TSMF (2 mL each). TSMF of Tr153 significantly reduced disease severity in leaves (52%-78%) and bunches (70.4%) compared to the pathogen control. Gas chromatography-mass spectrometry (GC-MS) analysis identified butyl acetate as the main component, constituting 39.08% of the Tr153 secondary metabolite filtrate. These results demonstrate that TSMF from T. afroharzianum has strong potential as a biological control agent against B. cinerea in grapevines.
Environmental stress, particularly salinity, reduces crop yields and poses a threat to food security. While considerable research has focused on enhancing abiotic stress resilience at the leaf surface, the mechanisms of salt tolerance at the root level, especially under varying photoperiods, remain less explored. This study examined the combined effects of salinity (80 mM NaCl), normal photoperiod (nP; 12L:12D) and extended photoperiod (eP; 22L:2D) on root metabolites in two salt-tolerant (JS7, XinChun-31) and two salt-sensitive (GS-6058, Yongliang-15) spring wheat cultivars. Control plants were grown without salt stress under a normal photoperiod. Significant differences in fresh and dry root weights were observed across conditions with salt-sensitive cultivars, especially GS-6058, exhibiting improved root growth, suggesting enhanced physiological adaptation under extended photoperiods. Metabolomic analysis using liquid chromatography-mass spectrometry identified 83 root metabolites. The salt-sensitive GS-6058 showed substantial metabolic pathway perturbations under an extended photoperiod, while salt-tolerant cultivars maintained more stable metabolic profiles. Twenty pathways were significantly impacted, with alanine, aspartate and glutamate metabolism being the most significantly altered except in XinChun-31 under eP. These results underscore the modulatory role of the photoperiod in salt stress adaptation and suggest that targeting metabolic pathway biomarkers may facilitate the breeding of wheat cultivars with improved salinity resilience. Further integration of metabolite profiling with gene expression analysis is recommended to elucidate the underlying regulatory networks driving these adaptive responses.
Pentatricopeptide repeat (PPR) proteins are key regulators of the organellar RNA metabolism in plants. However, the functions of mitochondrial PPR proteins belonging to the subclass of P-type PPR factors containing the SMR domain remain much less understood. Here, we characterize the EMBRYO DEFECTIVE 2217 (EMB2217/At1g79490), an essential PPR-SMR factor in Arabidopsis thaliana. T-DNA insertional lines at the AT1G79490 gene-locus exhibit embryonic arrest at the late heart stage and display defective germination and seedling establishment. Partial complementation using an ABI3 promoter-driven strategy enables efficient germination and the rescue of homozygous emb2217 plantlets. The pABI3::EMB2217 emb2217 -/- seedlings display severe growth defects due to impaired mitochondrial function, tightly associated with impaired OXPHOS activity. Analyses of mitochondrial RNA profiles reveal that EMB2217 is required for the processing of multiple group II introns that reside in the coding regions of several complex I (CI) subunits, the cox2 subunit of CIV, and the ribosomal rps3 factors. Our data further show that RNA maturation defects induce alternative electron transport and stress-response pathways, which are associated with developmental defects and modulation of photosynthetic and cellular metabolic processes. Together, we identify EMB2217 as a general mitochondrial splicing factor whose loss compromises OXPHOS biogenesis and function, cellular energy supply, and plant development.
Hydrogen peroxide (H2O2) is increasingly recognized as a spatially and temporally encoded redox signal, and as a trigger of oxidative stress rather than a by-product of it. In cereal crops, however, the mechanisms that convert H2O2 production into selective physiological outputs remain unevenly resolved. This review examines how H2O2 specificity arises from four interconnected layers: HPCA1-type extracellular perception, aquaporin-mediated membrane transport, thiol peroxidase-based relay chemistry, and reversible oxidative post-translational modifications (oxiPTMs). We emphasize that the functional outcome of H2O2 depends on dose, duration, compartmentation, developmental stage, and antioxidant reset capacity, especially under combined abiotic stresses and where abiotic stress alters the redox context in which pathogen attack is perceived. To distinguish established crop mechanisms from plausible but unvalidated extrapolations, the cereal literature is organized into direct mechanistic evidence, orthology-supported inference, and physiology- or association-based evidence. Rice currently provides the strongest mechanistic anchors, particularly for aquaporin-dependent H2O2 transport and glutathione peroxidase (GPX)-linked redox transduction. Wheat remains dominated by physiological and transcript-associated evidence despite high agronomic relevance, whereas maize offers trait-level priming data with limited validation of upstream perception, transport, and oxiPTM nodes. We propose that cereal H2O2 biology should move from descriptive measurements of reactive oxygen species (ROS) toward threshold-aware, tissue-resolved and evidence-tiered experimentation. Such an approach can guide candidate validation, redox-site prioritization and calibrated priming strategies without assuming that stronger ROS signaling is inherently beneficial.
Plant vascular bundles are the main pathways for the propagation of electrical signals such as action potentials (APs) and slow-wave potentials (SWPs), also known as variation potentials (VPs). Despite substantial descriptive evidence on the propagation of electrical signals, their underlying mechanisms remain elusive. Using aphids as bioelectrodes and the herbaceous Vicia faba as a biological model, we studied how physical stimuli such as cutting and burning induce propagating signals within the plants in the form of APs or VPs. Cut-induced APs were characterized by fast propagation (≈2.6 cm s-1), short duration (≈3 s), and an amplitude of about 12 mV, frequently followed by a hyperpolarization phase. In contrast, flame-triggered VPs were significantly slower (≈0.38 cm s-1), longer (≈45 s), with amplitudes comparable to APs. Notably, APs propagated at similar velocities in both acropetal and basipetal directions, whereas VPs propagated faster acropetally, suggesting different propagation mechanisms of APs and VPs. Interestingly, flame-induced VPs altered aphid feeding behavior: in 20% of cases, aphids switched from phloem ingestion (E2) to salivation (E1) within 30-320 s of signal onset, while APs did not induce any behavioral changes. This study provides the first evidence that both APs and VPs propagate through the phloem at different velocities in acropetal and basipetal directions following leaf damage. These results highlight the different functional roles that APs and VPs may play in systemic communication of external physical stimuli.
Climate change and increasing drought conditions significantly impede citrus productivity in subtropical and tropical regions. This study explores the potential of combining arbuscular mycorrhizal fungi (AMF) Funneliformis mosseae and plant growth-promoting rhizobacteria (PGPR) Pseudomonas putida to enhance drought tolerance in Citrus reticulata (Red tangerine). Although AMF-mediated drought tolerance has been extensively documented, the interactive effect of PGPR and AMF on phytohormone signalling, photosynthetic efficiency, nutrient acquisition, and gene expression remains largely unexplored in citrus. An experiment was conducted under well-watered and drought conditions to assess the physiological and molecular responses to individual and co-inoculation with PGPR and AMF. Under drought condition, dual inoculated plants showed significantly improved leaf water potential, stomatal conductance, carbon assimilation and antioxidant defence. PGPR-AMF co-inoculation enhanced chlorophyll stability, osmotic adjustment and nutrient uptake, while significantly reducing lipid peroxidation and ROS accumulation. The turquoise module emerged from transcriptomic and gene co-expression network analysis (WGCNA) as a potential key regulator of stress adaptation, revealing key regulatory transcription factors (e.g., CrMYB4, CrZFP8, CrSOS5, CrRGFR2 and CrQUA1) upregulated under combined inoculation, highlighting their potential role in stress adaptation. Our findings demonstrate that the synergistic PGPR-AMF interaction improves antioxidant enzyme activities and modulates gene expression to promote drought tolerance, providing new insights into the microbiome's role in plant resilience. These results offer a potential strategy to boost citrus growth and yield under water scarcity, with broad implications for agricultural resilience to climate change.
Vase life is a key determinant of cut flower quality and market value. Conventional vase life assessment relies on visual inspection and physiological monitoring over several days to weeks, making it labor- and time-intensive. This study introduces a rapid and noninvasive approach using plant acoustics to assess postharvest vase-life-related variation in cut chrysanthemum flowers. Six chrysanthemum cultivars were grown under two supplemental lighting treatments (Hybrid and LED) and two planting densities (54 and 74 plants m-2). Acoustic monitoring was compared with optical microscopy for the assessment of xylem vessel diameter, while conventional vase-life testing was performed in parallel. Optical microscopy validated the acoustic measurements, with both methods consistently identifying vessel radii around 10 μm. The acoustic radius ( r a ), derived from pulse settling time measurements, showed cultivar- and planting-density-specific variation. Linear mixed-effects modelling demonstrated that the relationship between acoustic radius and vase life differed significantly among cultivars, indicating that a universal relationship across cultivars is not supported. These findings show that acoustic monitoring provides a meaningful noninvasive proxy for vase-life-associated stem traits and may serve as a useful cultivar-calibrated tool for evaluating postharvest longevity in cut chrysanthemums.
Wheat stripe rust, caused by the obligate biotroph Puccinia striiformis f. sp. tritici (Pst), remains one of the most destructive fungal diseases threatening global wheat production. Beyond traditional control through chemical application and resistant cultivar breeding, rapid advances in molecular biology have substantially reshaped our understanding of the intricate molecular dialogue between wheat and Pst. In recent years, research has increasingly focused on Pst pathogenicity factors, wheat immune perception, and the multilayered signaling networks that orchestrate defense responses. Particularly, studies of the molecular crosstalk spanning PAMP recognition, effector deployment, immune activation, and host-pathogen metabolic exchanges have revealed highly dynamic and sophisticated interaction strategies employed by both organisms. A systematic overview of these molecular processes is essential for advancing host resistance breeding and for guiding the rational design of novel disease-management strategies. Here, we comprehensively synthesize current knowledge of the molecular mechanisms underlying wheat-Pst interactions, highlight key advances in understanding their reciprocal communication, and discuss emerging directions for developing durable resistance.
This study uncovers a novel concentration-dependent signaling network through which abscisic acid (ABA) modulates acid metabolism in grape berries. Treatment with 800 μM ABA significantly decreased malate and citrate synthesis and transport while enhancing glucose and fructose accumulation, optimizing the sugar-acid ratio. Multi-omics analysis revealed differential changes in 96 organic acids and identified a key malate transporter, VvALMT9. Through yeast two-hybrid screening, the VvPP2C-VvALMT9-VvSnRK2.3-VvCDPK interaction network was characterized in a dual regulatory mode. Under low-ABA conditions, VvSnRK2.3 and VvPP2C are synergistically upregulated to impair VvALMT9 function via direct binding and transcriptional repression, respectively, while reduced VvCDPK expression leads to insufficient VvSnRK2.3 phosphorylation, establishing a "low ABA-high VvALMT9" state with high acid accumulation; when low temperature is coupled with low ABA, the inactivation of the temperature-sensing domain of VvPP2C further relieves this repression, delaying acid degradation. Conversely, a high-ABA environment suppresses the basal expression of VvPP2C/VvSnRK2.3 and activates the VvCDPK-VvSnRK2.3 cascade to efficiently inhibit ALMT9 phosphorylation, blocking malate accumulation and reducing acidity. Transgenic validation demonstrated that VvALMT9 overexpression promotes acid accumulation under ambient temperature, whereas high temperature induces VvPP2C to inhibit VvALMT9, an effect reversed by ABA. Overall, this study elucidates the mechanism of ABA-temperature synergistic regulation of VvALMT9-mediated acid metabolism homeostasis, providing a theoretical basis for targeted fruit quality improvement.
