Wheat stripe rust is a devastating disease caused by Puccinia striiformis f. sp. tritici (Pst), which seriously threatens the safety of wheat production in China. The pathogenesis-related protein-1 (PR1) gene is important for plants to respond to various biotic and abiotic stresses. In this study, TaPR1-66 was selected as a candidate gene based on previous gene family identification and transcriptome sequencing analysis. Virus-induced gene silencing indicated that TaPR1-66 positively regulated wheat stripe rust resistance. Subcellular mapping indicated that TaPR1-66 was located in the periphery. This study preliminarily verified that TaPR1-66 positively regulated wheat XC32 resistance to stripe rust, which provided a theoretical basis for the mining of resistance genes and the creation of new germplasm materials.
Chinquapin (Castanea henryi) is an important nut-producing tree species in southern China. Symbiosis with ectomycorrhizal fungi (EF) can promote nutrient absorption, which is correlated with colonization rate (CR). Lateral roots (LR) development is a precursor of ectomycorrhizal formation, and exogenous indole-3-butyric acid (IBA) is known to promote LR development. However, it is still not known whether IBA application increases ectomycorrhizal CR and improves nutrient absorption. Also, how do host plants respond to exogenous IBA at the physiological and gene levels is still not clear. To eliminate the influence of fungal growth rate on symbiosis, we selected a strain of EF (LY-9, Scleroderma citrinum 1) whose growth was unaffected by exogenous IBA, and determined the optimal concentration of IBA that promotes LR development. Results indicated that (1) exogenous IBA did not significantly increase CR; (2) both IBA application and EF inoculation enhanced seedling height, root collar diameter, biomass, and root tips. Notably, EF inoculation had a greater promoting effect on seedlings N, P, and K uptake than IBA addition. EF inoculation increased IAA, IBA, and GA3 content while reducing ABA content in roots and leaves. However, IBA uniquely reduced strigolactone (SLs) content in roots without affecting ABA or GA3; (3) both IBA addition and EF inoculation downregulated the auxin response factor ChARF18, but only EF induced upregulation of the symbiotic signaling gene ChNORK. These results indicated that exogenous IBA does not enhance EF colonization rate, and that both exogenous IBA and EF improve plant growth, albeit via different physiological and molecular strategies.
Floral nectar sugar composition is a key trait underlying plant–pollinator interactions and honey production, yet the molecular basis of natural variation in nectar sugar accumulation remains poorly understood in woody nectar-producing species. Tilia amurensis is an important nectar-producing tree species in northeastern China and provides a valuable system for investigating provenance-dependent variation in nectar sugar accumulation. Here, nectar sugar composition was characterized across four T. amurensis provenances, followed by integrated transcriptomic and metabolomic analyses of contrasting high- and low-sugar provenances. High-performance liquid chromatography identified fructose, glucose, sucrose, and maltose in nectar, with fructose and glucose predominating. Nectar sugar composition varied significantly among provenances, with WY and LSH generally showing higher levels of major sugars, whereas RH consistently exhibited the lowest levels of all four measured sugars. Transcriptomic comparison between WY and RH identified 14,513 differentially expressed genes, including 7,577 upregulated and 6,936 downregulated genes. Integrated analyses highlighted carbohydrate metabolism and sugar transport-related pathways associated with provenance-dependent differences in nectar sugar accumulation. SWEET9 and SUT4 exhibited differential expression patterns consistent with variation in nectar sugar accumulation. These findings identify candidate metabolic pathways and sugar transporters associated with nectar sugar variation and provide a multi-omics resource for generating hypotheses regarding the molecular basis of nectar sugar accumulation in this woody nectar-producing species.
12-oxo-phytodienoic acid (OPDA), a biosynthetic precursor of jasmonic acid (JA), also functions as a signaling molecule and has been implicated in stomatal regulation. However, the molecular mechanisms underlying OPDA-induced stomatal closure remain largely unclear. Here, we demonstrate that exogenous OPDA induces stomatal closure without strict dependence on canonical JA or abscisic acid (ABA) biosynthesis and signaling pathways, as evidenced by analyses of multiple JA- and ABA-related mutants in Arabidopsis thaliana. Exogenous OPDA treatment also promoted hydrogen peroxide (H2O2) accumulation in guard cells. Notably, the NADPH oxidase respiratory burst oxidase homolog protein F (RbohF), but not RbohD, was required for OPDA-induced reactive oxygen species (ROS) production and stomatal closure. Furthermore, disruption of extracellular calcium ion (Ca2+) availability or influx significantly impaired OPDA-induced stomatal closure, indicating that Ca2+ influx is an essential component of this response. In addition, the OPDA-binding protein RESISTANT TO CORONATINE 4 (ROC4) was required for OPDA-triggered H2O2 accumulation and stomatal closure, suggesting that ROC4 functions upstream of ROS production during OPDA-induced stomatal closure. Transcriptomic analysis of OPDA-treated OPDA reductase 3 (OPR3) and CORONATINE INSENSITIVE 1 (COI1) double mutant opr3/coi1-30 ice-blended epidermal fragments containing guard cells identified a limited set of OPDA-responsive genes associated with transcriptional regulation, redox homeostasis, detoxification, and stress-related signaling pathways. Collectively, these results indicate that exogenous OPDA promotes stomatal closure through a signaling module involving ROC4-dependent activation of RbohF, ROS production, extracellular Ca2+ influx, and demonstrate that OPDA-mediated stomatal regulation can occur without strict dependence on canonical JA and ABA pathways under the tested conditions.
Oryza coarctata is the only halophytic relative in the genus Oryza (Oryza sp.) that is tolerant to high salinity levels lethal to cultivated rice varieties. An excessive accumulation of reactive oxygen species (ROS) caused by salinity leads to oxidative stress, although certain ROS also play important signaling roles. This work investigated differences in root redox and ionic homeostasis between cultivated (O. sativa) and wild (O. coarctata) rice species. Root treatment with 10mM H2O2 decreased cell viability in cultivated but not wild rice, and histochemical staining showed greater H2O2 accumulation in wild rice roots under non-saline conditions, suggesting a signaling role. Wild rice showed higher superoxide dismutase (SOD) activity that lowers superoxide (O2-) accumulation. Cultivated rice showed greater K+ loss from the root mature zone through ROS-activated cation channels accompanied by stronger Ca2+ uptake in response to H2O2 application, while wild rice possessed better Ca2+ homeostasis with less H2O2-induced K+ leakage. Cultivated rice also demonstrated much higher sensitivity to hydroxyl radicals (●OH). Wild rice effectively controlled cytosolic Ca2+ homeostasis by Ca2+ efflux systems such as Ca2+-ATPase and CAX, while cultivated rice downregulated RBOH expression that may affect operation of the “ROS-Ca2+ hub” and signaling cascades under salinity.
In cigar tobacco, light and temperature are fundamental regulators of leaf development and carbon allocation, yet their combined effects on secondary vein lignification and vascular architecture remain poorly understood. This study investigated how contrasting light and temperature regimes regulate secondary vein development and lignification by integrating anatomical, metabolomic, and transcriptomic analyses. Plants were grown under four regimes combining high or low light (HL/LL) with high or low temperature (HT/LT): HLHT (600 μmol m⁻² s⁻¹, 30°C), LLHT (300 μmol m⁻² s⁻¹, 30°C), HLLT (600 μmol m⁻² s⁻¹, 20°C), and LLLT (300 μmol m⁻² s⁻¹, 20°C). Among these treatments, LLHT most strongly suppressed vascular development, reducing secondary vein diameter by 3–12% and lignin content by 22–26% relative to the other treatments. This response was accompanied by reduced accumulation of monolignol precursors and declines in phytohormones associated with growth and lignification (cytokinin, jasmonate, and salicylic acid), alongside elevated ethylene precursor (ACC). Dissociation between L-phenylalanine availability and monolignol production under LLHT indicated that phenylpropanoid flux suppression occurs at post-entry enzymatic steps rather than through substrate limitation. Time-resolved transcriptomic analysis revealed progressive repression of phenylpropanoid and lignin biosynthetic genes under LLHT, whereas low temperature (LT) partially alleviated the inhibitory effects of low light (LL). WGCNA identified contrasting lignification-associated modules, including a positively correlated module containing COMT, SUS, ARR-A, and IAGLU genes, linked to carbon allocation and hormone-associated secondary wall reinforcement; and a negatively correlated module containing TMK, PYL, grxC, and EREBP genes, associated with signaling and stress-related processes, and activated under LLHT. Collectively, these findings show that combined light and temperature regimes drive coordinated metabolic and transcriptional reprogramming underlying vascular lignification and secondary vein plasticity in cigar tobacco.
Biogenic volatile organic compounds (BVOCs) are critical for plant flavor quality, growth, and stress resistance, yet they remain poorly characterized in wheat. In this study, we performed volatile metabolome analysis on six wheat cultivars under normal and stress environments. A total of 476 BVOCs were detected, including esters, heterocyclic compounds, terpenoids, and other classes. Two-dimensional partial least squares-discriminant analysis (PLS-DA) effectively discriminated wheat samples from different environments, but failed to separate different cultivars. Notably, cultivars displayed distinct responses to stress. Certain cultivars exhibited low baseline BVOC levels but strong inducibility under stress, whereas others showed minimal BVOC variation. Terpenoids, particularly monoterpenes, were the most induced BVOC class across most cultivars, even in those stress insensitive cultivars. Transcriptomic profiling and co-expression network analysis identified gene modules correlated with total and specific BVOCs, which were enriched in genes involved in stress responses, sugar signaling, hormone signaling, and regulatory processes of gene expression. By integrating the expression profiles of core enzymes from four major BVOC biosynthetic pathways, we observed a decoupling between gene expression and BVOC variation. Further analysis focusing on monoterpene biosynthesis revealed that rate-limiting enzymes were up-regulated only in few cultivars, whereas the expression of genes involved in reducing power generation and carbon competition aligned with monoterpene variation. Functional assays demonstrated that among the co-upregulated BVOCs, 1,3-propanediol application promoted seedling growth under both normal and drought conditions, while 4-aminopyridine pretreatment enhanced potassium retention under salt stress. Collectively, our study provides novel insights into the mechanisms and functions underlying BVOC synthesis in wheat under stress.
Tropospheric ozone is a secondary air pollutant that negatively affects plant growth, but its impact on seed germination remains poorly understood despite the occurrence of ozone episodes in early spring. This study investigated the direct effects of ozone exposure on non-dormant seed germination, together with the impact on the key phytohormones that govern germination. We exposed seeds of five widely distributed temperate tree species (Pinus sylvestris, Betula pendula, Alnus glutinosa, Acer pseudoplatanus, and Picea sitchensis) to elevated (+ 60 ppb) or ambient atmospheric ozone concentrations over 27-day germination periods. Elevated ozone led to a significant delay and reduction in germination (by 17%) in P. sylvestris, with the same but weaker trends in B. pendula and P. sitchensis, and no detectable effects in A. glutinosa or A. pseudoplatanus. At the end of the trial, ozone altered the balance of the key germination-regulating hormone abscisic acid (ABA; 1.5-fold change) in ungerminated P. sylvestris seeds, as well as the levels of hormones that influence ABA transcription (auxin; 9-fold change) and plant responses to abiotic stress (jasmonic acid; 3-fold change; salicylic acid; 2-fold change). These phytohormonal effects provide a suggested mechanism through which ozone can induce changes in seed germination, with species sensitivity likely depending on oxidant uptake, antioxidant capacity and physical seed characteristics. Our results underscore ozone's potential role as a selective pressure by differentially affecting seed germination dynamics.
Increasing soil salinity is considered one of the major threats to the sustainability of vineyards in semi-arid regions, including Iran. Therefore, developing strategies to enhance plant tolerance to salt stress (SS) is essential. In this context, foliar application of ascorbic acid (AA) can effectively mitigate the adverse effects of SS. In this study, two grapevine cultivars, Sultana (Su) and Yaghouti (Ya), and two rootstocks, 140 Ruggeri (Ru) and 1103 Paulsen (Pa), were evaluated under SS (0, 25, and 50 mM NaCl) and different concentrations of AA (0, 2, 4, and 6 mM). The leaf-related traits assessed included parameters associated with the antioxidant defense system, malondialdehyde (MDA) accumulation, ionic–mineral interactions, and hormonal responses. SS increased MDA content and the accumulation of sodium (Na⁺) and chloride (Cl⁻), while reducing potassium (K⁺), calcium, and magnesium concentrations in leaves. The rootstocks Ru and Pa exhibited a greater ability to restrict Na+ and Cl– uptake and maintain ionic homeostasis compared with the Ya and Su cultivars. Foliar application of AA, particularly at 6 mM, enhanced the activities of superoxide dismutase, catalase, and ascorbate peroxidase and increased total phenolic content. This treatment also promoted the accumulation of indole-3-acetic acid, abscisic acid, salicylic acid, and jasmonic acid, especially in the Ru and Pa rootstocks. Moreover, multivariate analyses clearly differentiated the rootstocks and cultivars in their responses to SS and AA treatments. Overall, the results demonstrate that AA enhances grapevine tolerance to salinity through coordinated regulation of hormonal balance, ionic homeostasis, and antioxidant defense systems.
Bermudagrass is one of the most extensively cultivated turfgrass and forage grass, exhibiting strong tolerance to submergence stress. However, the underlying mechanism remains largely unexplored. Here, the transcriptome profiles combined with physiological and biochemical analyses were conducted to investigate the responses of bermudagrass to submergence stress. The growth of bermudagrass was gradually inhibited with enhanced antioxidant enzyme activities as submergence duration increased. Transcriptome analysis showed numerous unigenes were differentially expressed in bermudagrass under 7 d and 14 d submergence stress. Protein-protein interaction (PPI) network of 149 differentially expressed genes/unigenes (DEGs) in roots identified 5 hub genes related to ethanolic fermentation, including 4 unigenes encoding pyruvate decarboxylase (PDC) and 1 unigene encoding alcohol dehydrogenase (ADH). GO enrichment analysis suggested that most of GO terms within the biological process category were associated with cell wall in roots but not in shoots. Moreover, detailed expression profiling of DEGs associated with cell wall biosynthesis, assembly and modification was analyzed. Paraffin sections of roots, stems and leaves showed that cell wall lignification and suberization were enhanced with prolonged submergence treatment. Measurements of cell wall components revealed that root pectin content increased progressively with prolonged submergence, whereas lignin content showed no significant change except at 14 days of submergence. In contrast, root cellulose and hemicellulose contents declined. Among the DEGs, one DEG CdPGIP1, which encodes a cell wall protein of polygalacturonase-inhibiting protein, was selected and cloned. Heterogeneous overexpression of CdPGIP1 in Arabidopsis enhanced its tolerance to submergence stress with increased survival rate and dry weight after water recedes from submergence. Collectively, these findings suggest that bermudagrass may adapt to submergence stress through the regulation of both ethanolic fermentation and cell wall remodeling. Our results provide valuable information for breeding submergence-resistant plants through gene manipulation in the future.
Numerous woody plants regenerate shoots from roots and stumps after aboveground damage. Frequent disturbances (herbivory, cutting) in desert ecosystems make resprouting critical for plant survival and ecosystem sustainability, yet the adaptive mechanism of new shoots remains unclear. We measured leaf water potential, photosynthesis, and quantified water sources of four desert shrubs. The results showed that resprouting plants did not shift the root water uptake sources. Calligonum mongolicum, Hedysarum scoparium, and Tamarix chinensis mainly relied on deep soil water and groundwater, with a conservative water-use strategy. While Zygophyllum xanthoxylum displayed remarkable plasticity, switching between shallow and deep sources in response to seasonal changes and precipitation events. Specifically, following precipitation, its shallow use proportion increased sharply from 12%∼14% to approximately 50%. Compared with control plants, resprouting plants exhibited significantly higher leaf water potential (p < 0.05), photosynthetic rate, and transpiration rate. These findings suggest that resprouting shrubs adopt a prioritized recovery strategy in water transport and utilization, which confers a competitive advantage and promotes rapid regeneration. The change in water sources regulated stomatal conductance to coordinate the balance between carbon assimilation and water consumption, thereby affecting the water use efficiency of plants and overall water adaptability. Finally, the findings revealed that desert plants can rapidly regrow by competing for limited resources such as water and nutrients following external disturbances. This effectively enhanced the self-repairing potential of the damaged desert communities, maintained the stability of species diversity, and provided a scientific basis for the vegetation restoration and ecological restoration in arid areas.
Drought threatens global crop production. Pearl millet (Pennisetum glaucum L.), a naturally stress-tolerant C4 cereal, offers an ideal system to dissect genetic adaptation to abiotic stress. While CCCH proteins play key roles in plant stress responses, functions of specific CCCH genes in pearl millet remain underexplored. Here, we identified 53 CCCH genes in the pearl millet genome. Expression profiling revealed seven clade I members that respond to multiple stresses; we selected one, PgC3H50, for functional analysis. Heterologous overexpression of PgC3H50 in Arabidopsis thaliana conferred increased leaf water retention, decreased electrolyte leakage, and upregulated expression of DREB2A/B and downstream marker genes (RD29A, RD29B, RAB18). Mechanistically, we discovered that the ABA-responsive transcription factor PgAREB1 (abscisic acid-responsive element-binding protein 1) could bind to ABRE cis-elements in the PgC3H50 promoter and activate its transcription. This study reports the first functional characterization of a CCCH gene in pearl millet and uncovers a previously unknown putative PgAREB1–PgC3H50 regulatory module embedded in the ABA-mediated signaling cascade. Our findings provide a compelling genetic target for precision breeding of drought-stress-tolerant cereals.
CLS (Cercospora leaf spot) of Sugar beet (Beta vulgaris L. ssp. vulgaris) seriously restricts sugar crop production, and its molecular mechanism underlying disease resistance remains to be elucidated. In this study, a transcription factor BvMYB108 was identified from sugar beet, which interacts with three ethylene-responsive factors, namely BvERF3/4/5, in the cell nucleus. After pathogen infection, the expression of BvERF4/5 is up-regulated while that of BvERF3 is down-regulated, but all three factors exhibit consistent regulatory effects on downstream target genes when co-expressed with BvMYB108. Dual-luciferase reporter assays demonstrated that BvMYB108 alone activates the lignin biosynthesis gene BvPAL and inhibits the chitinase genes BvCHIB1/8; when co-expressed with BvERF, BvMYB108 inhibits BvPAL and activates BvCHIB1/8. BvMYB108 does not contain an EAR repression motif, and its inhibitory function may be achieved through competitive binding or recruitment of co-repressors, with protein interaction mediating the functional switch. Physiological assays showed that jasmonic acid (JA) content increases, 1-aminocyclopropane-1-carboxylic acid (ACC) content decreases slightly, and lignin accumulation increases in resistant sugar beet varieties. This study reveals that the BvMYB108‑BvERF complex fine-tunes the regulation of CLS resistance in sugar beet by switching the transcriptional output of physical and chemical defense pathways, providing novel gene resources for disease-resistant breeding of sugar beet.
Drought stress critically limits crop production and threatens global food security. Despite significant efforts to alleviate drought stress through foliar applied zinc oxide nanoparticles (ZnO NPs), their stage-specific efficacy and underlying physiological mechanisms under varied soil moisture remain poorly understood. Therefore, we systematically investigated the effects of foliar application of ZnO NPs at 50 and 100 mg L−1 during the heading and grain filling stages on leaf photosynthetic, hydraulic, and physiological‑biochemical traits in wheat (Triticum aestivum L.) under mild (W1, 65%–75% field capacity) and severe (W2, 50%–60% field capacity) deficit irrigation conditions. The results showed that under W2 condition the net photosynthetic rate, stomatal conductance, leaf water potential, plant hydraulic conductance decreased significantly, while abscisic acid (ABA), soluble sugars, and proline increased sharply during the heading stage of wheat. Foliar application of 100 mg L−1 ZnO NPs during this stage effectively alleviated drought‑induced photosynthetic inhibition, by reducing ABA content, normalizing osmotic potential via down-regulation of stress induced proline and soluble sugar over accumulation, and then promoting the stabilization of predawn leaf water potential. In contrast, during the grain filling stage, strategies relying solely on leaf protection exhibited limited potential for improving photosynthesis and drought resistance. Furthermore, under W2 conditions, the application of ZnO NPs significantly increased the zinc content in stems, leaves, and grains on a dry matter basis at maturity. These findings clarify that foliar ZnO NPs alleviate drought stress primarily during the heading stage by modulating ABA signaling, osmotic adjustment, and antioxidant defense, thereby improving leaf water status and photosynthesis. This study provides a physiological basis for the stage-specific application of ZnO NPs in wheat under water-limited conditions.
Nitrogen (N) is one of the main limiting nutrients in crops, and continuous low temperature (LT, 15 °C/8 °C, day/night) significantly inhibits crop photosynthesis. However, it remains unknown how N supply affects leaf N allocation and anatomical structure coordinate gm adaptation to LT. Consequently, we determined leaf gas exchange and fluorescence, leaf N allocation and anatomy of Bonai 526 and Jinyou No.1 cucumber seedlings to N supplies under LT and normal temperature (NT) by using hydroponic experiments. A Regression analysis and a structural equation model were used to investigate relationships among structural characteristics, N forms and mesophyll conductance (gm). LT reduced the total N content per unit leaf area (Na) and nonprotein N (Nnp) content, decreasing chloroplast surface area exposed to intercellular air spaces per leaf area (Sc/S), which increased CO2 diffusion resistance in the liquid phase (rliq). This resulted in decreased gm, inhibiting photosynthesis. Under LT, different leaf N forms had significant direct effects on Sc/S; moreover, the effect of Sc/S on the liquid-phase conductance was greater than that of rliq. The effect of N supply on gm and photosynthesis of cucumber was cultivar dependent, higher N supply could not maintain photosynthetic capacity of Bonai 526 under LT. Jinyou No.1 had higher photosynthetic capacity, Sc/S, contents of Na, water-soluble protein N and Nnp, and lower rliq and sodium dodecyl sulfate-soluble protein N contents under 7 mM N supply at LT. These findings suggest that N supply is associated with improved carbon dioxide transport and photosynthetic capacity in Cucumis sativus L. by regulating N allocation and mesophyll structure under LT.
Cadmium contamination in agricultural systems threatens both crop productivity and food safety. Although calcium and ethylene signaling pathways are recognized as key mediators of plant stress adaptation, their hierarchical organization and coordinated function in cadmium tolerance remain poorly understood. In this study, we demonstrate that cadmium stress in Arabidopsis activates a calcium‑dependent transcriptional cascade that promotes ethylene biosynthesis and signaling, ultimately leading to the suppression of root elongation. Pharmacological inhibition of calcium signaling enhanced plant tolerance to cadmium, indicating its negative regulatory role in the cadmium response. Transcriptomic profiling and ethylene‑responsive reporter assays revealed that ethylene acts as a downstream transcriptional target of calcium signaling under cadmium stress. Genetic epistasis analyses further established the functional hierarchy: disruption of calcium signaling improved root tolerance, whereas exogenous restoration of ethylene signaling reversed this phenotype, confirming ethylene as a critical downstream component. Molecularly, this calcium–ethylene regulatory module coordinated the expression of genes involved in cadmium transport, including the down-regulation of the uptake-related gene IRT1 and the xylem-loading gene HMA4, alongside the up-regulation of the vacuolar sequestration-related gene MTP1. Our findings define a previously uncharacterized calcium‑ethylene signaling axis that links environmental cadmium perception to the metal homeostasis, providing a mechanistic framework for engineering crops with reduced cadmium accumulation.
Soil salinization represents a significant environmental challenge that adversely affects the growth and productivity of wheat (Triticum aestivum L.), primarily by impeding root development. Although melatonin (MT) is acknowledged as a crucial phytohormone involved in responses to abiotic stress, the precise mechanisms through which endogenous MT facilitates salt tolerance in wheat roots remain inadequately elucidated. In this study, we observed that salinity stress induces a rapid accumulation of endogenous MT in wheat roots, which is associated with a marked upregulation of the biosynthetic gene TaCOMT. Heterologous overexpression of TaCOMT in Arabidopsis resulted in significantly elevated MT levels and conferred enhanced salt resistance, as evidenced by increased root biomass and length. Mechanistic investigations indicated that MT functions upstream of hydrogen sulfide (H2S) signaling. MT treatment prompted a surge in endogenous H2S production by enhancing the activity of the biosynthetic enzyme L-cysteine desulfhydrase. Pharmacological interventions revealed that the protective effects of MT, particularly in restoring redox homeostasis and maintaining ion balance, were nullified by the removal of H2S. Collectively, these findings suggest a critical role for MT in modulating salt tolerance through H2S signaling pathways.
Cadmium (Cd) contamination of agricultural soils presents a threat to global food security and human health. Cereal crops, which serve as sources of dietary calories and protein, represent the primary pathway for Cd exposure for millions of individuals. This review offers an assessment of multi-omics advancements and biotechnological innovations that elucidate the molecular mechanisms underlying Cd uptake, transport, detoxification, and tolerance in major cereal crops, including rice, wheat, maize, barley, sorghum, and millet. The analysis encompasses conserved and species-specific transporter networks, such as the NRAMP, ZIP, HMA, LCT, and OsCd1 families, alongside regulatory pathways that govern long-distance Cd translocation and grain accumulation. This examination highlights promising molecular targets for breeding low-Cd varieties and implementing phytoremediation strategies. Furthermore, the review discusses cellular detoxification mechanisms, including phytochelatin (PC)- and metallothionein (MT)-mediated chelation, vacuolar sequestration, antioxidant defenses, and epigenetic regulation, within the context of complex hormonal interactions that influence Cd homeostasis. Additionally, the review evaluates innovative interventions, such as CRISPR/Cas9-mediated editing of key transporters, marker assisted and genomic selection, microbiome-based strategies, and phytoremediation approaches aimed at reducing Cd accumulation without compromising yield or grain quality. Despite significant advancements, substantial gaps remain, particularly concerning the field validation of genome-edited lines, the equilibrium between Cd exclusion and micronutrient retention, and the functional characterization of underexplored transporters in cereals. By integrating mechanistic insights with next-generation breeding, genome engineering, and sustainable soil management practices, this review proposes a strategic framework to facilitate the development of Cd-safe cereal varieties that are essential for global food safety and current environmental variability.
Vapor pressure deficit (VPD) is a key driver of leaf transpiration and plays a crucial role in regulating water transport in plants. Elevated VPD often induces morphological, physiological, and biochemical responses that can impact plant performance and crop yields. This study aimed to investigate the genetic variability of oil palm responses to high VPD through two controlled experiments. Six oil palm progenies at an early growth stage were evaluated under low and high VPD conditions in glasshouses with tightly regulated air temperature, humidity, and irrigation to maintain non-limiting soil moisture, isolating the effects of VPD from soil water deficit. Phenological, morphological, ecophysiological, biochemical, and candidate gene expression analyses were conducted to assess progeny-specific responses.The results revealed distinct morphological differences in leaf traits among progenies that remained consistent under both VPD treatments, although total leaf area was similar across progenies. Significant effect of VPD on daily evapotranspiration was observed during both years, while the progeny effect was either absent or minimal. To limit water loss under high VPD, progenies reduced stomatal conductance, demonstrating a common adaptive response to elevated VPD. Biomass allocation patterns were progeny-specific and, along with carbon assimilation rates, remained stable regardless of VPD level. However, one progeny (G02) exhibited distinct behavior, with both stomatal conductance and water use efficiency not affected under high VPD, and a greater plasticity on carbon allocation to leaves.Overall, our results identify clear between-progeny morphological diversity and emerging progeny-specific responses to high VPD, but do not yet identify a single juvenile trait that reliably predicts whole-plant response.
