Search Results (1,706)

Sweet and sour flavors are the most important indicators of loquat fruit quality; they are determined not only by variety but also by the flesh type and the concentration and change patterns of sugars, organic acids, related enzyme activities, and endogenous phytohormones. This study aimed to comprehensively evaluate the physiological and biochemical characteristics associated with loquat fruit flavor formation by analyzing the changes and correlation in sugars, organic acids, enzyme activities, and endogenous hormones during fruit development in the white-fleshed, high-sugar cultivar ‘Qixing’ and the red-fleshed, sour–sweet cultivar ‘Huoju’. The results indicated a significant increase in total soluble sugars and individual sugars (mainly fructose, glucose, and sucrose), and a sharp decrease in organic acids (mainly malic acid). Correlation analysis revealed that the activities of sucrose synthase (SS), sucrose phosphate synthase (SPS), and phosphofructokinase (PFK) were positively associated with sugar accumulation. In contrast, phosphoenolpyruvate carboxylase (PEPC), NADP-malic enzyme (NADP-ME), and NAD-malate dehydrogenase (NAD-MDH) were crucial for organic acid metabolism. Phytohormone analysis indicated that indole-3-acetic acid (IAA) and gibberellic acid (GA3) play vital roles in fruit enlargement, while abscisic acid (ABA) is important for fruit ripening in loquats. These findings provide insights into the physiological mechanisms underlying loquat fruit quality formation, reveal the enzymatic or hormonal regulatory effects on sugar accumulation and acid degradation, and provide a theoretical basis for improving the fruit flavor quality. Full article

Abscisic acid (ABA) and ethylene are both essential regulators of strawberry fruit (Fragaria × ananassa Duch.) ripening. This study investigated the interplay between ABA and ethylene, revealing that ABA downregulates FaMADS1, thereby de-repressing ethylene biosynthesis genes. Functional validation via FaMADS1 silencing and over-expression confirmed that FaMADS1 acts as a negative regulator of ethylene biosynthesis key genes (FaSAMS1, FaACS1, and FaACO1). Furthermore, dual-luciferase assays demonstrated FaMADS1’s direct suppression of the promoters of key ethylene biosynthesis genes. Collectively, these results elucidated a novel mechanism wherein ABA and ethylene coordinate ripening via FaMADS1-mediated transcriptional repression. This ABA-FaMADS1-ethylene regulatory cascade provides a theoretical basis for targeted postharvest regulation of strawberry ripening, laying a foundation for developing low-cost, hormone-based preservation technologies and molecular breeding strategies to alleviate rapid quality deterioration and economic losses of harvested strawberry. Full article

This study aimed to evaluate the effect of exogenous phosphorus (P) and the abscisic acid (ABA) application on the stomatal physiology of three tomato genotypes: the wild type, ABA-deficient mutant notabilis, and the low ethylene sensitivity mutant Never ripe (Nr). The tomato genotypes were grown in a growth room for 60 days using Hoagland’s nutrient solution. Leaves were then collected, and fragments of the leaf epidermis were sampled and exposed to exogenous solutions of ABA and P for 10 min. The percentage of open and closed stomata, stomatal density, length, and width, and pore area were evaluated, and the maximum stomatal conductance was estimated. ABA promoted stomatal closure in all the genotypes, and the notabilis genotype was less responsive. P promoted stomatal closure in all genotypes, with notabilis being the most responsive and Nr the lowest. P reduced the pore area in all genotypes, with notabilis being the most responsive and Nr the least. P increased the stomatal length but reduced stomatal width in all genotypes. P reduced the stomatal conductance in all genotypes, with notabilis being the most responsive and Nr the least. Excessive P application on the leaf epidermis of tomato promotes stomatal closure and reduction of stomatal conductance, indicating that this closure is directly related to ethylene signaling. Full article

Early detection of contrasting water-stress types is important for understanding plant stress responses and improving water-stress management in forest seedlings. In this study, three-year-old Pinus tabuliformis seedlings were exposed to control (CK, 75–85% of field capacity), drought (D, 25–35% of field capacity), waterlogging (WL, water level flush with the soil surface), and water flooding (WF, water level 2 cm above the soil surface) treatments. Each treatment included 15 independent seedlings at each sampling date, resulting in 420 seedlings across four treatments and seven sampling dates. Needle water potential (Ψw), total chlorophyll content (Chl), maximum photochemical efficiency (Fv/Fm), indole-3-acetic acid (IAA), abscisic acid (ABA), and electrical impedance spectroscopy (EIS) parameters were measured to compare the temporal responses of physiological and electrical traits under different water conditions. EIS showed clear treatment-dependent changes under all stress treatments, with larger changes observed under WF and WL than under D at the treatment levels and durations evaluated in this study. Based on the present discrete sampling schedule, the real (Re) and imaginary (Im) components showed statistical separation among the four treatments in all six pairwise comparisons of the four treatments on Day 7, whereas ABA and Ψw showed separation on Day 11, Fv/Fm on Day 18, and IAA and Chl on Day 25. These results indicate that Re and Im showed treatment-dependent divergence at earlier evaluated sampling dates than the selected physiological variables. Exploratory CLAFIC analysis further indicated group-level spectral separation between CK and WL/WF on Day 3 and between CK and D on Day 7. Overall, EIS-derived features may provide useful information on early electrical responses of P. tabuliformis seedlings to contrasting water conditions. However, further validation using independent datasets, standardized measurement procedures, and field or nursery conditions is required before EIS can be applied as a practical tool for water-stress assessment. Full article

Leaf color in tomato (Solanum lycopersicum L.) is a complex and highly informative trait that reflects pigment metabolism, chloroplast development, genetic regulation, hormonal signaling, and environmental influences. This review synthesizes current knowledge on the biological basis and diversity of tomato leaf coloration, with a particular focus on the roles of chlorophylls, carotenoids, anthocyanins, and flavonoids in generating distinct visual phenotypes. It further discusses the molecular and physiological mechanisms associated with key leaf color types, including dark green, pale green, chlorotic, purple, albino, and variegated leaves, and describes how these phenotypes develop through coordinated regulation of pigment biosynthesis, chloroplast biogenesis, and stress-responsive pathways. The review also summarizes the effects of environmental factors such as light, temperature, water availability, nutrient status, salinity, heavy metals, and biotic stress on leaf pigmentation through changes in photosynthetic efficiency and oxidative balance. In addition, hormonal regulation of leaf color is discussed with emphasis on the roles of abscisic acid (ABA), ethylene (ET), cytokinins (CKs), auxins, jasmonic acids (JA), and salicylic acid (SA) in regulating chlorophyll retention and senescence-associated color transitions. Importantly, leaf coloration functions not only as a morphological trait but also as a sensitive biomarker of plant physiological status, enabling early detection of nutrient deficiencies, abiotic stress, and disease. Recent advances in multi-omics approaches, imaging technologies, and machine learning have significantly improved the understanding of the regulatory networks controlling leaf pigmentation and their relationship with crop performance. However, important gaps remain in integrating molecular mechanisms with whole-plant and field-level responses. Future progress will depend on combining systems biology, high-throughput phenotyping, and predictive modeling to translate leaf color studies into practical applications for improving tomato productivity, stress resilience, and climate adaptation. Full article

In dormant sunflower achenes, several structures—the pericarp, seed coat and embryo—contribute to the repression of germination. Achene dormancy varies widely among cultivated sunflower genotypes, and understanding its transmission to hybrid progeny is important both for hybrid seed production and for clarifying the role of these structures. This study examined the inheritance of dormancy in the F1 progeny, with particular emphasis on thermo-inhibition (inhibition of germination at warm temperatures). Reciprocal crosses were performed using three oilseed inbred lines with contrasting dormancy phenotypes. Germination of achenes, seeds, and embryos was tested at 10 and 30 °C at harvest and during postharvest, together with hormonal responses (abscisic acid, ethylene and gibberellins) and measurements of endogenous ABA levels. Results show that maternally inherited, pericarp-imposed thermo-inhibition depends on the dormancy level of the hybrid embryo, which follows a zygotic pattern with incomplete dominance. While embryo sensitivity to ABA related positively with thermo-inhibition, surprisingly, embryonic ABA content was inversely related to dormancy level across genotypes. These findings provide new insight into physiological control of achene dormancy in sunflower and contribute to improved breeding strategies for high-quality hybrid seed. Full article

Sea Island cotton (Gossypium barbadense L.) is a premium raw material for high-end textiles due to its excellent fiber quality. The AP2/ERF transcription factor family plays critical roles in plant growth and hormone signaling. Here, 161 GbERF family members were identified in Sea Island cotton and classified into nine subgroups, with GbERF13 belonging to Group V. Expression analysis revealed that GbERF13 was specifically and highly expressed in fibers, with transcript abundance peaking at 15–30 days post-anthesis (DPA), coinciding with the transition from fiber elongation to secondary wall thickening. Exogenous abscisic acid (ABA) treatment significantly induced GbERF13 expression and inhibited fiber elongation. Heterologous overexpression of GbERF13 in Arabidopsis increased trichome and root hair numbers while suppressing primary root growth, confirming its role in cell elongation and development. A nonsynonymous SNP (A/C) at the 117th base pair of the GbERF13 coding region (GbERF13-117SNP) was identified in 213 Sea Island cotton accessions. Association analysis showed the C allele was significantly and positively associated with fiber length, strength, and uniformity. An allele-specific PCR marker was further developed for molecular breeding. Collectively, GbERF13 acts as a key ABA-responsive transcription factor regulating fiber development, and its functional SNP marker provides a valuable tool for improving Sea Island cotton fiber quality. Full article

Salt stress severely restricts plant growth and reduces crop yield. Strigolactones (SLs) are carotenoid-derived phytohormones involved in the regulation of plant salt tolerance. Salt stress can modulate the expression of SL biosynthetic and signaling genes, thereby affecting SL accumulation and signaling responses. SLs also interact with abscisic acid (ABA), reactive oxygen species (ROS), and other signaling molecules to coordinate downstream stress responses. At the physiological level, SLs alleviate salt stress by maintaining Na⁺/K⁺ homeostasis, enhancing osmotic adjustment and antioxidant defense, and reducing damage to the photosynthetic system. In addition, SLs can enhance plant resource acquisition and adaptive capacity under salt stress by regulating root architecture and promoting hyphal branching of arbuscular mycorrhizal fungi (AMF). This review focuses on SL-mediated regulation of plant salt tolerance at the molecular and physiological levels and further summarizes exogenous SL application strategies for alleviating salt stress, as well as research progress on key genes in the SL pathway for the genetic improvement of salt tolerance. Clarifying the potential of SLs in regulating plant responses to salt stress could provide new insights into sustainable crop production in saline-alkali environments. Full article

Soil salinity severely limits plant growth by disrupting cellular homeostasis and inducing oxidative damage. Although ethylene-responsive transcription factors (ERFs) are central regulators of stress responses, the function of ERF013 in salt stress responses remains poorly understood. In this study, we investigated the role of ERF013 in Arabidopsis thaliana using ERF013 overexpression lines (OE-ERF013) and genome-edited (ge-erf013) under 250 mM NaCl stress, in comparison with wild-type control (CK) and salt-treated wild-type (WT) plants. Under salinity stress, OE-ERF013 plants maintained vigorous shoot and root growth, exhibiting a 17% increase in shoot fresh weight and a 100% in root fresh weight relative to WT-T plants, whereas ge-erf013 mutants displayed severe growth inhibition. Salt stress markedly elevated superoxide (O₂⁻) and hydrogen peroxide (H₂O₂) levels in WT-T (62% and 134%) and ge-erf013 plants (122% and 193%) compared with CK, while OE-ERF013 plants showed a significant reduction in O₂⁻·and H₂O₂ levels, which decreased by 34% and 64%, respectively, relative to WT-T. Improved redox homeostasis in OE-ERF013 plants was associated with enhanced catalase (CAT) and superoxide dismutase (SOD) activities (55% and 44%), increased DPPH radical-scavenging activity (62%), maintained total antioxidant capacity (ABTS), and reduced lipid peroxidation, whereas ge-erf013 plants exhibited a 47% increase in malondialdehyde (MDA) content relative to WT-T. Furthermore, OE-ERF013 plants displayed reduced electrolyte leakage and sustained higher relative water content (RWC), with only a 15% decline under salt stress. Transcript analysis revealed strong upregulation of key ion homeostasis genes (SOS1, SOS2, NHX1, and HKT1) in OE-ERF013 plants, while their expression was suppressed in ge-erf013 mutants relative to WT-T. Additionally, OE-ERF013 plants accumulated higher abscisic acid (ABA) levels and showed increased expression of ABA biosynthesis-related genes (ATAO3 and ATABA3), accompanied by enhanced osmotic adjustment through elevated proline, soluble sugars, and sucrose accumulation, as well as improved chlorophyll stability. Collectively, these results demonstrate that ERF013 acts as a positive regulator of responses to salinity by coordinating ABA signaling, antioxidant defense, ion homeostasis, and osmotic regulation in Arabidopsis thaliana. Full article

Increasingly frequent and severe drought events restrict global agricultural productivity. As sessile organisms, cereal crops have evolved phenotypic plasticity, drawing on drought escape (DE) and drought avoidance (DA) strategies to balance survival and reproduction. While the mechanisms governing photoperiodic flowering and drought responses are well characterized individually, their molecular intersection remains poorly understood. This review summarizes recent advances in the crosstalk between these two pathways. We highlight the divergent roles of core genetic hubs, such as florigen regulation, GIGANTEA (GI), DELLA proteins, and dual-function transcription factors (e.g., ZmCCT, Ghd7, Ppd-H1), and the breeding-selected alleles, including Green Revolution variants, that can partly uncouple stress tolerance from developmental penalties, though trade-offs often remain. Furthermore, we examine the internal networks driving this crosstalk, including circadian clock phase shifts, sugar and energy signaling through the trehalose-6-phosphate (T6P)-SNF1-related protein kinase 1 (SnRK1) module, and the antagonistic balance within phytohormone networks centered on abscisic acid (ABA). Finally, we propose that integrating epigenetic stress memory, systemic root-to-shoot signaling, and targeted CRISPR/Cas promoter engineering provides a useful conceptual framework for breeding climate-resilient, yield-stable crops. Full article

Brassica napus L. is a major oilseed crop whose productivity is significantly affected by abiotic stresses such as drought. PYR/PYL/RCAR (PYL) proteins act as key abscisic acid (ABA) receptors and play central roles in stress responses. However, a comprehensive genome-wide analysis of the PYL gene family in B. napus is still lacking, limiting our understanding of their functions in plant and stress adaptation. This study reports the first comprehensive genome-wide analysis of the PYL gene family in B. napus (rapeseed), cultivar ZS11, identifying 25 BnPYL genes grouped into four subfamilies, I (four genes), I-II (five genes), II (five genes), III (11 genes), and their encoded proteins were predicted to be mainly localized in the chloroplast. Structural analysis revealed diverse exon–intron organization and 10 conserved motifs. All identified BnPYLs contained Polyketide_cyc2 domains (PF10604), supporting their annotation as members of the PYL family. Promoter analysis identified cis-regulatory elements related to light response, stress regulation, and hormonal signaling. Computational analysis of post-translational modifications suggested that phosphorylation sites are mainly localized at serine and threonine residues. Tertiary structure modelling revealed conserved three-dimensional architectures among BnPYL proteins, suggesting potential functional conservation. Expression profiling and RT-qPCR analyses revealed that several BnPYL genes respond to ABA-mediated drought stress, with BnPYL15 and BnPYL22 exhibiting the highest induction (4–5-fold) and BnPYL2, BnPYL5, BnPYL6, BnPYL17, BnPYL18, and BnPYL25 showing significant upregulation (2.0–4.5-fold), suggesting potential roles in enhancing drought tolerance in B. napus. Full article

N-acetylserotonin methyltransferase (ASMT) is among the key enzymes involved in the final steps of melatonin biosynthesis. Here, we have shown that inactivation of ASMT in A. thaliana results in reduced endogenous melatonin levels, modulating other plant hormone pathways and affecting stress-related responses. Transcriptomic analysis of the asmt-null mutant revealed that the differentially expressed genes were predominantly enriched in terms associated with auxin responses and signalling, as well as with abscisic acid (ABA)-mediated stress responses. In addition, the expression of genes involved in the ethylene, salicylic acid, jasmonic acid and brassinosteroid pathways was altered in the mutant. Assays of a β-glucuronidase (GUS) construct in which a fragment containing 1000 bp upstream of the ASMT start codon was fused to the GUS reporter gene confirmed that ASMT is involved in the responses to ABA, gibberellic and indole acetic acids, trans-zeatin, ethylene and epibrassinolide, which is consistent with the results of the in silico analysis of the ASMT promoter. Furthermore, the expression of a number of genes, such as SLG1, HIS1-3, AtAIRP1 and several LEA genes, whose transcriptional regulation is associated with water management and contributes to impaired tolerance to dehydration stress, was altered in the mutant. The pleiotropic effects of ASMT gene disruption facilitate the identification of new potential melatonin targets and provide insights into the specific mechanisms of melatonin action. Full article

Drought stress is one of the most prevalent abiotic stressors and severely impairs plant growth and productivity. Therefore, identifying functional genes associated with drought tolerance is essential for the molecular breeding of drought-resistant crops. The RD22 (Responsive to Desiccation 22) gene family encodes conserved BURP domain-containing proteins that participate in plant responses to drought stress. In this study, two RD22 homologs, DsRD22a and DsRD22b, were isolated and characterized from the drought-tolerant ornamental species Dianthus spiculifolius. Sequence analysis showed that both proteins contain a conserved BURP domain and are typical members of the RD22 family. Tissue-specific expression analysis revealed that both genes were predominantly expressed in leaves and stems. Abiotic stress assays demonstrated that the expression levels of DsRD22a and DsRD22b were significantly induced by abscisic acid (ABA), osmotic stress, and salt stress, whereas their transcriptional responses to relatively low-temperature and oxidative stress were relatively weak. Subcellular localization analysis indicated that DsRD22a and DsRD22b proteins are localized in the cytoplasm. Heterologous overexpression assays showed that transgenic Arabidopsis thaliana lines overexpressing DsRD22a or DsRD22b exhibited significantly enhanced tolerance to salt and osmotic stresses compared with wild-type (WT) plants. Soil drought assays further confirmed that the transgenic lines had higher soluble protein contents and improved drought tolerance than WT plants. These findings suggest that DsRD22a and DsRD22b positively regulate plant responses to drought stress, potentially by promoting soluble protein accumulation. Collectively, DsRD22a and DsRD22b represent valuable candidate genes for the genetic improvement of drought tolerance in plants. Full article

Selenium is an essential micronutrient for humans, underscoring its importance in enhancing the nutritional and physiological attributes of agricultural and horticultural crops through exogenous application. At low doses, selenium improves growth and development, and increases crop yield and quality, particularly under stress conditions. It is believed that abscisic acid and sucrose work together to regulate strawberry (Fragaria × ananassa Duch.) fruit ripening. This study aimed to provide comprehensive biochemical and molecular insights into the selenium mediated effects on ripening and quality changes in ‘Camarosa’ strawberry fruits. Selenium treatment increased chlorophyll levels in leaves, suggesting a positive impact on overall plant health. Foliar application of 1 mM selenium significantly accelerated ripening. Treated fruits exhibited higher levels of total soluble solids, along with a decrease in titratable acidity. About lipid peroxidation indices, foliar application of 1 mM selenium decreases hydrogen peroxide and malondialdehyde. Consistently, flavonoids, phenolic compounds, anthocyanins, ascorbic acid, and antioxidant capacity, as well as the activity of the enzymes SOD, CAT, APX and PAL, were increased by selenium treatment. Interestingly, the ABA content in strawberry fruits also increased with selenium treatment. The selenium treatment upregulated genes involved in abscisic acid biosynthesis, phenolic compound biosynthesis, and anthocyanin production, namely, FaNCED1, FaG2BD, FaCHS, FaPAL, and FaSUT1. This study highlights the potential of selenium as a biostimulant and quality-enhancing agent in strawberries, improving fruit biochemical composition and ripening dynamics while contributing to better nutritional value and market appeal. Full article

The Sugars Will Eventually be Exported Transporters (SWEET) family plays a crucial role in the carbohydrate distribution, phloem loading, and stress response of plants, yet the evolutionary characteristics and functional diversification of SWEET genes in the endangered timber species Phoebe bournei (Hemsl.) Yen C. Yang remain largely unexplored. In this study, 21 PbSWEET genes were identified and classified into four subfamilies (A–D). Subfamily A exhibited a unique lineage expansion, mainly driven by tandem and segmental duplications. The nonsynonymous-to-synonymous substitution ratio (Ka/Ks) values of all duplicate gene pairs were all less than 1, indicating a strong selective suppression effect; consistent with this evolutionary constraint, the majority of PbSWEET proteins harbor the conserved Medicago truncatula Nodulin 3/saliva (MtN3_slv) domain, with only a few exceptions lacking a complete version. Promoter and hormone response analyses revealed that under abscisic acid (ABA) stress, PbSWEET4 exhibited an immediate burst, whereas PbSWEET10 showed a delayed burst. Physiological data indicated that soluble sugars may be more dominant osmolytes than proline (Pro), a pattern that points to a potential carbon-centric regulatory strategy. PbSWEET4 showed an early burst before sugar/oxidative peaks, suggesting a possible non-canonical signaling role, whereas PbSWEET10 exhibited a late increase coinciding with sugar/malondialdehyde (MDA) peaks, suggesting potential involvement in sugar redistribution. Under methyl jasmonate (MeJA) treatment, PbSWEET10 was rapidly induced, yet sugar accumulation occurred only at 24 h, a temporal decoupling that suggests a possible transcription–metabolism decoupling. Collectively, these correlative patterns point to a possible dual-wave transcriptional mechanism and nominate PbSWEET10 as a candidate for stress response, though these inferences require functional validation. Full article