Search Results (114)

Plants are continuously exposed to multiple environmental stressors throughout their lifecycle. Understanding their integrated physiological, biochemical, and anatomical responses under combined stress conditions is crucial for developing effective approaches to improve stress tolerance and maintain crop productivity. This study aimed to investigate the physiological, biochemical, and anatomical changes in photomorphogenic Micro-Tom plants exposed to high irradiance and water deficit—an abiotic stress combination that commonly co-occurs in natural environments but remains poorly understood in light-sensitive genotypes. We hypothesized that the high pigment 1 (hp1) mutant, due to its enhanced light responsiveness, would display improved stress acclimation compared to the wild-type when exposed to combined stress factors. This study was conducted in a controlled plant growth chamber, using a randomized block design with five replicates. Two Micro-Tom genotypes (wt and hp1) were exposed to control (soil at field capacity (FC) + 450 μmol m⁻² s⁻¹ PPFD) and combined stress (40% FC + 1800 μmol m⁻² s⁻¹ PPFD) conditions. Despite the higher concentration of chloroplast pigments in hp1, its photosynthetic performance under combined stress was not significantly improved, and its defense mechanisms did not effectively mitigate the stress impacts. Anatomically, wt exhibited greater structural adjustment, observed by adaptations in the spongy parenchyma and mesophyll. Overall, the wt genotype showed stronger defense mechanisms, while hp1 was more susceptible to combined abiotic stress. Full article

Bacterial wilt (BW) is a globally serious soil-borne disease in a wide range of plants, caused by diverse strains of Ralstonia solanacearum. However, there are few research reports on melatonin regulating plant resistance against R. solanacearum. N-acetyltransferase SlSNAT2 is a rate-limiting enzyme in plant melatonin synthesis. This study elucidates the mechanisms of SlSNAT2 modulating tomato resistance to BW. SlSNAT2 was expressed in tomato roots, stems, and leaves and induced upon R. solanacearum inoculation. Knocking out SlSNAT2 significantly decreased the melatonin content in CRISPR/Cas9 mutant slsnat2. With R. solanacearum inoculation, the morbidity and disease index value of slsnat2 were significantly higher than those of the tomato wild-type plant Micro-Tom (MT) according to the wilt rate and severity. The chlorophyll levels, photosynthetic rates, and callus deposition quantity in slsnat2 were notably lower while the reactive oxygen species (ROS) level was considerably higher than those in the MT after inoculation. Additionally, the SlSNAT2 deficiency depressed the expression of the mitogen-activated protein kinase (MAPK) pathway genes (SlMPK1, SlMKK2), salicylic acid pathway genes (SlGluA, SlPR-1a), jasmonic acid pathway gene SlPin2, and pathogenesis-related (PR) protein genes (SlPR-STH2a, SlPR-STH2b, SlPR-STH2c, SlPR-STH2d). These results revealed SlSNAT2 enhanced the tomato resistance against R. solanacearum by orchestrating ROS homeostasis, callose deposition, MAPK signaling, hormone pathways, and PR gene transcripts. Full article

The tomato (Solanum lycopersicum L.) is one of the most consumed crops worldwide and a source of antioxidants. Given the role the latter play against oxidative stress and free radical-related diseases, enhancing tomato bioactive compound production would be appealing for a wide range of applications in the fields of nutrition, pharmacy, and biotechnology. This study explores a sustainable and innovative approach: the modulation of specific light spectra to boost the production of bioactive compounds in tomatoes (cultivar ‘Microtom’). We investigated how three light regimes—white fluorescent (FL), full-spectrum (FS), and red-blue (RB)—influence the accumulation of polyphenols and other key nutraceuticals during plant growth. Our findings reveal that full-spectrum (FS) light significantly enhances the levels of polyphenols, flavonoids, tannins, ascorbic acid, and lycopene in tomato fruits, compared to those grown under RB or FL light. Interestingly, fruits from RB light-grown plants showed the highest carotenoid concentrations and antioxidant capacity. These results suggest that light quality actively modulates the expression of key enzymes in the phenylpropanoid and flavonoid biosynthetic pathways, shaping each fruit’s unique metabolic fingerprint. Cluster analysis confirmed that RB, FL, and FS conditions lead to distinct polyphenolic profiles, each with notable health-promoting potential. Our results highlight a promising avenue: tailoring light environments to enhance the functional value of crops, bridging agriculture, nutrition, and biomedicine in a sustainable way. Full article

Salt stress is a major constraint to crop productivity, negatively affecting plant physiology and fruit quality. This study hypothesized that seed priming with polyethylene glycol (PEG6000) might enhance antioxidant activity by mitigating oxidative stress in Solanum lycopersicum ‘Micro-Tom’ under salt stress. Seeds primed with –1.2 MPa PEG6000 were grown in Rockwool and treated with 0, 50, 100, 150, and 200 mM NaCl. Primed plants showed a 32% increase in leaf potassium (K⁺) and a 28% decrease in sodium (Na⁺) accumulation compared to non-primed plants under 150 mM NaCl. Glucose, fructose, and sucrose contents increased by 25%, 22%, and 19%, respectively, in primed fruits, while citric acid decreased by 15%. Malondialdehyde (MDA) and electrolyte leakage were reduced by 35% and 29%, respectively, in primed plants under moderate salinity. Antioxidant enzyme activities—SOD, POD, CAT, and APX were enhanced by 30–45% in primed plants under 100 and 150 mM NaCl, compared to non-primed controls. Abscisic acid (ABA) levels increased by 40% in primed roots under salt stress. Activities of polyamine-related enzymes (DAO, PAO, and ADC) also rose significantly. Priming improved protein content by 20% and relative water content by 18%. These results suggest that PEG6000 seed priming enhances salt tolerance by boosting antioxidant defense, regulating osmotic balance, and improving ion homeostasis, offering a viable strategy for sustaining tomato productivity under salinity. Full article

The study of woody dicot xylem structure in relation to habitats has a long but geographically incomplete history, generating generalizations and questions still in need of expanded data. One understudied area is localized cross-habitat studies under identical climate conditions. Also sparse are intraspecific cross-habitat data. Both of these weaknesses are addressed in the present project for unstudied S. Florida. Six surveys of woody dicot branchlet microtome cross-sections allowed the microscopic comparison of vessel element (VE) diameters and VE densities. The project took place in a small area within short timeframes per survey to assure near uniformity in weather and in seasonal growth cycles. The multispecies Initial Survey and single-species Ximenia americana Survey addressed the question of adjustments in VE diameters and/or VE densities in shaded vs. sunny habitats, finding significant downward average adjustment in VE densities in shaded hammock vs. open pineland habitats (112 shade vs. 182 VE/mm² sun) but not in VE diameters. Single-species (Chrysobalanus icaco, Morella cerifera) surveys examined adjustments in VE diameters and VE densities in swamp vs. scrub (diameter mean: 42.5 µm swamp, 49.2 µm scrub; density means: 179.9 swamp, 154.0 scrub). Chrysobalanus icaco, having arguably the greatest environmental breadth and having the largest mean vessel element diameters in the project, was the sole species to adjust VE diameters only across habitats. Coefficients of variation in VE density exceeded those in VE diameters in every survey. This project sets the stage for future work in Florida and beyond aimed at isolation of environmental variables with respect to xylem traits and aimed at causal mechanisms, especially mode of xylem adjustment in relation to conductive risk. Full article

Background: Tomatoes are self-pollinating plants, and successful fruit set depends on the production of functional pollen within the same flower. Our previous studies have shown that the ‘Black Vernissage’ tomato variety exhibits greater resilience to heat stress in terms of pollen productivity compared to the ‘Micro-Tom’ variety. Pollen productivity is determined by meiotic activity during microsporogenesis and the development of free microspores during gametogenesis. This study focused on identifying heat stress (HS)-induced proteomes in pollen mother cells (PMCs) and microspores. Methods: Tomato plants were grown under two temperature conditions: 26 °C (non-heat-treated control) and 37 °C (heat-treated). Homogeneous cell samples of meiotic PMCs (prior to the tetrad stage) and free microspores were collected using laser capture microdissection (LCM). The heat-induced proteomes were identified using tandem mass tag (TMT)–quantitative proteomics analysis. Results: The enrichment of the meiotic cell cycle in PMCs and the pre-mitotic process in free microspores confirmed the correlation between proteome expression and developmental stage. Under HS, PMCs in both tomato varieties were enriched with heat shock proteins (HSPs). However, the ‘Black Vernissage’ variety exhibited a greater diversity of HSP species and a higher level of enrichment compared to the ‘Micro-Tom’ variety. Additionally, several proteins involved in gene expression and protein translation were downregulated in PMCs and microspores of both varieties. In the PMC proteomes, the relative abundance of proteins showed no significant differences between the two varieties under normal conditions, with very few exceptions. However, HS induced significant differential expression both within and between the varieties. More importantly, these heat-induced differentially abundant proteins (DAPs) in PMCs are directly involved in meiotic cell division, including the meiosis-specific protein ASY3 (Solyc01g079080), the cell division protein kinase 2 (Solyc11g070140), COP9 signalosome complex subunit 1 (Solyc01g091650), the kinetochore protein ndc80 (Solyc01g104570), MORC family CW-type zinc finger 3 (Solyc02g084700), and several HSPs that function in protecting the fidelity of the meiotic processes, including the DNAJ chaperone (Solyc04g009770, Solyc05g055160), chaperone protein htpG (Solyc04g081570), and class I and class II HSPs. In the microspores, most of the HS-induced DAPs were consistently observed across both varieties, with only a few proteins showing significant differences between them under heat stress. These HS-induced DAPs include proteases, antioxidant proteins, and proteins related to cell wall remodeling and the generation of pollen exine. Conclusions: HS induced more dynamic proteomic changes in meiotic PMCs compared to microspores, and the inter-varietal differences in the PMC proteomes align with the effects of HS on pollen productivity observed in the two varieties. This research highlights the importance of the cell-type-specific proteomics approach in identifying the molecular mechanisms that are critical for the pollen developmental process under elevated temperature conditions. Full article

Research exploring involvement of RNA N⁶-methyladenosine (m⁶A) in tomato (Solanum lycopersicum) seed germination remains limited. There is also a lack of direct evidence supporting the interaction among tomato seed germination, microgravity, and m⁶A modification. In this study, Micro-Tom tomatoes are used as the experimental material to conduct tomato genetic transformation, seed germination assay, and m⁶A modification levels identification experiments. During tomato seed germination processes, the m⁶A modification level significantly increases under the mutual influence of various m⁶A methyltransferase subunits and multiple eraser proteins. As a m⁶A reader gene, SlYTP9 expression significantly affects the germination of tomato seeds, with promotion and inhibition in OE (overexpression) and RNAi (RNA interference) transgenic tomato plants, respectively. Microgravity promotes seed germination in the early germination period (0–3 days past germination; 0–3 DPG), but this promoting effect gradually disappears as the seedling grows (8–15 DPG). Further exploration revealed that this promoting effect is correlated with m⁶A modification, manifested as enhanced expression of most m⁶A writer genes; increased expression levels of overall reader genes; altered expression trends of some m⁶A eraser genes, particularly SlALKBH2; and enhanced m⁶A modification levels. The experimental results obtained in this study can provide a theoretical basis and evidence support for elucidating the role of m⁶A in tomato seed germination, as well as for exploring the interactions between seed germination, microgravity, and m⁶A modification. Full article

Solanum lycopersicum, a widely cultivated vegetable crop globally, faces soil cadmium (Cd) contamination issues due to Cd’s high mobility, posing potential threats to Solanum lycopersicum growth and human health. In light of this, this study selected three representative Solanum lycopersicum varieties: Micro Tom, Red Guanyin, and Taiwan Pink King, and designed a series of experiments to investigate their growth performance under Cd stress. Experimental treatments included the sole application of different concentrations of Vitekang soil conditioner (VT), as well as the individual and combined application of VT and arbuscular mycorrhizal fungi (AMF). By thoroughly analyzing agronomic traits, cellular membrane lipid peroxidation levels, the activities of antioxidant enzymes (Catalase (CAT), Superoxide Dismutase (SOD), and Peroxidase (POD)), and the expression levels of genes related to Cd transport and detoxification (SLNRAMP6 and SlHMA3), this study comprehensively evaluated the effectiveness of different treatments in mitigating Cd stress in the three Solanum lycopersicum varieties. The results indicated that when VT was applied at a concentration of 2.4 g/kg in combination with AMF, it significantly reduced the detrimental effects of Cd on Micro Tom, Red Guanyin, and Taiwan Pink King. The specific experimental outcomes were as follows: (i) significantly decreased Cd accumulation in Solanum lycopersicum roots and leaves; (ii) effectively mitigated cellular membrane lipid peroxidation; (iii) significantly increased antioxidant enzyme activities; and (iv) influenced expression patterns of genes related to Cd transport and detoxification. This study further confirms that, compared to the sole application of VT or AMF, the combined application of these two treatments serves as a more effective practical method, exhibiting significant advantages in alleviating soil Cd contamination, promoting Solanum lycopersicum growth, and improving agronomic traits. This study not only advances research progress on VT and AMF in Solanum lycopersicumes, providing a solid theoretical and experimental foundation for cultivating high-quality Solanum lycopersicumes, but also holds significant importance for improving and optimizing the “VIP+N” technology, achieving farmland soil protection, and enhancing agricultural product quality. Full article

Background: Phospholipase A (PLA) enzymes catalyze the hydrolysis of glycerophospholipids, releasing free fatty acids and lysophospholipids that play vital roles in plant growth, development, and stress responses. Methods: This study identified and analyzed SlPLA genes through bioinformatics and further explored the function of PLA genes under cold stress through virus-induced gene silencing (VIGS) experiments. Results: This study systematically characterized the SlPLA gene family in tomato, identifying 80 genes distributed across 12 chromosomes. Phylogenetic analysis categorized these genes into three groups: pPLA, PLA1, and PLA2. Conserved motifs and gene structure analysis revealed distinct patterns, with some genes lacking untranslated regions (UTRs), which suggests functional diversification. Promoter analysis indicated that SlPLA genes are regulated by light, hormones, and stress-related elements, particularly cold stress. RNA-seq data and qRT-PCR results indicated the differential expression of SlPLA genes across various tissues in tomato cultivars (Heinz and Micro-Tom). Under cold stress, certain SlPLA genes, especially SlPLA1-2, were up-regulated, suggesting their involvement in cold tolerance. Silencing SlPLA1-2 resulted in increased membrane damage, elevated malondialdehyde (MDA) levels, higher electrolyte leakage, and a lower expression of cold-responsive genes within the ICE1-CBF-COR pathway and jasmonic acid (JA) biosynthesis. Conclusions: This study discovered 80 SlPLA genes in tomato across 12 chromosomes, categorizing them into pPLA, PLA1, and PLA2 via phylogenetic analysis. The qRT-PCR analysis identified that SlPLA1-2 was strongly induced by cold stress, and further experiments regarding genetics and physiology revealed that SlPLA1-2 boosts the cold tolerance of tomato by affecting the CBF signaling pathway and JA biosynthesis, offering insights for future stress-resilience breeding. Full article

The study investigates selected parameters describing the fibers of black locust (Robinia pseudoacacia L.) wood with regard to tree age and size (diameter). The material was collected in stands aged 38, 60, and 71 years growing on the mesotrophic sites in southwestern Poland. In each stand, we sampled trees from three diameter classes (thin, medium, and thick specimens). From each tree, we took two 20 mm × 20 mm × 30 mm wood samples, from which we cut slices from the tangential plane using a sliding microtome. The Olympus cellSens Standard software was used to take pictures of 15 fibers per sample. In total, studies were carried out on 510 fibers. We measured fibers’ dimensional parameters (length, diameter, lumen, and wall thickness) with ImageJ 1.8.0 software and, based on these, we calculated the fiber shape coefficients (slenderness ratio, rigidity index, Runkel ratio, flexibility coefficient, Mühlsteph index, and solids index). Both the age and size of trees significantly influenced the examined parameters of black locust fibers, with the single exception of fiber lumen, which was dependent only on tree age. In general, the examined age classes differed one from another, while, in the case of tree size, significantly different values were usually only found for the thinnest trees. Our results suggest that wood of medium-thick, medium-sized, or older black locust trees seems to be the most appropriate raw material for paper or pulp production, as it has the least variability in the analyzed features. The wood of the youngest trees would be potentially the least useful for these applications. Full article

Electron microscopy (EM) is a key tool for studying the microstructure of wood; however, observing uncoated samples poses a challenge due to surface charging. This study aims to identify the critical voltage that allows for the effective observation of uncoated wood samples without significant loading. As part of the experiment, samples of different wood species were tested, including Acacia (Robinia pseudoacacia L.), Oak (Quercus robur L.), Maple (Acer pseudoplatanus spp.), Ash (Fraxinus excelsior L.), Spruce (Picea abies (L.) Karst.), Thermowood (Thermal modifed Spruce), Garapa (Apuleia leiocarpa), Ipé (Handroanthus spp.), Merbau (Intsia bijuga), and Massaranduba (Manilkara spp.). Several methods were tested for surface preparation for SEM analysis, including the use of a circular saw, a hand milling machine, and a microtome. The results show that the optimal voltage for observing uncoated wood samples varied depending on the wood species. Regarding the selection of wood species and the results obtained, it was found that uncoated samples could be effectively observed. This finding suggests that practical observations can be accelerated and more cost-effective, as all wood species exhibited the required voltage range of 1 kV to 1.6 kV. Additionally, it was determined that using a secondary electron detector was optimal for such observations, as it provided a sufficiently strong signal even at relatively low voltages. Conversely, when using a backscattered electron detector, it was more beneficial to use coated samples to achieve a sufficient signal at higher voltages. This study brings new knowledge that will facilitate further research and applications of electron microscopy in the study of other wood species or wood-based materials. Full article

Tomato is a widely grown horticultural crop, and its growth process is often affected by high temperatures. Caseinolytic Protease B (ClpB), a homologous protein to heat shock protein 101 (HSP101), plays a vital role in plant heat adaptation and development. In this study, we identified six SlClpB genes in tomatoes, distributed across four chromosomes. Collinearity analysis revealed that the gene pairs SlClpB-2 and SlClpB-3A, as well as SlClpB-3C and SlClpB-12, resulted from segmental duplication events. Phylogenetic and motif analyses showed that ClpB proteins possess highly conserved domains across different species. We used RNA-seq data to analyze the expression patterns of the ClpB family. Among them, SlClpB-3A and SlClpB-12 exhibited increased expression in multiple tissues under heat stress. Specifically, SlClpB-2, SlClpB-3A, and SlClpB-3C were highly expressed in the fruit orange stage and in flower buds under heat treatment, while in seedlings, SlClpB-2 and SlClpB-3A exhibited heat-induced expression. Real-time quantitative fluorescent PCR (qRT-PCR) results showed that the expression of SlClpB-2 and SlClpB-3A was significantly increased under heat stress in the leaves and buds of Ailsa Craig, Micro-Tom, and M82. Overall, our findings provide valuable insights into the regulatory mechanisms of SlClpB genes in response to heat stress. Full article

In arid areas, water shortage has become a major bottleneck limiting the sustainable development of agriculture, necessitating improved water use efficiency and the full development of innovative water-saving irrigation management technologies to improve quality. In the present study, tomato (Solanum lycopersicum cv. Micro Tom) fruits were used as materials, and different irrigation frequencies were set during the fruit expansion stage. The normal treatment (CK) was irrigated every three days, while the water deficit treatments were irrigated at varying frequencies: once every 4 days (T1), 5 days (T2), 6 days (T3), 7 days (T4), and 8 days (T5). These corresponded to 80%, 70%, 60%, 50%, and 40% of the maximum field moisture capacity (FMC), respectively, with CK maintaining full irrigation at 90% of the maximum FMC. The water deficit treatment T3, with less stress damage to plants and the most significant effect on fruit quality improvement, was selected based on plant growth indices, photosynthetic characteristics, chlorophyll fluorescence parameters, and fruit quality indices, and its effects on carotenoids, glycolic acid fractions, and volatile compounds during tomato fruit ripening were further investigated. The outcome indicated that moderate water deficit significantly increased the carotenoid components of the tomato fruits, and their lycopene, lutein, α-carotene, and β-carotene contents increased by 11.85%, 12.28%, 20.87%, and 63.89%, respectively, compared with the control fruits at the ripening stage. The contents of glucose and fructose increased with the development and ripening of the tomato fruits, and reached their maximum at the ripening stage. Compared to the control treatment, the moderate water deficit treatment significantly increased the glucose and fructose levels during ripening by 86.70% and 19.83%, respectively. Compared to the control conditions, water deficit conditions reduced the sucrose content in the tomato fruits by 27.14%, 18.03%, and 18.42% at the mature green, turning, and ripening stages, respectively. The moderate water deficit treatment significantly increased the contents of tartaric acid, malic acid, shikimic acid, alpha ketoglutaric acid, succinic acid, and ascorbic acid, and decreased the contents of oxalic acid and citric acid compared to the control. The contents of total soluble sugar and total organic acid and the sugar–acid ratio were significantly increased by 48.69%, 3.71%, and 43.09%, respectively, compared with the control at the ripening stage. The moderate water deficit treatment increased the fruit response values to each sensor of the electronic nose, especially W5S, which was increased by 28.40% compared to the control at the ripening stage. In conclusion, during the ripening process of tomato fruit, its nutritional quality and flavor quality contents can be significantly improved under moderate (MD) deficit irrigation treatment. The results of this experiment can lay the foundation for the research on the mechanism of water deficit aiming to promote the quality of tomato fruit, and, at the same time, provide a theoretical basis and reference for tomato water conservation and high-quality cultivation. Full article

Improving edible biomass space use efficacy (EBSUE) is important for sustainably producing edamame and dwarf tomatoes in plant factories with artificial light. Photosynthetic photon flux density (PPFD) may increase EBSUE and space use efficacy (SUE). However, no study has quantitatively explained how PPFD affects EBSUE in edamame and dwarf tomatoes. This study aimed to quantitatively validate the effects of PPFD on EBSUE in dwarf tomatoes and edamame and verify whether this effect differs between these crops. The edamame and dwarf tomato cultivars ‘Enrei’ and ‘Micro-Tom’, respectively, were cultivated under treatments with PPFDs of 300, 500, and 700 µmol m⁻² s⁻¹. The results showed that the EBSUE and SUE increased with increasing PPFD in both crops. The EBSUE increased depending on the increase in SUE, the dry mass ratio of the edible part to the total plant in the edamame, and the SUE only in the dwarf tomatoes. In conclusion, a high PPFD can improve the EBSUE and SUE of edamame and dwarf tomatoes in different ways at the reproductive growth stage. The findings from this study offer valuable information on optimizing space and resource usage in plant factories with artificial light and vertical farms. Additionally, they shed light on the quantitative impact of PPFD on both EBSUE and SUE. Full article

Background and Objectives: Radiofrequency catheter ablation (RFCA) is a highly successful intervention. By comparing the lesion changes in prostate parenchymal and striated muscle tissues after RFCA with and without cooling, it was possible to assess the correlation between the shape regularity, area, and perimeter of the thermal lesion, and to predict the geometric shape changes of the lesions. Materials and Methods: A standard prostate and striated muscle RFCA procedure was performed on 13 non-purebred dogs in two sessions: no cooling and cooling with 0.1% NaCl solution. Microtome-cut 2–3 µm sections of tissue samples were stained with haematoxylin and eosin and further examined. The quotient formula was employed to evaluate the geometric shape of the damage zones at the ablation site. Results: The extent of injury following RFCA in striated muscle tissue was comparable to that in prostate parenchymal tissue. Regression analysis indicated a strong and positive relationship between area and perimeter in all experimental groups. In the experimental groups of parenchymal tissues with and without cooling, an increase in the area or perimeter of the damage zone corresponded to an increase in the quotient value. A similar tendency was observed in the striated muscle group with cooling. However, in the striated muscle group without cooling, an increase in lesion area or perimeter lowered the quotient value. Standardised regression coefficients demonstrated that in the striated muscle with cooling, the damage zone shape was more determined by area than perimeter. However, in the parenchymal tissue, the perimeter had a more substantial impact on the damage zone shape than the area. Conclusions: The damage area and perimeter have predictive power on the overall shape regularity of damage zone geometry in both striated muscles and parenchymal tissue. This approach is employed to achieve a balance between the need for tumour eradication and the minimisation of ablation-induced complications to healthy tissue. Full article