Cold-regulated gene LeCOR413PM2 confers cold stress tolerance in tomato plants.

Tomato (Lycopersicon esculentum Mill) is an important food plant that has been used as a model plant in genetic evolution and molecular biology research. The plant is originated from the tropics; thus, it is sensitive to cold. Its growth and development can be easily affected by cold stress. In this study, cold-regulated gene LeCOR413PM2 was cloned from tomato leaves and then used to generate two types of transgenic tomato plants: LeCOR413PM2-overexpressing transgenic plants and RNA-interference-expressing transgenic plants. The functions and expression of LeCOR413PM2 gene in response to cold stress were subsequently assessed. The results showed that LeCOR413PM2 localized in the plasma membrane. Expression of LeCOR413PM2 gene in the leaf of transgenic tomato plant was highest compared to that in other organs (i.e., root, stem, flower and fruit); it was elevated when plants were treated with cold stress. Overexpression of LeCOR413PM2 gene was found to not only reduce damage to cell membrane, accumulation of ROS, and photoinhibition of PSII, but also maintain high activity of antioxidant enzymes and content of osmotic regulators. The results also reveal that high activities of antioxidant enzymes were caused by the up-regulation of their gene expressions. This study demonstrates that the overexpression of LeCOR413PM2 could increase cold tolerance of transgenic tomato plants, while the suppressed expression of LeCOR413PM2 by RNA interference could increase the sensitivity of plants to cold.

Improved Solid-Phase Extraction for Simple, Sensitive, and Efficient Determination of Trace Plant Growth Regulators in Cherry Tomatoes by High-Performance Liquid Chromatography.

The overuse of plant growth regulators (PGRs) in agricultural products has gradually increased in recent years, resulting in hazardous effects on food safety and human health. For the first time, a sensitive, accurate, and low-cost analytical method involving improved solid-phase extraction coupled with high-performance liquid chromatography was developed to determine trace PGRs in cherry tomatoes. Thereafter, the extraction mechanism and conditions were elucidated. Under optimized conditions, good linearity (0.04-400 ng g-1; r ≥ 0.9996) and lower limits of detection (0.005-0.006 ng g-1) were observed. The recoveries were 81.4-90.1%, with relative standard deviations of ≤6.7% (three levels). Finally, the developed method was successfully used to detect trace PGRs in cherry tomatoes. The results illustrated that this sensitive method shows great potential for application to monitor trace PGRs in agricultural products and, thus, provide technical support for food safety and public health.

Evaluation of allyl isothiocyanate as a soil fumigant against soil-borne diseases in commercial tomato (Lycopersicon esculentum Mill.) production in China.

BACKGROUND: Root-knot nematodes (Meloidogyne spp.), soil-borne diseases and weeds seriously reduce the commercial yield of tomatoes grown under protected cultivation in China. Allyl isothiocyanate (AITC), a natural product obtained from damaged Brassica tissues, was evaluated as a potential replacement for the fumigant methyl bromide (MB) for use in the greenhouse production of tomatoes in China. RESULTS: The dose-response assay indicates that AITC has high biological activity against major bacterial and fungal pathogens (EC50 of 0.225-4.199 mg L-1 ). The bioassay results indicate that AITC has good efficacy against root-knot nematodes (LC50 of 18.046 mg kg-1 ), and moderate efficacy against fungal pathogens (LC50 of 27.999-29.497 mg kg-1 ) and weeds (LC50 of 17.300-47.660 mg kg-1 ). The potting test indicates that AITC significantly improved plant vigor. Field trials indicate that AITC showed good efficacy against Meloidogyne spp. and Fusarium spp. (both ∼ 80%) as well as Phytophthora spp. and Pythium spp. (both ∼ 70%), and improved plant vigor and marketable yield. CONCLUSION: AITC used as a soil fumigant (30-50 g m-2 ) effectively controlled major bacterial and fungal pathogens, root-knot nematode, weeds and increased plant vigor, yield and farmers' income in tomato cultivated under protected agriculture in China. © 2018 Society of Chemical Industry.

Bactericidal effect of silver nanoparticles against propagation of Clavibacter michiganensis infection in Lycopersicon esculentum Mill.

This study explored the use of silver nanoparticle as a bactericidal against the propagation of Clavibacter michiganensis onto tomatoes (Lycopersicon esculentum Mill). In Mexico, tomato production covers about 73% of the total vegetable production but it is affected by outbreak of bacteria canker caused by Clavibacter michiganensis subspecies michiganensis (Cmm). Silver ions possess inhibitor properties, bactericides and high specter antimicrobials. In this study, 6 groups of culture were prepared using 6 different petri dishes where silver nanoparticles of varying concentrations (120, 84, 48, 24, 12 and 0 µg) were added. Furthermore, each group was observed for 20 min, 1, 2, 12 and 24 h. The optimum concentration is 84 µg, which shows an average of 2 Cmm colonies after 20 min. Further increase to 120 µg shows no significant change. However, the average colonies was observed for 48 µg after 1, 2, 12, and 24 h. The obtained results indicate that silver nanoparticles are a promising inhibitor, bactericide and high a specter antimicrobial for treatment or prevention of Cmm.

Modelling the water-plant cuticular polymer matrix membrane partitioning of diverse chemicals in multiple plant species using the support vector machine-based QSAR approach.

In this study, a support vector machine (SVM) based multi-species QSAR (quantitative structure-activity relationship) model was developed for predicting the water-plant cuticular polymer matrix membrane (MX) partition coefficient, KMXw of diverse chemicals using two simple molecular descriptors derived from the chemical structures and following the OECD guidelines. Accordingly, the Lycopersicon esculentum Mill. data were used to construct the QSAR model that was externally validated using three other plant species data. The diversity in chemical structures and end-points were verified using the Tanimoto similarity index and Kruskal-Wallis statistics. The predictive power of the developed QSAR model was tested through rigorous validation, deriving a wide series of statistical checks. The MLOGP was the most influential descriptor identified by the model. The model yielded a correlation (r2) of 0.966 and 0.965 in the training and test data arrays. The developed QSAR model also performed well in another three plant species (r2 > 0.955). The results suggest the appropriateness of the developed model to reliably predict the plant chemical interactions in multiple plant species and it can be a useful tool in screening the new chemical for environmental risk assessment.

Pesticide residue removal in classic domestic processing of tomato and its effects on product quality.

This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters.

Effectiveness of Iron Ethylenediamine-N,N'-bis(hydroxyphenylacetic) Acid (o,o-EDDHA/Fe3+) Formulations with Different Ratios of Meso and d,l-Racemic Isomers as Iron Fertilizers.

Two o,o-EDDHA/Fe3+ formulations (meso, 93.5% w/w of meso isomer; and d,l-racemic, 91.3% w/w of d,l-racemic mixture) were prepared, and their efficacy to avoid or to relieve iron deficiency in Fe-sufficient and Fe-deficient tomato plants grown on hydroponic solution was compared with that of the current o,o-EDDHA/Fe3+ formulations (50% of meso and d,l-racemic isomers). The effectiveness of the three o,o-EDDHA/Fe3+ formulations was different depending on the iron nutritional status of plants. The three o,o-EDDHA/Fe3+ formulations tested were effective in preventing iron chlorosis in healthy plants. However, the higher the meso concentration in the formulations, the higher the effectiveness in the recovery of iron chlorotic plants from iron deficiency. Accordingly, o,o-EDDHA/Fe3+ formulations rich in meso isomer are recommended in hydroponic systems.

Allergenic Potential of Tomatoes Cultivated in Organic and Conventional Systems.

Tomatoes (Lycopersicon esculentum Mill.) are a widely consumed vegetables and contain many health beneficial micronutrients. Unfortunately, they may also cause adverse allergic reactions in sensitized people. Many studies, conducted in recent years, indicate that organically produced vegetables have higher nutritional value, improved sensory quality and contain more health-enhancing bioactive compounds than vegetables grown under the conventional system. However, the relation between organic methods of cultivation and allergenic potential of tomatoes has received little scientific attention. This study analyzed samples of five tomato cultivars taken from organic and conventional systems over three consecutive years. The content of profilin, Bet v 1 and lipid transfer protein (LTP) analogues in tomato samples was determined using an indirect ELISA assay. Substantial quantities of these proteins were found in certain cultivars across all three years of cultivation. On the basis of these findings, organically grown tomatoes appear to offer little advantage over conventionally cultivated plants in terms of reduced allergenic potential.

Efficacy of a coating composed of chitosan from Mucor circinelloides and carvacrol to control Aspergillus flavus and the quality of cherry tomato fruits.

Cherry tomato (Lycopersicon esculentum Mill) fruits are susceptible to contamination by Aspergillus flavus, which may cause the development of fruit rot and significant postharvest losses. Currently there are significant drawbacks for the use of synthetic fungicides to control pathogenic fungi in tomato fruits, and it has increased the interest in exploring new alternatives to control the occurrence of fungal infections in these fruits. This study evaluated the efficacy of chitosan (CHI) from Mucor circinelloides in combination with carvacrol (CAR) in inhibiting A. flavus in laboratory media and as a coating on cherry tomato fruits (25°C, 12 days and 12°C, 24 days). During a period of storage, the effect of coatings composed of CHI and CAR on autochthonous microflora, as well as on some quality characteristics of the fruits such as weight loss, color, firmness, soluble solids, and titratable acidity was evaluated. CHI and CAR displayed MIC valuesof 7.5 mg/mL and 10 µL/mL, respectively, against A. flavus. The combined application of CHI (7.5 or 3.75 mg/mL) and CAR (5 or 2.5 µL/mL) strongly inhibited the mycelial growth and spore germination of A. flavus. The coating composed of CHI (3.75 mg/mL) and CAR (2.5 or 1.25 µL/mL) inhibited the growth of A. flavus in artificially contaminated fruits, as well as the native fungal microflora of the fruits stored at room or low temperature. The application of the tested coatings preserved the quality of cherry tomato fruits as measured by some physicochemical attributes. From this, composite coatings containing CHI and CAR offer a promising alternative to control postharvest infection caused by A. flavus or native fungal microflora in fresh cherry tomato fruits without negatively affecting their quality over storage.

From producer to consumer: greenhouse tomato quality as affected by variety, maturity stage at harvest, transport conditions, and supermarket storage.

Possible causes for differences in quality traits at the time of buying were studied in two widely different red tomato types. Three maturity stages were harvested from commercial greenhouses and transferred immediately to controlled environments simulating different storage, transport, and supermarket conditions. Results show significant differences in development of color, fruit firmness, contents of soluble solids (SSC), titratable acids (TTA), phenolics, and carotenoids from harvest to sale, as related to postharvest conditions. Fruit firmness, SSC, and TTA of vine-ripened red cherry tomatoes was 30, 55 and 11% higher than for those harvested at breakers and ripened to red. Temperature, light, UVC radiation, or ethylene during 4 days transport affected tomato quality traits, and differences persisted during 3 weeks of supermarket storage. Ethylene exposure gave a 3.7-fold increase in lycopene content in cherry tomatoes, whereas UVC hormesis revealed a 6-fold increase compared with the control. Results can be used to update recommendations concerning optimal handling.

Enzyme-aided extraction of lycopene from high-pigment tomato cultivars by supercritical carbon dioxide.

This work reports a novel enzyme-assisted process for lycopene concentration into a freeze-dried tomato matrix and describes the results of laboratory scale lycopene supercritical CO2 (SC-CO2) extractions carried out with untreated (control) and enzyme-digested matrices. The combined use of food-grade commercial plant cell-wall glycosidases (Celluclast/Novozyme plus Viscozyme) allows to increase lycopene (∼153%) and lipid (∼137%) concentration in the matrix and rises substrate load onto the extraction vessel (∼46%) compared to the control. The addition of an oleaginous co-matrix (hazelnut seeds) to the tomato matrix (1:1 by weight) increases CO2 diffusion through the highly dense enzyme-treated matrix bed and provides lipids that are co-extracted increasing lycopene yield. Under the same operative conditions (50 MPa, 86 °C, 4 mL min(-1) SC-CO2 flow) extraction yield from control and Celluclast/Novozyme+Viscozyme-treated tomato matrix/co-matrix mixtures was similar, exceeding 75% after 4.5h of extraction. However, the total extracted lycopene was ∼3 times higher in enzyme-treated matrix than control.

Absolute quantification of protein NP24 in tomato fruit by liquid chromatography/tandem mass spectrometry using stable isotope-labelled tryptic peptide standard.

Protein NP24 is a thaumatin-like protein contained in tomato (Lycopersicon esculentum Mill.). This protein is reported to be a putative tomato allergen and is listed as a food allergen in Structural Database of Allergenic Proteins (SDAP). In this research, we developed the quantitative analysis of NP24 by employing the protein absolute quantification (AQUA) technology composed of stable isotope-labelled internal standard (SIIS) peptide (GQTWVINAPR[(13)C6,(15)N4]) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). A linear relationship (r(2)>0.99) was found throughout the concentration range (2.0-500 fmol/µL). The coefficients of variation (CVs) measured on each of the five days when NP24 contained in the tomato skin was analysed did not exceed 13%. Our developed assay of NP24 will contribute to the allergological examination of tomato and its derived products.

Effect of grafting and ripening conditions on some qualitative traits of 'Cuore di bue' tomato fruits.

BACKGROUND: Grafting technique is increasingly being employed in order to obtain high production in difficult soils and to reduce chemical application. The present experimental work addressed the effect of grafting of tomato, cv. "Profitto" (P), on to the rootstocks "Beaufort" (B) and "Big Power" (BP) on fruit quality. Both fruit left to ripen on the plant and fruit stored at low temperature (4 °C) were included in the quality assessment. RESULTS: Vitamin C and fructose content decreased in B and BP in fruits stored at 4 °C, whereas fruits ripened on the plant showed higher sugar concentrations. The free phenolic acids extracted were identified as caffeic acid, p-coumaric acid, chlorogenic acid and ferulic acid. Higher antioxidant compound content was consistently shown by P. Cold storage conditions caused a higher phenolic acid production due to the increase of ferulic acid. Compared with ripening on the plant, percentage differences ranged between 14.3% (caffeic acid) and 12.5% (p-coumaric and chlorogenic acids). Total phenol content was also affected by maturation, showing higher values in fruits ripened on the plant than under cold storage conditions. CONCLUSIONS: It was possible to observe a significant relationship between tomato fruit quality and grafting and relevant differences in fruit ripening conditions.

Enxertia, produção e qualidade de tomateiros cultivados em ambiente protegido / Grafting, production and quality of tomato growth in protected environment

Com o objetivo de verificar os efeitos da enxertia na produção e qualidade de tomateiros cultivados em ambiente protegido, conduziu-se um experimento em Viçosa, Minas Gerais (MG). Seis tratamentos foram avaliados no delineamento em blocos casualizados, com três repetições, resultantes da combinação de duas cultivares de tomate 'Débora' e 'Sta. Clara', enxertadas sobre os porta-enxertos 'Anchor T' e 'BGH 3472', além das duas cultivares de pés francos. A enxertia foi realizada por encostia. Os tratamentos enxertados com 'BGH 3472' e os pés francos Débora e Sta. Clara apresentaram as maiores produtividades comerciais. Não houve variação no teor de SST dos frutos, e o pH da polpa dos frutos foi menor nas combinações 'Anchor T'/Sta. Clara e 'BGH 3472'/Débora. Observou-se maior ATT nos frutos de Débora e menor nos frutos de Sta. Clara. A relação SST/ATT foi maior nos frutos da combinação 'Anchor T'/Sta. Clara, comparados aos frutos das combinações 'BGH 3472'/Débora e 'Anchor T'/Débora.

In order to check the effects of grafting in the production and quality of tomato grown in unheated greenhouse, an experiment was conducted in Viçosa, Minas Gerais State, Brazil. Six treatments were evaluated in randomized block design with three replications, resulting from the combination of two tomato cultivars Débora and Sta. Clara, grafted on two rootstocks 'Anchor T' and 'BGH 3472' in addition of the two ungrafted cultivars. The grafting method utilized was used. The treatments with the rootstock 'BGH 3472' and the cultivars 'Débora' and 'Sta. Clara' presented greatest commercial yields. There was no change in the content of SST. Fruit pH was smaller at the combinations 'Anchor T'/Sta.Clara and 'BGH 3472'/Débora Clara. It was observed greater ATT in the pulp of the fruits of Débora and smaller in the fruits of Sta. Clara. SST/ATT ratio was greater in fruits of the combination 'Anchor T'/Sta.Clara when compared with the fruits of the combinations between BGH 3472/Débora and BGH and 'Anchor T'/Débora.

Photocontrol of anthocyanin biosynthesis in tomato.

Juvenile anthocyanin biosynthesis has been studied in dark-grown seedlings of tomato (Lycopersicon esculentum Mill.) wild types (WTs) and photomorphogenic mutants. During a subsequent 24-hr period of monochromatic irradiation at different fluence rates of red light (R) the fluence-rate response relationships for induction of anthocyanin in all the WTs are similar, yet complex, showing a response at low fluence rates (LFRR) followed by a fluence rate-dependent high irradiance response (HIR). In the hypocotyl this response is restricted to the sub-epidermal layer of cells. The high-pigment-1 (hp-1) mutant exhibits a strong amplification of both response components. Theatroviolacea (atv) mutant shows strongest amplification of the HIR component. In contrast, a transgenic line overexpressing an oat phytochrome A gene (PHYA3 (+)) shows a most dramatic amplification of the LFRR component. The far-red light (FR)-insensitive (fri) mutant, deficient in phytochrome A (phyA), lacks the LFRR component whilst retaining a normal HIR. The temporarily R-insensitive (tri) mutant, deficient in phytochrome B1 (phyB1) retains the LFRR, but lacks the HIR. Thehp-1,fri andhp-1,tri double mutant, exhibit amplified, yet qualitatively similar responses to the monogenicfri andtri mutants. Thefri,tri double mutant lacks both response components in R, but a residual response to blue light (B) remains. Similarly, theaurea (au) mutant deficient in phytochrome chromophore biosynthesis and presumably all phytochromes, lacks both response components in the R and FR regions of the spectrum. Experiments at other wavelengths demonstrate that while there is only a small response in the FR spectral region (729 nm) in tomato, there is an appreciable HIR response in the near FR at 704 nm, which is retained in thetri mutant. This suggests that the labile phyA pool participates in the HIR at this wavelength. The intense pigmentation (Ip) mutant appears to be specifically deficient in the B1 induced anthocyanin biosynthesis. Adult plants, grown under fluorescent light/dark cycles, show a reduction of anthocyanin content of young developing leaves upon application of supplemtary or end-of-day FR. The involvement of different phytochrome species in anthocyanin biosynthesis based on micro-injection studies into theau mutant and studies using type specific phytochrome mutants is discussed.

Cation exchange in isolated xylem cell walls of tomato. I. Cd2+ and Rb+ exchange in adsorption experiments.

Purified xylem cell walls were prepared from isolated xylem bundles of tomato (an inbred line of Lycopersicon esculentum Mill, cv. Tiny Tim). Adsorption and exchange experiments were carried out with 115 Cd2+ , 82 Rb+ and 82 Br- . The application of γ-ray spectroscopy permitted the simultaneous measurement of several ions applied together. The cell-wall water volume was shown to be independent of the external pH and solution ionic strength, possibly due to the presence of lignin. The Donnan Free Space (DFS) volume could be determined as a constant 0.15 dm3 per kg cell-wall dry weight. Consequently, the total cell-wall cation exchange capacity (CEC) could be estimated based on the DFS volume, and amounted to approximately 1000 mol m-3 negative charges. The results of Cd2+ -Rb+ exchange experiments indicated an apparent CEC value of about 350-450 mol m-3 DFS, at external pH ∼ 4. These data are in agreement with earlier reports on xylem wall CEC, and indicate the weak acid characteristics of the charge groups. The rational selectivity coefficient RCdRb , of the cell wall was shown to depend on external ion fractions and ionic strength, with a maximum RCdRb of 450 at ionic Cd2+ fraction near 0.3, based at the smallest experimental ionic strength of the external solution. The adsorption of Cd2+ , applied at relatively high concentrations, was shown to be stimulated by simultaneous application of high Rb+ concentrations.