New insights into the role of cyanide in the promotion of seed germination in tomato

Background Cyanide is a natural metabolite that exists widely in plants, and it is speculated to be involved in the regulation of various growth and development processes of plants in addition to being regarded as toxic waste. Previous studies have shown that exogenous cyanide treatment helps to improve seed germination, but the mechanism is still unclear. In this study, tomato (Solanum lycopersicum cv. Alisa Craig) was used as the material, and the effects of cyanide pretreatment at different concentrations on tomato seed germination were investigated. Results The results showed that exogenous application of a lower concentration of cyanide (10 μmol/L KCN) for 12 h strongly increased the tomato seed germination rate. RNA-Seq showed that compared with the control, a total of 15,418 differentially expressed genes (P<0.05) were obtained after pretreatment with KCN for 12 h, and in the next 12 h, a total of 13,425 differentially expressed genes (P<0.05) were regulated. GO and KEGG analyses demonstrated that exogenous KCN pretreatment was involved in regulating the expression (mainly downregulation) of seed storage proteins, thereby accelerating the degradation of stored proteins for seed germination. In addition, KCN pretreatment was also involved in stimulating glycolysis, the TCA cycle and oxidative phosphorylation. Notably, it is shown that KCN acted on the regulation of plant hormone biosynthesis and perception, i.e., down-regulated the gene expression of ABA biosynthesis and signal transduction, but up-regulated the expression of genes related to GA biosynthesis and response. Consistent with this, plant hormone measurements confirmed that the levels of ABA were reduced, but GA levels were induced after pretreatment with KCN. Conclusion These findings provide new insights into the regulation of seed germination by cyanide, that is cyanide-mediated seed germination occurs in a time- and dose-dependent manner, and is related to the mobilization of energy metabolism and the regulation of some plant hormone signals.

PHOTOSYNTHETIC INOCULANTS FOR PROMOTING SEED GERMINATION AND DEVELOPMENT OF TOMATO PLANTS

Microalgae and cyanobacteria are a potentially sustainable alternative for the improvement and protection of agricultural crops. Mineral fertilizers raise environmental and health issues. and current agricultural practices depend to a large extent on the application of fertilizers and pesticides. In this study. we examined the effect of cyanobacteria and microalgae on tomato seed germination. seedling growth. green and dry biomass. gas exchange from leaves (plant photosynthesis and transpiration). and the chlorophyll content of leaves (chlorophyll a. b and carotene). as well as on the soil respiration process. The obtained results highlight higher values of green and dry biomass in the variants inoculated with cyanobacteria and microalgae compared to the control variant and comparable to the values obtained in the technologically fertilized variants. Tomato seedlings showed higher photosynthesis values compared to the control and compared to the technologically fertilized variant in the soil of the pea plot (7.06 μmol CO2 / m2 / s compared to 6.33μmol CO2 / m2 / s in the control variant and 7.06 μmol CO2 / m2 / s in the technologically fertilized version). And in the case of the soil in the museum plot. the values of photosynthesis in the version with the inoculum of cyanobacteria and microalgae were statistically assured compared to the control.

A long-amplicon viability-qPCR test for quantifying living pathogens that cause bacterial spot in tomato seed

Bacterial spot is one of the most serious diseases of tomato. It is caused by four species of Xanthomonas: X. euvesicatoria, X. gardneri, X. perforans, and X. vesicatoria. Contaminated and/or infected seed can serve as a major source of inoculum for this disease. The use of certified pathogen-free seed is one of the primary management practices to reduce the inoculum load in commercial production. Current seed testing protocols rely mainly on plating the seed extract and conventional PCR, however, the plating method cannot detect viable but non-culturable cells and the conventional PCR assay has limited capability to differentiate DNA extracted from viable versus dead bacterial cells. To improve the sensitivity and specificity of the tomato seed testing method for the bacterial spot pathogens, a long-amplicon qPCR assay coupled with propidium monoazide (PMA-qPCR) was developed to quantify selectively the four pathogenic Xanthomonas species in tomato seed. The optimized PMA-qPCR procedure was evaluated on pure bacterial suspensions, bacteria-spiked seed extracts, and seed extracts of inoculated and naturally-infected seed. A crude DNA extraction protocol also was developed and PMA-qPCR with crude bacterial DNA extracts resulted in accurate quantification of 104-108 CFU/ml of viable bacteria when mixed with dead cells at concentrations as high as 107 CFU/ml in the seed extracts. With DNA purified from concentrated seed extracts, the PMA-qPCR assay was able to detect DNA of the target pathogens in seed samples spiked with ≥75 CFU/ml (~0.5 CFU/seed) of the viable pathogens. Latent class analysis of the inoculated and naturally-infected seed samples showed that the PMA-qPCR assay had greater sensitivity than plating the seed extracts on the semi-selective MTMB and CKTM media for all four target species. Being much faster and more sensitive than dilution plating, the PMA-qPCR assay has a promising potential to serve as a standalone tool or used in combination with the plating method to improve tomato seed testing and advance the production of clean seed.

Discrimination of tomato seeds belonging to different cultivars using machine learning

This study was aimed at developing the discriminant models for distinguishing the tomato seeds based on texture parameters of the outer surface of seeds calculated from the images (scans) converted to individual color channels R, G, B, L, a, b, X, Y, Z. The seeds of tomatoes ‘Green Zebra’, ‘Ożarowski’, ‘Pineapple’, Sacher F1 and Sandoline F1 were discriminated in pairs. The highest results were observed for models built based on sets of textures selected individually from color channels R, L and X and sets of textures selected from all color channels. In all cases, the tomato seeds ‘Green Zebra’ and ‘Ożarowski’ were discriminated with the highest average accuracy equal to 97% for the Multilayer Perceptron classifier and 96.25% for Random Forest for color channel R, 95.25% (Multilayer Perceptron) and 95% (Random Forest) for color channel L, 93% (Multilayer Perceptron) and 95% (Random Forest) for color channel X, 99.75% (Multilayer Perceptron) and 99.5% (Random Forest) for a set of textures selected from all color channels (R, G, B, L, a, b, X, Y, X). The highest average accuracies for other pairs of cultivars reached 98.25% for ‘Ożarowski’ vs. Sacher F1, 95.75% for ‘Pineapple’ vs. Sandoline F1, 97.5% for ‘Green Zebra’ vs. Sandoline F1, 97.25% for Sacher F1 vs. Sandoline F1 for models built based on textures selected from all color channels. The obtained results may be used in practice for the identification of cultivar of tomato seeds. The developed models allow to distinguish the tomato seed cultivars in an objective and fast way using digital image processing. The results confirmed the usefulness of texture parameters of the outer surface of tomato seeds for classification purposes. The discriminative models allow to obtain a very high probability and may be applied to authenticate and detect seed adulteration.

Seed Priming With an Animal-derived Protein Hydrolysate Improves Drought Tolerance of Tomato Seeds by Enhancing Reserve Mobilization, Osmotic Adjustment, and Antioxidant Mechanism

Purpose Protein hydrolysates obtained from agro-industrial byproducts have received much attentions due to their positive roles in regulating plant responses to environmental stresses. However, little is known about the roles of animal protein hydrolysates in mediating seed drought tolerance and the underlying mechanism. Here, the effects of seed priming with pig blood protein hydrolysates (PP) on tomato seed germination and seedling growth under drought stress were investigated. Methods Tomato seeds were soaked with different concentrations of PP solutions for 24 h, and then transferred to filter paper moistened with distilled water or 10% PEG-6000 solution in Petri dish. The germination traits, seeding growth, reserve mobilization, osmolytes, and antioxidant system were determined.Results PP priming effectively alleviated the reduction in seed germination traits, resulting in improved tomato seedling growth under drought stress. PP priming enhanced amylase and sucrose synthase activities, soluble sugar, soluble protein, and free amino acid levels, thereby promoting reserve mobilization in seeds. Moreover, PP priming also reduces osmotic toxicity by increasing the accumulation of proline, soluble protein, and soluble sugar. Drought stress substantially enhanced the production of ROS and subsequent increases in MDA and Evans blue uptake, which were significantly alleviated after PP priming by improving the activities of SOD, POD, and CAT, and non-enzymatic antioxidants. Conclusion PP priming is a feasible method for improving tomato seed germination and seedling growth under drought stress by enhancing reserve mobilization, osmolyte accumulation, and antioxidant systems.

Evaluation of droplet digital PCR for the detection of black canker disease in tomato

Clavibacter michiganensis subsp. michiganensis (Cmm), the cause of bacterial canker disease, is one of the most destructive pathogens in greenhouse and field tomato. The pathogen is now present in all main production areas of tomato and is quite widely distributed in the EPPO（European and Mediterranean Plant Protection Organization）region. The inspection and quarantine of the plant pathogens relies heavily on accurate detection tools. Primers and probes reported in previous studies do not distinguish the Cmm pathogen from other closely related subspecies of C. michiganensis, especially the non-pathogenic subspecies that were identified from tomato seeds recently. Here, we have developed a droplet digital polymerase chain reaction (ddPCR) method for the identification of this specific bacterium with primers/TaqMan probe set designed based on the pat-1 gene of Cmm. This new primers/probe set has been evaluated by qPCRthe real time PCR（qPCR） and ddPCR. The detection results suggest that the ddPCR method established in this study was highly specific for the target strains. The result showed the positive amplification for all 5 Cmm strains，and no amplification was observed for the other 43 tested bacteria, including the closely related C. michiganensis strains. The detection threshold of ddPCR was 10.8 CFU/mL for both pure Cmm cell suspensions and infected tomato seed, which was 100 times-fold more sensitive than that of the real-time PCR (qPCR ) performed using the same primers and probe. The data obtained suggest that our established ddPCR could detect Cmm even with low bacteria load, which could facilitate both Cmm inspection for pathogen quarantine and the routine pathogen detection for disease control of black canker in tomato.

Lycoperoside H, a Tomato Seed Saponin, Improves Epidermal Dehydration by Increasing Ceramide in the Stratum Corneum and Steroidal Anti-Inflammatory Effect

Tomatoes are widely consumed, however, studies on tomato seeds are limited. In this study, we isolated 11 compounds including saponins and flavonol glycosides from tomato seeds and evaluated their effects on epidermal hydration. Among the isolated compounds, tomato seed saponins (10 µM) significantly increased the mRNA expression of proteins related to epidermal hydration, including filaggrin, involucrin, and enzymes for ceramide synthesis, by 1.32- to 1.91-fold compared with the control in HaCaT cells. Tomato seed saponins (10 µM) also decreased transepidermal water loss by 7 to 13 g/m2·h in the reconstructed human epidermal keratinization (RHEK) models. Quantitative analysis of the ceramide content in the stratum corneum (SC) revealed that lycoperoside H (1–10 µM) is a promising candidate to stimulate ceramide synthesis via the upregulation of ceramide synthase-3, glucosylceramide synthase, and β-glucocerebrosidase, which led to an increase in the total SC ceramides (approximately 1.5-fold) in concert with ceramide (NP) (approximately 2-fold) in the RHEK models. Evaluation of the anti-inflammatory and anti-allergic effects of lycoperoside H demonstrated that lycoperoside H is suggested to act as a partial agonist of the glucocorticoid receptor and exhibits anti-inflammatory effects (10 mg/kg in animal test). These findings indicate that lycoperoside H can improve epidermal dehydration and suppress inflammation by increasing SC ceramide and steroidal anti-inflammatory activity.

Tarhana Üretiminde Kullanılan Buğday Unu Alternatifleri

The aim of this study was to investigate the possibilities of using various flour substitutes instead of wheat flour in the production of tarhana, which is a fermented food. In the studies examined for this purpose, various legume and cereal flours (oats, quinoa, lupine, wheat germ, chickpeas, beans, corn, rice, buckwheat and lentil flours), tomato paste production waste (tomato seed, tomato pulp, pepper seed, pepper pulp), potato starch, chestnut flour, carob flour, hazelnut pulp, almond pulp, and fish meat were substituted for wheat flour. With these substitutions used instead of wheat flour in the production of tarhana, it was aimed to increase the nutritional properties of the tarhana, improve its sensory properties and quality features. Alternative flours used in the production of tarhana were investigated in this study. According to the results obtained from the compiled studies, tarhana produced with the use of substitute flour will be an alternative to demand of consumers with high functional, natural and nutritional quality.