Enzymatic treatment to improve permeability and quality of cherry tomatoes for production of dried products.

BACKGROUND: Cherry tomatoes are nutritious and favored by consumers. Processing them into dried cherry tomatoes can prolong their storage life and improve their flavor. The pretreatment of tomato pericarp is crucial for the subsequent processing. However, the traditional physical and chemical treatments of tomato pericarp generally cause nutrient loss and environmental pollution. RESULTS: In this study, a novel enzymatic method for cherry tomatoes was performed using mixed enzymes containing cutinase, cellulase and pectinase. Results showed that the pericarp permeability of cherry tomatoes was effectively improved due to enzymatic treatment. Changes in the microscopic structure and composition of the cuticle were revealed. After treatment with different concentrations of enzymes, cherry tomatoes exhibited higher pericarp permeability and sensory quality to varying degrees. The lycopene content and total polyphenol content significantly increased 2.4- and 1.45-fold, respectively. In addition, the satisfactory effect of the six-time reuse of enzymes on cherry tomatoes could still reach the same level as the initial effect, which effectively reduced the cost of production. CONCLUSIONS: This study revealed for the first time that a mixed enzymatic treatment consisting of cutinase, pectinase and cellulase could effectively degrade the cuticle, enhance the pericarp permeability and improve the quality of cherry tomatoes, with the advantages of being mildly controllable and environmentally friendly, providing a new strategy for the processing of dried cherry tomatoes. © 2023 Society of Chemical Industry.

Transcriptomic analysis reveals that Bacillomycin D-C16 induces multiple pathways of disease resistance in cherry tomato.

BACKGROUND: Bacillomycin D-C16 can induce resistance in cherry tomato against pathogens; however, the underlying molecular mechanism is poorly understood. Here, the effect of Bacillomycin D-C16 on induction of disease resistance in cherry tomato was investigated using a transcriptomic analysis. RESULTS: Transcriptomic analysis revealed a series of obvious enrichment pathways. Bacillomycin D-C16 induced phenylpropanoid biosynthesis pathways and activated the synthesis of defense-related metabolites including phenolic acids and lignin. Moreover, Bacillomycin D-C16 triggered a defense response through both hormone signal transduction and plant-pathogen interactions pathways, and increased the transcription of several transcription factors (e.g., AP2/ERF, WRKY and MYB). These transcription factors might contribute to the further activated the expression of defense-related genes (PR1, PR10 and CHI) and stimulated the accumulation of H2O2. CONCLUSION: Bacillomycin D-C16 can induce resistance in cherry tomato by activating the phenylpropanoid biosynthesis pathway, hormone signal transduction pathway and plant-pathogen interactions pathway, thus activating comprehensive defense reaction against pathogen invasion. These results provided a new insight into the bio-preservation of cherry tomato by the Bacillomycin D-C16.

Tofu by-product soy whey substitutes urea: Reduced ammonia volatilization, enhanced soil fertility and improved fruit quality in cherry tomato production.

Soy whey is an abundant, nutrient-rich and safe wastewater produced in tofu processing, so it is necessary to valorize it instead of discarding it as sewage. Whether soy whey can be used as a fertilizer substitute for agricultural production is unclear. In this study, the effects of soy whey serving as a nitrogen source to substitute urea on soil NH3 volatilization, dissolved organic matter (DOM) components and cherry tomato qualities were investigated by soil column experiment. Results showed that the soil NH4+-N concentrations and pH values of the 50% soy whey fertilizer combined with 50% urea (50%-SW) and 100% soy whey fertilizer (100%-SW) treatments were lower than those of 100% urea treatment (CKU). Compared with CKU, 50%-SW and 100%-SW treatments increased the abundance of ammonia oxidizing bacteria (AOB) by 6.52-100.89%, protease activity by 66.22-83.78%, the contents of total organic carbon (TOC) by 16.97-35.64%, humification index (HIX) of soil DOM by 13.57-17.99%, and average weight per fruit of cherry tomato by 13.46-18.56%, respectively. Moreover, soy whey as liquid organic fertilizer reduced the soil NH3 volatilization by 18.65-25.27% and the fertilization cost by 25.94-51.87% compared with CKU. This study provides a promising option with economic and environmental benefits for soy whey utilization and cherry tomato production, which contributes to the win-win effectiveness of sustainable production for both the soy products industry and agriculture.

First Report of Fruit Rot Caused by Fusarium luffae in Cherry Tomato in China.

Tomato (Solanum lycopersicum L.) is a fruit of great economic value that is grown worldwide. In November 2022, fruit rot symptoms were observed in cherry tomatoes (cv. Qianxi) in Jinan City of Shandong Province, China. Six cherry tomato samples (four symptomatic and two asymptomatic) were collected from commercial fields (approximately 1.2 ha) where the incidence of the disease ranged from 5 to 10%. The core and surface of the infected fruit were colonized and covered with white mycelia. Tissue pieces (5 mm × 5 mm) from the junction of healthy and diseased samples were surface-disinfected with 75% ethanol for 3 min, followed by 10% sodium hypochlorite for 5 min, and washed three times with sterile water. Tissue pieces were cultured on potato dextrose agar (PDA containing 200 mg/L timentin) at 28°C for five days. Four fungal isolates with similar morphological characteristics were obtained from each sample. Two representative isolates were collected and purified using the single-spore method. After five days on PDA at 28°C, FL1 and FL2 colonies showed abundant white to cream colored aerial mycelia with an average growth rate of 5 mm/day. On carnation leaf agar, FL1 was characterized by falcate macroconidia with pronounced dorsiventral curvature containing three to eight tapered apical cells and foot-shaped basal cells ranging in size from 25 to 74 µm × 3.6 to 6.8 µm (n=50). Microconidia and chlamydospores were not observed. These morphological characteristics were consistent with the description of F. luffae (Wang et al. 2019). DNA was extracted using the CTAB method. The nucleotide sequences of the translation elongation factor 1-α gene (TEF1) and the second largest RNA polymerase II subunit (RPB2) were amplified using specific primers EF1/EF2 and RPB2F/R, respectively (O'Donnell et al. 1998, 2010). FL1 and FL2 sequences were deposited in GenBank (TEF1: OQ427345 and OQ427346, RPB2: OQ427347 and OQ427348). Polyphasic identification indicated 100% similarity of FL1 and FL2 to F. luffae. A combined dataset of TEF1 and RPB2 was aligned using MAFFT v.7, and phylogenetic analysis was performed in MEGA v.7.0 using the maximum likelihood method. The cherry tomato isolates (FL1 and FL2) clustered together with the F. luffae reference strain NRRL31167 (100% bootstrap) and were identified on a morphological and molecular basis as F. luffae belonging to the Fusarium incarnatum-equiseti species complex. F. luffae was the only pathogen recovered from the infected fruit. To test for pathogenicity, healthy cherry tomato fruit were inoculated in a greenhouse (28°C, 12/12 h light/dark cycle, 90% relative humidity), six by wounded inoculation and six by nonwounded inoculation) with 10 µL conidial suspensions of isolate FL1 at 1 × 106 conidia/mL. Six wounded-treated cherry tomato fruit were used for the control. All cherry tomatoes were kept in a growth chamber at 28℃ with 90% relative humidity. After seven days, the inside of the wound inoculated fruit began to rot, expanding toward the surface and producing white mycelia. Two diseased cherry tomatoes were randomly selected for tissue isolation and F. luffae was re-isolated showing the same morphology as the FL1 isolate, thus fulfilling Koch's postulates. The nonwounded inoculated fruits and control cherry tomatoes remained asymptomatic with no pathogens recovered. This indicates that the wound is an important way for F. luffae to invade tomato, and fruit rot is caused by F. luffae's infection of tomato. To the best of our knowledge, F. luffae has caused fruit rot in muskmelon (Zhang et al. 2022), but this is the first report of fruit rot disease in cherry tomatoes caused by F. luffae in China. Since cherry tomatoes are an important commercial crop in China, F. luffae infection has the potential to pose a threat to the industry.

First Report of Leaf Spot on Cherry Tomatoes Caused by Exserohilum rostratum in Hainan Province, China.

Cherry tomatoes (Lycopersicon esculentum var. cerasiforme) is the main tomato variety planted in Hainan Province, China and is prized for its nutritional value and sweet taste (Zheng et al. 2020). During October 2020 to February 2021, a leaf spot disease was observed on cherry tomatoes (cultivar Qianxi) in Chengmai, Hainan Province. The disease incidence was approximately 40% in each of three fields in Yongfa (19°76'-21°08'N, 110°21'-110°51'E). Leaves were initially chlorotic before developing black, irregular-shaped lesions on the leaf margins or tips. After several days, lesions expanded along the mid-vein to encompass the entire leaf. Then, the affected leaves turned gray-brown, leading to defoliation. Severely affected leaves became dry and necrotic. Leaf tissues of 10 diseased plants samples collected from the fields were surface sterilized in 70% ethanol for 30 s, 0.1% HgCl2 for 30 s, rinsed thrice with sterile distilled water for 30 s, placed on a modified potato dextrose agar (PDA) with 30 mg/liter of kanamycin sulfate, and incubated at 28°C in the dark for 3 to 5 days. Three fungal isolates were obtained from the diseased leaves by single-sporing. The mycelia on PDA were white and later became gray or dark gray after 3 to 4 days. Conidia were rostrate, straight to slightly curved, ellipsoidal to narrowly obclavate, dark brown, protuberant with a darker and thicker wall at the basal end. Conidia were 4 to 12 distoseptate and measured 63.92 ± 5.77 × 13.47 ± 1.22 µm (n= 50) Conidiophores were single, cylindrical, dark brown, geniculate, with swollen conidiogenous cells containing a acircular conidial scar. Morphological characteristics of the isolates were similar to those of Exserohilum rostratum (Cardona et al. 2008). A representative isolate (FQY-7) was used for pathogenicity and genomic studies. Genomic DNA was extracted from the mycelium of a representative isolate (FQY-7). The internal transcribed spacer (ITS) region, actin (act), translation elongation factor 1-alpha (tef1-α), glyceraldehydes 3-phos-phate dehydrogenase (gapdh) and ß-tubulin (tub2) genes were amplified with primers ITS1/ITS4 (White et al. 1990), Act1/Act4 (Voigt and Wöstemeyer 2000), EF1-728F/EF1-986R (Carbone and Kohn 1999), Gpd-1/Gpd-2 (Berbee et al. 1999) and T1 (O'Donnell and Cigelnik 1997) + Bt2b (Glass and Donaldson 1995). The consensus sequences (GenBank Accession No. MW036279 for ITS, MW133266 for act, MW133268 for tef1-α, MW133267 for gapdh, and MW133269 for tub2) were aligned using BLAST in GenBank obtaining 100%, 100%, 99%, 100%, and 99% identity to E. rostratum strain CBS706 (LT837842, LT837674, LT896663, LT882546, LT899350). Maximum likelihood analysis based on the combined five gene sequences was conducted under 1,000 bootstrap replicates. The Phylogenetic tree showed that FQY-7 and E. rostratum were located in one clade supported with 99% bootstrap values. Pathogenicity test was performed by depositing 10-µl droplets of a conidial suspension (1 × 106 per ml) into 5 noninoculated leaves (using a sterile needle) of 10 healthy 5-month-old cherry tomato (cv. Qianxi) plants. An equal number of artificially control leaves were received only sterile water to serve as a negative control. The test was conducted three times. Plants were kept at 28°C with 80% humidity and observed for symptoms every day. Two weeks after inoculation, all the inoculated plants showed symptoms of black spots similar to those observed in the field. No symptoms were observed on the controls. FQY-7 was successfully re-isolated from the inoculated leaves and confirmed by morphological characterization and molecular assays as described herein. To the best of our knowledge, this is the first report of leaf spot of cherry tomatoes caused by E. rostratum in China. Confirming the existence of this pathogen in this area will be useful to adopt effective field management measures to control this disease on cherry tomatoes. References: Berbee, M. L., et al. 1999. Mycologia 91:964. Cardona, R. et al. 2008. Bioagro 20:141. Carbone, I. and Kohn, L. M. 1999. Mycologia 91:553. Glass, N. L., and Donaldson, G. C. 1995. Appl. Environl. Microb. 61:1323. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. O'Donnell K., and Cigelnik, E. 1997. Mol. Phylogenet. Evol. 7:103. Voigt, K., and Wöstemeyer, J. 2000. Microbiol. Res. J. 155:179. Zheng J., et al. 2020. Guangdong Agr. Sci. 47:212. The author(s) declare no conflict of interest.

Verification of Commercial Near-Infrared Spectroscopy Measurement and Fresh Weight Diversity Modeling in Brix% for Small Tomato Fruits with Various Cultivars and Growth Conditions.

The use of non-destructive commercial near-infrared (NIR) spectroscopy to estimate Brix% was verified using all samples of cherry tomato 'TY Chika', currant tomato 'Microbeads', and the M&S or market-purchased and supplemental local source tomatoes. Additionally, the relationship between fresh weight and Brix% of all samples was examined. These tomatoes had a diversity of cultivars, growing methods, harvest timing, and production locations and varied widely from 4.0% to 14.2% for Brix% and 1.25 g to 95.84 g for fresh weight. Regardless of the diversity of all samples, it was revealed that the refractometer-based Brix% (y) was practically estimated from the NIR-derived Brix% value (x) using a relationship of y = x (RMSE = 0.747 Brix%) after only a one-time calibration for the NIR spectrometer offset. An inverse relationship between fresh weight and Brix% could be modeled using a hyperbolic curve fit, and the model showed an R2 of 0.809 except for 'Microbeads'. The Brix% of 'TY Chika' was highest on average (9.5%) and had a large difference from 6.2 to 14.2% among the samples. Data distribution of cherry tomato groups such as 'TY Chika' and M&S cherry tomatoes was closer, indicating a roughly linear correlation between fresh weight and Brix%.

Systematic analysis of the sugar accumulation mechanism in sucrose- and hexose- accumulating cherry tomato fruits.

BACKGROUND: Sugar content is an important indicator of fruit quality. Except for a few wild tomato species that accumulate sucrose in the fruits, most cultivated tomato species accumulate hexose. Although several studies have focused on wild sucrose-accumulating tomato, the sucrose accumulation mechanism is still unclear. RESULTS: Here, two homozygous inbred cherry tomato lines ('TB0023' and 'TB0278', which accumulated sucrose and hexose, respectively) were selected to analyze the sugar accumulation mechanism. Carbohydrate analysis, cytological observation, gene expression and enzyme activity analysis and proteomics methods were used in this study. The results indicated that glucose and fructose were absolutely dominant in the soluble sugar content of hexose-accumulating cherry tomato fruit, while sucrose and a certain proportion of hexose were the main forms of soluble sugar in sucrose-accumulating cherry tomato fruit. The phloem unloading pathway of the hexose-accumulating cherry tomato fruit switched from symplastic to apoplastic during fruit development, and the sucrose-accumulating cherry tomato probably had a mixed unloading pathway involving the symplastic and apoplastic. High activity of acid invertase (AI), sucrose phosphate synthase (SPS), sucrose synthase (SS) and sugar transporters LeSUT1, SlSWEET2a and SlSWEET12c were important factors for hexose accumulation in the hexose-accumulating cherry tomato fruit, while LeSUT2, SPS, SS, SlSWEET1b, SlSWEET5b, SlSWEET11b, SlSWEET7a, SlSWEET14 were responsible for solute sugar accumulation in the sucrose-accumulating cherry tomato. CONCLUSIONS: This study provides detailed evidence for elucidation of the tomato sugar accumulation mechanism from the perspective of cell structure, physiology and molecular biology, providing a theoretical basis for the improvement of tomato quality and aiding the utilization of tomato genetic resources.

Network response of two cherry tomato (Lycopersicon esculentum) cultivars to Cadmium stress as revealed by transcriptome analysis.

Soil cadmium (Cd) contamination severely threatens human health. Therefore, screening and breeding low-Cd absorption cultivars of cherry tomato (Solanum lycopersicum L.) is essential to restrict human Cd intake. In this study, a hydroponic experiment was conducted to perform a comparative transcriptome analysis of the leaves of two cherry tomato cultivars with different Cd contents under different Cd stress (0, 10, and 50 µM), for the purpose of exploring the differences in the transcriptional responses to Cd stress between the two cultivars. Our results revealed that the Cd content in the leaves of HLZ (Hanluzhe; a low-Cd accumulation cultivar) was significantly lower than that in the leaves of LFC (Lvfeicui; a high-Cd accumulation cultivar). Transcriptome analysis showed that the different expression genes (DEGs) were mainly involved in plant hormone signal transduction, antioxidant enzymes, cell wall biosynthesis, and metal transportation. In the LFC leaves, DEGs in the IAA signal transduction and antioxidant enzymes exhibited higher transcription levels. However, the DEGs in the ETH signal transduction demonstrated a lower transcription level compared to that of HLZ. Over-expressed genes in the pectin biosynthesis and pectin methylesterase (PME) of the LFC leaves might result in the trapping of Cd by increased levels of low-methylated pectin around the cell wall. Furthermore, Cd transporter genes, such as HMA5, NRAMP6, CAX3, ABCC3, and PDR1, were up-regulated in the HLZ leaves, indicating that the HLZ cultivar comprised an active Cd transport capacity from apoplast to vacuolar. This may contribute to the low Cd concentration observed in the HLZ leaves. Overall, our study provides a molecular basis for tomato screening and breeding.

Inhibitory effects and mechanisms of vanillin on gray mold and black rot of cherry tomatoes.

Vanillin is a natural antimicrobial agent; however, there are few reports on its antifungal effect on postharvest pathogenic fungi. This study aimed to investigate the in vivo and in vitro antifungal activities of vanillin against gray mold (caused by B. cinerea) and black rot (caused by A. alternata) of cherry tomato fruit and to explain its possible mechanism of action. Vanillin strongly inhibits Botrytis cinerea and Alternaria alternata mycelial growth, spore germination, and germ tube elongation in a concentration-dependent manner (P<0.05). In vivo experiments showed that 4000 mg L-1 vanillin treatment inhibited cherry tomato gray mold and black rot occurrence. Besides, intercellular electrolytes, soluble proteins, and soluble sugars leakage indicated that 50 or 100 mg L-1 vanillin treatment increased Botrytis cinerea and Alternaria alternata membrane permeability. The increase of malondialdehyde and hydrogen peroxide contents confirmed that 50 or 100 mg L-1 vanillin treatment damages the pathogen membranes. Importantly, vanillin treatment inhibited the pathogenicity-related enzyme activities of the two pathogens to reduce their infection ability, among them PL enzyme activity in A. alternata was most inhibited, reducing by 94.7 % at 6 h treated with 100 mg L-1 vanillin. The hyphae morphology of the two pathogens changed, the mycelia were severely damaged, and the hyphae surface was deformed, shrunk, or even broken after 100 mg L-1 vanillin treatment. In summary, vanillin had a substantial inhibitory effect on postharvest gray mold and black rot in cherry tomato fruit. Therefore, vanillin can be an effective alternative to prevent and control cherry tomato postharvest diseases.

Iturin A Induces Resistance and Improves the Quality and Safety of Harvested Cherry Tomato.

The soft rot disease caused by Rhizopus stolonifer is an important disease in cherry tomato fruit. In this study, the effect of iturin A on soft rot of cherry tomato and its influence on the storage quality of cherry tomato fruit were investigated. The results showed that 512 µg/mL of iturin A could effectively inhibit the incidence of soft rot of cherry tomato fruit. It was found that iturin A could induce the activity of resistance-related enzymes including phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), glucanase (GLU), and chitinase (CHI), and active oxygen-related enzymes including ascorbate peroxidases (APX), superoxide dismutases (SOD), catalases (CAT), and glutathione reductase (GR) of cherry tomato fruit. In addition, iturin A treatment could slow down the weight loss of cherry tomato and soften the fruit. These results indicated that iturin A could retard the decay and improve the quality of cherry tomato fruit by both the inhibition growth of R. stolonifera and the inducing the resistance.

Exogenous 24-epibrassinolide activates detoxification enzymes to promote degradation of boscalid in cherry tomatoes.

BACKGROUND: Boscalid is often used to extend the storage time of postharvest cherry tomato. Pesticide residue has become an issue of food safety. This study sought to investigate the spatial distribution of boscalid residue in cherry tomato fruits and to determine the effect of 24-epibrassinolide (EBR) in promoting boscalid degradation. RESULTS: Boscalid could quickly penetrate into cherry tomatoes, but mainly remained in the peel. The migration of boscalid from the peel into the core was a time-consuming and complex process during storage. After 72 h, boscalid residues in the pulp and the core began to accumulate gradually. The exogenous application of EBR activated peroxidase, glutathione reductase and glutathione S-transferase, and effectively promoted the degradation of boscalid by a maximum decrease of 44.8% in peel, 54.0% in pulp and 71.2% in core. CONCLUSION: As one of the common pesticides, boscalid had a strong ability to enter the cherry tomato and thus become a potential risk for public consumption. Therefore, rational use of pesticides is recommended. The results of this study indicate that the possible risk of boscalid residue could be alleviated by EBR pretreatment through activating detoxification enzymes. © 2020 Society of Chemical Industry.

Effect of combined Bacillomycin D and chitosan on growth of Rhizopus stolonifer and Botrytis cinerea and cherry tomato preservation.

BACKGROUND: Synthetic fungicides are most commonly used for controlling postharvest disease of fruit, although they can cause the emergence of drug-resistant strains, environmental pollution and fruit safety issues. Bacillomycin D (BD), a novel antifungal lipopeptide, and chitosan (CTS) are applied for the preservation of cherry tomato. RESULTS: The combination of BD and CTS showed an additive inhibition on the growth of Rhizopus stolonifer and Botrytis cinerea compared to that of its individual compound. In addition, BD + CTS reduced the incidence of soft rot and gray mold in cherry tomato caused by R. stolonifer and B. cinerea, respectively. Tomato treated with BD + CTS exhibited a lower weight loss and higher firmness and higher contents of total soluble solids, titratable acidity and ascorbic acid compared to those treated with sterile water (control). The kinetics models demonstrated that the shelf life of cherry tomato treated with BD + CTS could be extended by approximately 15 days longer than the control. CONCLUSION: The utilization of BD + CTS provided a novel strategy for reducing postharvest fungal rot and maintaining the storage quality of cherry tomato. © 2020 Society of Chemical Industry.

Chlorogenic acid induces ROS-dependent apoptosis in Fusarium fujikuroi and decreases the postharvest rot of cherry tomato.

Chlorogenic acid is a plant polyphenol with antioxidant and antimicrobial activities. Fusarium fujikuroi is a fungal pathogen that causes many vegetables and fruits, including tomato, to rot. The effects of chlorogenic acid on the development of Fusarium rot of cherry tomato fruit were examined in the present study. Results showed that conidial germination, germ tube elongation, cell viability, and mycelial growth of F. fujikuroi were all significantly inhibited by chlorogenic acid. Chlorogenic acid stimulated the accumulation of reactive oxygen species (ROS), leading to cell apoptosis in F. fujikuroi. The addition of N-acetylcysteine partially recovered the mycelial growth, implying the antifungal activity of chlorogenic acid is related to a ROS burst. The application of chlorogenic acid decreased disease incidence and severity in cherry tomato fruit in a concentration-dependent manner. Taken together, these results suggest that chlorogenic acid inhibits the postharvest rot of cherry tomato fruit caused by F. fujikuroi by inducing cellular oxidative stress in the pathogen.

Pichia kudriavzevii retards fungal decay by influencing the fungal community succession during cherry tomato fruit storage.

In this study, P. kudriavzevii was isolated and identified as an effective antagonistic yeast, which could significantly inhibit the rotting rate, weight loss, and delay the color change, with no effect on total soluble solids (TSS), titratable acid (TA), or firmness during cherry tomato storage. High-throughput sequencing was used to survey the effect of P. kudriavzevii on fungal community throughout cold storage. The results showed that the biological succession of predominant pathogens was disrupted by P. kudriavzevii. The abundance of Botrytis and Alternaria was higher in the control than upon P. kudriavzevii treatment at 28 d, but some yeast genera such as Naganishia, Wickerhamomyces, and Cutaneotrichosporon at 14 d, Pichia and Sporidiobolus at 21 d, and Cystofilobasidium at 28 d, had relatively higher abundances in P. kudriavzevii treatments than the control. Oddly, as an antagonist agent, P. kudriavzevii was not the dominant population, indicating that altering the course of succession of the fungal community may be an effective mechanism of antagonistic yeast. Furthermore, the total network correlation analysis of fungal community revealed that the community development was more dependent on similarities in function than on taxonomic relationships.

Sodium pheophorbide a controls cherry tomato gray mold (Botrytis cinerea) by destroying fungal cell structure and enhancing disease resistance-related enzyme activities in fruit.

Sodium pheophorbide a (SPA) is a natural photosensitizer. The present study investigated the antifungal activity and mechanism of SPA against Botrytis cinerea in vitro and in vivo. Its inhibitory effect was studied on the spore germination and mycelial growth of B. cinerea. The effects of SPA on cell wall integrity, cell membrane permeability, and mycelial morphology of B. cinerea were also determined. Additionally, how SPA effected B. cinerea in vivo was evaluated using cherry tomato fruit. The results showed that SPA effectively inhibited the spore germination and mycelial growth of B. cinerea under light conditions (4000 lx). SPA significantly affected both cell wall integrity and cell membrane permeability (P < .05). In addition, SEM analysis suggested that B. cinerea treated with SPA (12.134 mg/mL) showed abnormal mycelial morphology, including atrophy, collapse, flattening, and mycelial wall dissolution. In vivo tests showed that SPA could increase the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) significantly (P < .05); however, SPA had no significant effect on phenylalanine ammonia lyase (PAL) activity. In short, SPA could destroy the fungal cell structure and enhance disease resistance-related enzyme activity in cherry tomatoes, thereby controlling cherry tomato gray mold.

Physicochemical properties and shelf-life of low-fat pork sausages wrapped with active film manufactured by sodium alginate and cherry tomato powder.

OBJECTIVE: This study was carried out to investigate physicochemical properties, and antioxidant and antimicrobial activities of low-fat sausages (LFSs) covered with sodium alginate (SA) film alone and with powder film (TSA-film) formed by cross-linking cherry tomato powder (CTP) and SA with calcium chloride (CaCl2). METHODS: Sausages covered with the biodegradable film were assessed based on the measurement of pH, color (L*, a*, b*), proximate analysis, expressive moisture (EM), texture profile analysis, total plate counts (TPC), violet red bile, and 2-Thiobarbituric acid reactive substances (TBARS) during storage under refrigeration. LFSs wrapped with TSA-film were compared with those wrapped with SA-film and without film (control) during storage at 10°C for 35 days. RESULTS: The LFSs covered with the mixed film had lower pH, lightness (L*), EM%, TBARS, and TPC, but lower yellowness (b*) and hardness values than those wrapped with TSA-film alone. CONCLUSION: Lipid oxidation and microbial growth was retarded in sausages covered with biodegradable films, especially multiple films as compared to single film, thereby resulting in extended shelf-life of the LFSs.

Bacillomycin D inhibits growth of Rhizopus stolonifer and induces defense-related mechanism in cherry tomato.

The inhibitory effect of Bacillomycin D, a cyclic lipopeptide, on Rhizopus stolonifer colonization of cherry tomato was studied, and its possible mechanism of action was explored. Bacillomycin D showed a direct inhibitory effect on R. stolonifer spore germination and mycelial growth in vitro. It conferred both a direct inhibitory effect on R. stolonifer growth in cherry tomato in vivo and induced host resistance in cherry tomato. Moreover, Bacillomycin D treatment significantly increased the activities of plant defense-related enzymes, including chitinase (CHI), ß-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), and peroxidase (POD). Real-time PCR (RT-PCR) showed that defense-related genes involved in the salicylic acid defense signaling pathway and genes encoding pathogenesis-related proteins were up-regulated in Bacillomycin D treatment. Furthermore, Bacillomycin D-C16 resulted in direct inhibition and a remarkable induced resistance to R. stolonifer which was higher than as induced by Bacillomycin D-C14. Together, the data indicated that Bacillomycin D can control the growth of R. stolonifer through both the direct inhibition of the fungus and the activation of defense-related genes and enzymes in cherry tomato.

Comparative Chemical Compositions of Fresh and Stored Vesuvian PDO "Pomodorino Del Piennolo" Tomato and the Ciliegino Variety.

The Vesuvian Piennolo cherry tomato (Lycopersicon esculentum Miller) (PdP) is an old and typical variety grown in the Campania region (Italy). PdP is referred to as a long-storage tomato due to its thick and coriaceous skin that allows long post-harvest storage and it has been granted Protected Designation of Origin (PDO) status since 2009. In this study, the chemical composition, focusing in particular on organic acids, antioxidant molecules and volatile compounds, were investigated in PdP and compared to another typical variety in Campania, the Ciliegino tomato (CIL). Chemical characterization was evaluated for both the CIL and PdP varieties during storage in the same environmental conditions until deterioration of 50% of the fruits; deterioration occurred in PdP after 6 months and in CIL tomatoes after 1 month. The results demonstrated variation in the chemical profiles of both varieties with storage length. Particularly, the PdP variety appears richer in antioxidants compounds (i.e., chlorogenic acids and lycopene) and organic acids (i.e., glutamic and malic acids) than does CIL. Additionally, both varieties display different profiles of volatile bioactive compounds and they are differently influenced by the storage time. The results indicate a typical chemical composition of this long-storage tomato closely linked to the geographic origin area.

Hot air treatment reduces postharvest decay and delays softening of cherry tomato by regulating gene expression and activities of cell wall-degrading enzymes.

BACKGROUND: Fruit softening facilitates pathogen infection and postharvest decay, leading to the reduction of shelf-life. Hot air (HA) treatment at 38 °C for 12 h is effective in reducing postharvest disease and chilling injury of tomato fruit. To explore the effect and mechanism of HA treatment on reducing postharvest decay and softening of cherry tomato, fruit at the mature green stage were treated with HA and then stored at 20 °C for 15 days. Changes in natural decay incidence, firmness, cell wall compositions, activities and gene expression of cell wall-degrading enzymes of cherry tomatoes were assessed. RESULTS: HA treatment reduced natural decay incidence, postponed the firmness decline, inhibited the respiration rate and ethylene production, and retarded pectin solubilisation and cellulose degradation of cherry tomatoes. Enzymatic activities and gene expression of pectin methylesterase, polygalacturonase, cellulase and ß-galactosidase were inhibited by HA treatment. In addition, the gene expression of LeEXP1 was reduced, while LeEXT was up-regulated after HA treatment. CONCLUSIONS: Our findings suggested that HA treatment could inhibit cell wall degradation and postpone softening of cherry tomatoes by regulating gene expression and activities of cell wall-degrading enzymes, resulting in the reduction of postharvest decay. © 2017 Society of Chemical Industry.

Biocontrol activity of a cold-adapted yeast from Tibet against gray mold in cherry tomato and its action mechanism.

Cold-adapted biocontrol yeast was selected from four yeast isolates from Tibet against gray mold of cherry tomato in cold storage. The strain numbered LB2 showed the best biocontrol activity and identified as Cryptococcus laurentii. Competition for nutrient, space, and induced fruit resistance was also its antagonistic mechanism. Compared with C. laurentii from sea-level place, the reason why LB2 had a better biocontrol activity was studied. More trehalose and proline in cell of LB2 made it exhibit a better cellular activity at low temperature, such as higher population dynamics in the wounds of cherry tomato and more biocontrol-related enzyme secretion, chitinase and ß-glucanase. The better oxidative stress tolerance was another characteristic of LB2. Maybe because of the ideal culture condition, there was no obvious difference between these two yeasts in the growth in vitro test at low temperature. Although the same phenomenon existed in the low pH stress test, LB2 still had higher cell concentration under this stress. Comparative transcriptomics method was also applied to analyze the cell activity of LB2 and C. laurentii at different temperatures. The results showed that more active response in the intracellular structure and intracellular metabolic process to cold temperature made LB2 had a better activity. The present study indicated a possibility to select cold-adapted biocontrol yeast from Tibet and also showed its primary action mechanism.