• Natural Product Sciences
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• v.24 no.4
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• pp.272-283
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• 2018

The root-knot nematode, Meloidogyne incognita caused a serious damage to many plants. The phenolic components of the leaves of Schinus terebinthifolius were investigated as potential nematicidal agents for M. incognita. Nine compounds were isolated and characterized as viz., 1,2,3,4,6-pentagalloyl glucose (1), kaempferol-3-O-${\alpha}$-L-rhamnoside (Afzelin) (2), quercetin-3-O-${\alpha}$-L-rhamnoside (Quercetrin) (3), myricetin (4), myricetin-3-O-${\alpha}$-L-rhamnoside (Myricetrin) (5), methylgallate (6), protocatechuic acid (7), quercetin (8), and gallic acid (9) using nuclear magnetic resonance (NMR) spectroscopy. Compound 1 showed pronounced nematicidal activity compared to Oxamyl as a positive control. It showed the lowest eggs-hatchability (34%) and the highest mortality in nematode population (21% after 72 hours of treatment) at a concentration of $200{\mu}g/mL$. It exhibited the best suppressed total nematode population, root galling and number of eggmasses in infected tomato plants. The total carbohydrates and proteins were also significantly induced by 1 with reduction in total phenolics and increase in defense-related proteins. Thus, compound 1 could be a promising, more safe and effective natural nematicidal agent for the control of root-knot nematodes.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.152-158
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• 2008

A peculiar virus-like disease of tomato showing yellow mosaic and necrotic spots on leaves and necrosis on veins, petioles and stems was observed at the Tomato Experimental Station (TES), Buyeo, Chungcheongnamdo, Korea. The disease incidence at TES fields ranged from 21 to 35% infecting different tomato cultivars. For this reason, to identify the virus infecting tomato and to characterize the virus based on biology, serology, cytology and at molecular level. Here, leaf samples were randomly collected from different infected tomato cultivars at TES fields and greenhouses and tested by ELISA using Pepper mottle virus (PePMoV) and Tomato mosaic virus (ToMV) antisera. Infected saps were mechanically inoculated in different host plants to test for pathogenicity, symptomatology and host ranges. Infected tissues and ultrathin sections were examined by electron microscopy. Finally, putative coat protein and 3'-untranslated region (CP/3'-UTR) fragment was amplified and cloned for sequence determination and analyzed its genetic relationship to existing PepMoV and PVY sequences at the Genbank. Results showed 69% of the samples were positive with PepMoV, 13% with ToMV and 19 % were doubly infected with PepMoV and ToMV. Symptoms greatly varied from different host plants inoculated with tomato leaf sap infected with PepMoV alone and discussed in detailed in this paper. Electron microscopy from infected tissues showed filamentous particles of 720-750nm in length, a typical morphology and size of PepMoV. In addition, cylindrical inclusion bodies, pinwheels, scrolls and laminates with masses of fibrillar inclusions were also found in ultrathin sections. Alignment of the sequences of the CP/3'-UTR revealed >96% sequence identity with PepMoV and only <61% with PVY. Taken together, all these evidences presented clearly indicated that the causal agent infecting tomato at TES was PepMoV and we designated this PepMoV infecting tomato as Tom-sd2 strain in this study.

• Molecules and Cells
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• v.21 no.1
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• pp.153-160
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• 2006

Virus-induced gene silencing (VIGS) is an attractive reverse-genetics tool for studying gene function in plants. We showed that silencing of a phytoene desaturase (PDS) gene is maintained throughout TRV-PDS-inoculated tomato plants as well as in their flowers and fruit and is enhanced by low temperature ($15^{\circ}C$) and low humidity (30%). RT-PCR analysis of the PDS gene revealed a dramatic reduction in the level of PDS mRNA in leaves, flowers and fruits. Silencing of PDS results in the accumulation of phytoene, the desaturase substrate. In addition, the content of chlorophyll a, chlorophyll b and total chlorophyll in the leaves of PDS-silenced plants was reduced by more than 90%. We also silenced the LeEIN2 gene by infecting seedlings, and this suppressed fruit ripenning. We conclude that this VIGS approach should facilitate large-scale functional analysis of genes involved in the development and ripening of tomato.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.85-91
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• 2001

To find diagnosing method of nitrogen status in tomato plant for determining optimum application rate of side dress, chlorophyll reading values were measured by portable chlorophyll meter(SPAD 502, Minolta), and compared with nitrogen supplying capability of soils. Regression between dry weight, amount of nitrogen uptake, and chlorophyll reading at stalk positions of tomato grown on the condition of no fertilization were evaluated For 6 green house soils with different nitrate concentrations ranged from $55mg\;kg^{-1}$ to $306mg\;kg^{-1}$. The chlorophyll reading of tomato leave was significantly correlated with amount of nitrogen per unit area of leave suggesting that chlorophyll content is useful for nitrogen diagnosis of tomato plant. The chlorophyll reading showed peak at the 15th leaf of stalk position on the 45th days after transplanting and this suggested that below or near the 15th leaf and before or near the 45th days after transplanting is the critical stalk position and time for diagnosing nitrogen status of tomato by chlorophyll test. The chlorophyll reading at the 14th leaf on the 40th days after transplanting was significantly correlated with soil nitrate status, dry weight and amount of nitrogen uptake by tomato grown with no fertilization. From the above correlation, the chlorophyll reading value of 57.1 at the 14th leaf of tomato was estimated as the critical level for maximum dry weight and amount of nitrogen uptake by tomato grown with no fertilization. Consequently, chlorophyll reading of tomato leaves measured by portable chlorophyll meter was thought to be available as a rapid plant test for predicting the nitrogen supplying capability of green house soils.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.563-570
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• 2014

The shortage or surplus of minerals directly affects overall physiological metabolism of plants; especially, it strongly influences carbohydrate metabolism as a primary response. We have studied mineral uptake, synthesis and partitioning of soluble carbohydrates, and the relationship between them in N, P or K-excessive tomato plants, and examined the interaction between soluble carbohydrates and mineral elements. Four-weeks-old tomato plants were grown in a hydroponic growth container adjusted with excessive N ($20.0mmol\;L^{-1}$ $Ca(NO_3)2{\cdot}4H_2O$ and $20.0mmol\;L^{-1}$ $KNO_3$), P ($2.0mmol\;L^{-1}$ $KH_2PO_4$), and K ($20.0mmol\;L^{-1}$ $KNO_3$), respectively, for 30 days. Shoot growth rates were significantly influenced by excessive N or K, but not by excessive P. The concentrations of water soluble N (nitrate and ammonium), P and K were clearly different with each tissue of tomato plants as well as the mineral conditions. The NPK accumulation in all treatments was as follows; fully expanded leaves (48%) > stem (19%) = roots (16%) = petioles (15%) > emerging leaves (1). K-excessive condition extremely contributed to a remarkable increase in the ratio, which ranged from 2.79 to 10.34, and particularly potassium was dominantly accumulated in petioles, stem and roots. Fresh weight-based soluble sugar concentration was the greatest in NPK-sufficient condition ($154.8mg\;g^{-1}$) and followed by K-excessive (141.6), N-excessive (129.2) and P-excessive (127.7); whereas starch was the highest in K-excessive ($167.0mg\;g^{-1}$) and followed by P-excessive (146.1), NPK-sufficient (138.2) and N-excessive (109.7). Soluble sugar showed positive correlation with dry weight-based total N content (p<0.01) whereas was negatively correlated with soluble P (p<0.01) and dry weight-based total P (p<0.01). On the other hand, starch production was negatively influenced by total N (p<0.001), but, it showed positive relation with total K concentration (p<0.05). This study shows that uptake pattern of NPK and production and partitioning of soluble carbohydrate were substantially different from each mineral, and the relationship between water soluble- and dry weight-based-mineral was positive.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.466-470
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• 2010

Food contamination through antibiotic uptake by plants has been one of the major concerns regarding animal manure amendment to agricultural land. Antibiotic uptake by plants was tested with three veterinary antibiotics such as chlortetracycline (CTC), tylosin (TYL), and sulfamethazine (SMT) and three plants such as lettuce, tomato, and hairy vetch. Antibiotic-treated swine slurry was applied to a greenhouse soil before transplanting or sowing the plants. The treated antibiotic concentrations to the swine slurry were 22.9 mg CTC $L^{-1}$, 27.8 mg TYL $L^{-1}$, and 32.4 mg SMT $L^{-1}$. Lettuce was harvested on 64 days after transplanting and 94 days for tomato and hairy vetch. Concentrations of CTC were 3.4 ng $g^{-1}$ for lettuce and 0.7 ng $g^{-1}$ for tomato on a fresh weight basis. For TYL, 20.1 ng $g^{-1}$ from lettuce leaves and 3.0 ng $g^{-1}$ from whole hairy vetch were detected. Sulfamethazine showed greatest concentration among the three antibiotics, 63.3 ng $g^{-1}$ in lettuce leaves, 30.2 ng $g^{-1}$ in tomato fruits, and 20.9 ng $g^{-1}$ in hairy vetch. The results imply that antibiotic uptake by plants may be dependent on antibiotic type and plant type.

• Research in Plant Disease
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• v.15 no.1
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• pp.23-29
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• 2009

Cooking oil and yolk mixture (COY), a environmentally acceptable plant protection agent, and COY+$CaCO_3$+neem oil mixture were studied to control the powdery mildew occurring on eggplant, paprika, cherry tomato and maturity tomato in glass houses and vinyl houses during 2005 to 2007. The morphological changes of the pathogenic fungi on the leaf surface before and after treatment of COY were observed. COY made of rape seed oil and COY+$CaCO_3$+neem oil mixture were sprayed three times with 5 days interval to foliar parts of eggplant, paprika and tomato and the disease development were examined 5 days after final spray. In eggplant, the control efficacy of COY to powdery mildew was 94.6%. In paprika, the control efficacy of COY to powdery mildew was 91.6% and that of COY+$CaCO_3$+neem oil mixture was 96.2% that revealed little higher than COY itself. In tomatoes(cherry or maturity tomato), the control efficacy of COY were about 91 %, however, when COY mixture were sprayed to tomato leaves and stems the powdery mildew was controlled completely. Typical and healthy mycelia, conidiophores and condia were observed through scanning electron microscope in COY unsprayed leaf surface, on the other hand destroyed and winkled mycelia and conidiophores were observed in COY treated leaves regardless host plants nor taxonomic differences of fungi.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.267-272
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• 2011

Several reports indicated that astaxanthin and zeaxanthin have more active anticancer activity than pro-vitamin A carotenes. ${\beta}$-carotene hydroxylase is a key enzyme to synthesize zeaxanthin and astaxanthin in carotenoids biosynthesis pathway. We isolated the ChyB gene encoding ${\beta}$-carotene hydroxylase from tomato leaves. The ChyB gene (1.5Kbp) fragment was cloned into the binary vector and designated to pIG121-ChyB-tom. Agrobacterium-mediated infiltration was used for transient assay in Nicotiana benthamiana. Leaf samples were collected 0, 1, 2, 3 days after infiltration (DAI). RT-PCR result showed that the expression of ${\beta}$-carotene hydroxylase transcripts was not detected in control (0DAI), but its expression was detected after 1 DPI and increased later on. When the activity of ${\beta}$-carotene hydroxylase was measured, the 1,1-diphenyl-pricryl hydrazyl (DPPH) radical scavenging activity (27%) at 2 DAI was significantly higher than that (21%) at 0 DAI. These results indicated that anti-oxidant activity dramatically increased at 2 DAI in tobacco leaves was due to over expression of tomato ${\beta}$-carotene hydroxylase. These results can be the foundation to develop tomato cultivars with high oxy-carotenoids content using the ChyB gene transformation.

• Research in Plant Disease
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• v.27 no.1
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• pp.32-37
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• 2021

In May 2020, necrosis and necrotic ring patterns were observed on leaves of three of 140 Iris domestica plants in a demonstration garden in Wanju, Jeollabuk-do. Three symptomatic plants were found to be infected by tomato spotted wilt virus (TSWV). To analyze the whole genomic sequence of one TSWV isolate, 'Blackberry lily-kr1', L, M, and S genome segments were sequenced and analyzed by comparison of nucleotide sequences of the three segments with corresponding sequences of other TSWV isolates. 'Blackberry lily-kr1' isolate was most closely related to 'JJ' isolate (MF159046) or 'HJ' isolate (LC273305) in the L segment, and to 'JJ' isolate (MF159058 and KY021439) in the M and S segments, respectively. Phylogenetic analysis by Maximum likelihood method using MEGA X program with 'Blackberry lily-kr1' isolate showed high relationship with 'JJ' pepper isolate or 'HJ' Humulus japonicas isolate in the all three segment. Necrosis and double ring patterns on leaves were formed in the glasshouse after inoculation of healthy I. domestica plants with sap of 'Blackberry lily-kr1'-infected Nicotiana rustica plants. This result suggests that I. domestica plants showing necrotic ring patterns in the open field are caused by TSWV infection. This is the first report of TSWV infection of I. domestica in Korea.

• Smart Media Journal
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• v.11 no.5
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• pp.48-55
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• 2022

Tomato crops are easy to expose to disease and spread in a short period of time, so late measures against disease are directly related to production and sales, which can cause damage. Therefore, there is a need for a service that enables early prevention by simply and accurately diagnosing tomato diseases in the field. In this paper, we construct a system that applies a deep learning-based model in which ImageNet transition is learned in advance to classify and serve nine classes of tomatoes for disease and normal cases. We use the input of MobileNet, ResNet, with a deep learning-based CNN structure that builds a lighter neural network using a composite product for the image set of leaves classifying tomato disease and normal from the Plant Village dataset. Through the learning of two proposed models, it is possible to provide fast and convenient services using MobileNet with high accuracy and learning speed.