• The Plant Pathology Journal
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• 제15권6호
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• pp.348-350
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• 1999

Gray leaf spot of tomato was observed on tomato plants growing in a middle of a pepper field where pepper plants were badly infected with gray leaf spot. Both Stemphylium solani and S. lycopersici were isolated from the lesion. Both species were highly pathogenic on tomato and pepper. This is the first report in Korea of occurrence of gray leaf spot of tomato caused by Stemphylium solani Weber.

• The Plant Pathology Journal
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• 제30권3호
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• pp.299-303
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• 2014

This study aims to isolate and identify the causal pathogen of tomato bacterial wilt in Egypt. In 2008, tomato plants showing typical symptoms of bacterial wilt disease with no foliar yellowing were observed in Minia, Assiut and Sohag governorates, Egypt. When cut stems of symptomatic plants were submerged in water, whitish ooze was evident and longitudinal sections showed a brown discoloration in the vascular tissues. Bacteria were isolated on triphenyl tetrazolium chloride medium and fifteen isolates shown typical morphological and cultural characteristics were confirmed as Ralstonia solanacearum biovar 2 race 1. Pathogenicity tests showed that all isolates proved to be pathogenic to tomato plants, varied from 52 to 97% wilting. This is the first report of R. solanacearum biovar 2 race 1 causing bacterial wilt in tomato crop in Egypt.

• 한국토양비료학회지
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• 제45권6호
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• pp.1065-1072
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• 2012

Crop productivity decreases globally as a result of salinization. However, salinity impact on greenhouse-grown crops is much higher than on field-grown crops due to the overall concentrations of nutrients in greenhouse soils. Therefore, this study was performed to determine the short-term changes in growth, photosynthesis, and metabolites of tomato plants grown in greenhouse under heavily input of fertilizers evaluated by microbial activity and chemical properties of soils. The soils (< 3, 3.01~6, 6.01~10 and > 10.01 dS $m^{-1}$) from farmer's greenhouse fields having different fertilization practices were used. Results showed that the salt-accumulated soil affected adversely the growth of tomato plants. Tomato plants were seldom to complete their growth against > 10.0 dS $m^{-1}$ level of EC. The assimilation rate of $CO_2$ from the upper fully expanded leaves of tomato plants is reduced under increasing soil EC levels at 14 days, however; it was the highest in moderate or high EC-subjected (3.0 ~ 10.0 dS $m^{-1}$) at 28 days. In our experiment, soluble sugars and starch were sensitive markers for salt stress and thus might assume the status of crops against various salt conditions. Taken together, tomato plants found to have tolerance against moderate soil EC stress. Various EC levels (< 3.0 ~ 10.0 dS $m^{-1}$) led to a slight decrease in organic matter (OM) contents in soils at 28 days. Salinity stress led to higher microbial activity in soils, followed by a decomposition of OM in soils as indicated by the changes in soil chemical properties.

• The Plant Pathology Journal
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• 제19권3호
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• pp.181-183
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• 2003

Corky root symptoms caused by Pyrenochaeta lycopersici were observed on the roots and stem base of tomato plants in Korea. Symptoms on infected plants typically appeared as stunting and generally lacking vigor, and infected plants die back from the foliage tips after fruits have set. Brown lesions appearing with bands around the roots were characteristic symptoms of the disease. The lesions become swollen and cracked along the length of the root with corky appearance. Based on cultural and morphological characteristics, the fungus from the diseased plants was identified as Pyrenochaeta lycopersici. Pycnidia were solitary, globose to subglobose, brown to black, darker around the neck region, and measured 173-215 $\mu\textrm{m}$ in diameter with septate setae up to 102-132$\times$6.5 $\mu\textrm{m}$. Conidia were hyaline, unicellular, and 4.2-4.7$\times$l.5-2.0 $\mu\textrm{m}$ long. Optimum temperature for mycelial growth of the p. lycopersici isolates ranged from $20^{\circ}C$ to $25^{\circ}C$. Fifteen isolates off lycopersici were tested for pathogenicity to susceptible and tolerant cultivars of tomato plants by artificial inoculation. Three isolates of P. lycopersici induced typical corky root discoloration on susceptible tomato cultivars but not on tolerant tomato. This is the Erst report in Korea of tomato corky root disease caused by P. lycopersici.

• Journal of Biosystems Engineering
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• 제33권6호
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• pp.446-452
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• 2008

Machine vision system was used for analyzing leaf color disorders of tomato plants in a greenhouse. From the day when a few leave of tomato plants had started to wither, a series of images were captured by 4 times during 14 days. Among several color image spaces, Saturation frame in HSI color space was adequate to eliminate a background and Hue frame was good to detect infected disease area and tomato fruits. The processed image ($G{\sqcup}b^*$ image) by OR operation between G frame in RGB color space and $b^*$ frame in $La^*b^*$ color space was useful for image segmentation of a plant canopy area. This study calculated a ratio of the infected area to the plant canopy and manually analyzed leaf color disorders through an image segmentation for Hue frame of a tomato plant image. For automatically analyzing plant leave disease, this study selected twenty-seven color patches on the calibration bars as the corresponding to leaf color disorders. These selected color patches could represent 97% of the infected area analyzed by the manual method. Using only ten color patches among twenty-seven ones could represent over 85% of the infected area. This paper showed a proposed machine vision system may be effective for evaluating various leaf color disorders of plants growing in a greenhouse.

• 한국식물병리학회지
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• 제11권4호
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• pp.380-382
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• 1995

Yellow spot or blotch symptoms on the upper surface of leaf, without the production of velvet-like fungi on the lower surface of leaf as in the gray mold of tomato caused by Cladosporium fulvum, were observed in tomato (cv. Seokwang) plants in May, 1995, in a vinyl-house of the experimental plot of Gyeongnam Provincial Rural Development Administration, Chinju, Gyeongnam, Korea. We identified this disease as powdery mildew of tomato caused by Oidiopsis taurica (L v.) Arnaud (=Leveillula taurica), which was new to Korea. Conidia of the fungus were borne on uni- or bi-septated conidiophores which were developed through the stomata of the tomato leaf. The conidia were slender, clavate and variable in size (31~111.6$\times$13.1 ${\mu}{\textrm}{m}$). The fungal conidia isolated from tomato leaves were inoculated to tomato plants, and the occurrence of the same disease was confirmed based on the symptomatology and the morphology of the pathogen reisolated.

• 한국토양비료학회지
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• 제45권1호
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• pp.37-42
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• 2012

Improvement of plant growth by Methylotrophic bacteria can be influenced through alterations in growth modulating enzymes or hormones, especially by decreasing ethylene levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC) deaminase or by production of indole-3-acetic acid (IAA). In this study, the effect of seven strains of Methylobacterium on seedling ethylene emission of tomato and red pepper plants was evaluated under greenhouse condition. Ethylene emission was lowest in Methylobacterium oryzae CBMB20 inoculated tomato plants and CBMB110 inoculated red pepper plants at 47 days after sowing (DAS). However, at 58 DAS all inoculated plants showed almost similar pattern of ethylene emission. Methylobacterium inoculated tomato and red pepper plants showed significantly less ethylene emission compared to control. Our results demonstrated that Methylobacterium spp. inoculation promotes plant growth due to the reduction of ethylene emission and therefore can be potentially used in sustainable agriculture production systems.

• 식물병연구
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• 제7권3호
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• pp.134-139
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• 2001

잿빛곰팡이병균 Botrytis cinerea LVF12 분생포자의 토마토 잎 감염에 미치는 영양원의 영향을 조사하고 병원성을 검정한 결과, 0.1M KH$_2$PO$_4$를 첨가한 20% 토마토 쥬스로 만든 분생포자 부유액이 토마토 잎에서 일정하면서도 높은 발병도를 보여 감염에 효과적인 분생포자 영양원으로 선발하였다. 또한 토마토의 생육 단계별로 병원성을 검정한 결과, 유묘보다 성숙한 식물일수록 발병도가 높았고 하위엽이 상위엽보다 발병도가 높았다. 병징은 감염 초기에 갈색의 소형 점무늬가 잎에 형성되고 병반이 잎자루와 줄기까지 진전되면서 잎이 탈락하거나 줄기 전체가 갈변하여 고사하였다. 감염된 열매는 초기에 암갈색의 원형 병반이 형성되고 점점 진전되면서 열매가 물러 썩었는데, 습도가 높을 때에는 병든 잎, 줄기 및 열매가 잿빛의 균사와 분생포자로 뒤덮혀 자연 발생된 병징과 동일한 특성을 보여 주었다.

• Journal of Microbiology and Biotechnology
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• 제32권5호
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• pp.582-593
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• 2022

Among abiotic stresses in plants, drought and chilling stresses reduce the supply of moisture to plant tissues, inhibit photosynthesis, and severely reduce plant growth and yield. Thus, the application of water stress-tolerant agents can be a useful strategy to maintain plant growth under abiotic stresses. This study assessed the effect of exogenous bio-based 2,3-butanediol (BDO) application on drought and chilling response in tomato and turfgrass, and expression levels of several plant signaling pathway-related gene transcripts. Bio-based 2,3-BDOs were formulated to levo-2,3-BDO 0.9% soluble concentrate (levo 0.9% SL) and meso-2,3-BDO 9% SL (meso 9% SL). Under drought and chilling stress conditions, the application of levo 0.9% SL in creeping bentgrass and meso 9% SL in tomato plants significantly reduced the deleterious effects of abiotic stresses. Interestingly, pretreatment with levo-2,3-BDO in creeping bentgrass and meso-2,3-BDO in tomato plants enhanced JA and SA signaling pathway-related gene transcript expression levels in different ways. In addition, all tomato plants treated with acibenzolar-S-methyl (as a positive control) withered completely under chilling stress, whereas 2,3-BDO-treated tomato plants exhibited excellent cold tolerance. According to our findings, bio-based 2,3-BDO isomers as sustainable water stress-tolerant agents, levo- and meso-2,3-BDOs, could enhance tolerance to drought and/or chilling stresses in various plants through somewhat different molecular activities without any side effects.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1124-1136
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• 2019

Salinity is one of the major abiotic stresses that cause reduction of plant growth and crop productivity. It has been reported that plant growth-promoting bacteria (PGPB) could confer abiotic stress tolerance to plants. In a previous study, we screened bacterial strains capable of enhancing plant health under abiotic stresses and identified these strains based on 16s rRNA sequencing analysis. In this study, we investigated the effects of two selected strains, Bacillus aryabhattai H19-1 and B. mesonae H20-5, on responses of tomato plants against salinity stress. As a result, they alleviated decrease in plant growth and chlorophyll content; only strain H19-1 increased carotenoid content compared to that in untreated plants under salinity stress. Strains H19-1 and H20-5 significantly decreased electrolyte leakage, whereas they increased $Ca^{2+}$ content compared to that in the untreated control. Our results also indicated that H20-5-treated plants accumulated significantly higher levels of proline, abscisic acid (ABA), and antioxidant enzyme activities compared to untreated and H19-1-treated plants during salinity stress. Moreover, strain H20-5 upregulated 9-cisepoxycarotenoid dioxygenase 1 (NCED1) and abscisic acid-response element-binding proteins 1 (AREB1) genes, otherwise strain H19-1 downregulated AREB1 in tomato plants after the salinity challenge. These findings demonstrated that strains H19-1 and H20-5 induced ABA-independent and -dependent salinity tolerance, respectively, in tomato plants, therefore these strains can be used as effective bio-fertilizers for sustainable agriculture.