Two Entomopathogenic Bacteria, Xenorhabdus nematophila K1 and Photorhabdus temperata subsp. temperata ANU101 Secrete Factors Enhancing Bt Pathogenicity against the Diamondback Moth, Plutella xylostella

Seo, Sam-Yeol; Kim, Yonggyun

doi:10.5656/ksae.2009.48.3.385

Cited by 13 publications

(5 citation statements)

References 24 publications

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“…However, in Africa where food is more important than anything else, organic farming is emerging as alternative agriculture to practice the "Green Revolution in Africa" due to the financial difficulty that keeps farmers from purchasing expensive chemical fertilizers and agricultural pesticide, and thus companion plants are considered suitable for prevention of pests (Hassanali et al, 2008) and are continuously studied in many countries including the U.S. Studies in Korea on eco-friendly pest and weed control using companion plants since 2000 discovered that a greenhouse chrysanthemum farm used Solanum melongena as a trap plant and effectively attracted thrips (Kang et al, 2011). In organic aquaculture of leaf vegetables, Ocimum basilicum, Coriandrum sativum, Houttuynia cordata, Tanacetum cinerariifolium, and Mentha piperita avoided pests (Seo and Kim, 2009), and as a result of using 7 types of Brassicaceae crops such as mustard plants and leaf mustards to attract striped flea beetles, it was found that mustard plants showed the greatest attraction effect (Kim et al, 2013). As such, studies on companion plants as crops promoting plantation diversity and plant growth were mostly focused on controlling diseases and insect pests, while there are relatively insufficient studies on application to and management of urban gardens (Han et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

A Survey on the Perception of Companion Plants for Eco-Friendly Urban Agriculture among Urban Residents

Hong

Yun

Jung

et al. 2021

J. People Plants Environ

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Background and objective: This study was conducted as part of research to promote garden diversity and seek sustainable garden management plans, as well as to determine the trends in understanding and use of companion plants as an eco-friendly farming method and provide the results as the basic data for sustainable urban agriculture. Methods: To determine the trends in garden activities, eco-friendly pest control, and use of companion plants, a survey was conducted on 230 urban residents participating in the Urban Agriculture Expert course. 223 copies of the questionnaire were collected excluding missing values, and IBM SPSS statistics Ver. 25 Program was used for frequency analysis, descriptive statistics, and regression analysis. Results: Most of the respondents were female (71.3%), homemakers (26.5%), were in their 50s (29.1%), and had 2 members in the family (27.8%). 164 respondents (73.5%) had experience in gardening, most of them once a week (31.7%) and for self-consumption (55.5%). Both men and women raised crops for safe food production (32.3%), and they most preferred the city garden type (39.9%). For the preparation of nourishment for eco-friendly garden management, most respondents (60.1%) purchased fertilizers from the market. For the reason why eco-friendly pest control is necessary, all respondents except 4 of them (98.2%) responded that it is necessary 'because it affects my health as I eat it (73.5%)', indicating that they still had a high level of interest in health. Only 43.9% of the respondents said that they had heard of companion plants, 89.2% responded that companion plants were effective in eco-friendly management, and 87.4% showed the will to participate in gardening using companion plants in the future. Finally, the regression analysis confirmed that the awareness of companion plants and satisfaction with gardening activities are key variables that increase the intention to participate in gardening activities in the future. Conclusion: Since plants require special care depending on the period and various diseases and insect pests occur, there must be continuous research on companion plants as an eco-friendly farming method. Moreover, by actively using companion plants in urban gardens with the utility value in not only eco-friendly pest control but also in helping plant growth, urban agriculture is expected to be continuously activated and promoted by increasing satisfaction in gardening activities with aesthetic landscaping and pest control.

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Section: Introductionmentioning

confidence: 99%

A Survey on the Perception of Companion Plants for Eco-Friendly Urban Agriculture among Urban Residents

Hong

Yun

Jung

et al. 2021

J. People Plants Environ

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“…P. temperata subsp. temperata culture broth also possesses immunosuppressive activity that inhibits hemocyte-spreading behavior and nodule formation (33). Moreover, the bacterial culture broth showed a synergistic effect on the pathogenicity of Bacillus thuringiensis (12).…”

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confidence: 97%

Phospholipase A ₂ Inhibitors Synthesized by Two Entomopathogenic Bacteria, Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata

Seo

Lee

Hong

et al. 2012

Appl Environ Microbiol

103

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bThe entomopathogenic bacteria Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata suppress insect immune responses by inhibiting the catalytic activity of phospholipase A 2 (PLA 2 ), which results in preventing biosynthesis of immune-mediating eicosanoids. This study identified PLA 2 inhibitors derived from culture broths of these two bacteria. Both X. nematophila and P. temperata subsp. temperata culture broths possessed significant PLA 2 -inhibitory activities. Fractionation of these bacterial metabolites in the culture broths using organic solvent and subsequent chromatography purified seven potent PLA 2 inhibitors, three of which (benzylideneacetone [BZA], proline-tyrosine [PY], and acetylated phenylalanine-glycine-valine [FGV]) were reported in a previous study. Four other compounds (indole, oxindole, cis-cyclo-PY, and p-hydroxyphenyl propionic acid) were identified and shown to significantly inhibit PLA 2 . X. nematophila culture broth contained these seven compounds, while P. temperata subsp. temperata culture broth contained three compounds (BZA, acetylated FGV, and cis-cyclo-PY). BZA was detected in the largest amount among these PLA 2 compounds in both bacterial culture broths. All seven bacterial metabolites also showed significant inhibitory activities against immune responses, such as phenoloxidase activity and hemocytic nodulation; BZA was the most potent. Finally, this study characterized these seven compounds for their insecticidal activities against the diamondback moth, Plutella xylostella. Even though these compounds showed relatively low toxicities to larvae, they significantly enhanced the pathogenicity of Bacillus thuringiensis. This study reports bacterial-origin PLA 2 inhibitors, which would be applicable for developing novel insecticides. Insect immune responses consist of innate cellular and humoral components (2). Upon pathogen infection, pattern recognition receptors recognize nonself and the recognition signal is transferred by immune mediators to effector tissues, such as hemocytes and fat body (7). Eicosanoids form a chemical group of oxygenated polyunsaturated C 20 fatty acids, which are derived from arachidonic acid, a catalytic product of phospholipase A 2 (PLA 2 ) on phospholipid (PL) substrate (3). Two types of eicosanoids, prostaglandins and leukotrienes, are known to mediate the nonself recognition signals against various insect pathogens, including bacteria, fungi, viruses, and parasitoid eggs in insects (38). Inhibition of PLA 2 prevents eicosanoid biosynthesis and suppresses immune responses in response to microbial pathogens (23, 37).Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata are insect pathogens that are symbiotic to the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis megidis, respectively (1, 13, 25). Infective juvenile-stage nematodes enter target insect hemocoel through natural openings (such as mouth, anus, and spiracles) and then release their symbiotic bacteria from the nematode intestine. The releas...

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“…BZA was more potent in inducing developmental retardation and inhibiting pupal development than the others. A similar tendency was also observed in earlier studies (Park et al ., 2009; Seo & Kim, 2009), in which BZA was also more effective to synergize Bt pathogenicity and to inhibit growth of plant bacterial pathogens. This toxicity variation among these metabolites can be explained by their affinity differences in targeting PLA 2 active sites (see below).…”

Section: Discussionmentioning

confidence: 99%

Three metabolites from an entomopathogenic bacterium, Xenorhabdus nematophila, inhibit larval development of Spodoptera exigua (Lepidoptera: Noctuidae) by inhibiting a digestive enzyme, phospholipase A2

Kim

2010

Insect Science

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An entomopathogenic bacterium, Xenorhabdus nematophila, has been known to induce significant immunosuppression of target insects by inhibiting immune-associated phospholipase A 2 (PLA 2 ), which subsequently shuts down biosynthesis of eicosanoids that are critical in immune mediation in insects. Some metabolites originated from the bacterial culture broth have been identified and include benzylideneacetone, proline-tyrosine and acetylated phenylalanine-glycine-valine, which are known to inhibit enzyme activity of PLA 2 extracted from hemocyte and fat body. This study tested their effects on digestive PLA 2 of the beet armyworm, Spodoptera exigua. Young larvae fed different concentrations of the three metabolites resulted in significant adverse effects on larval development even at doses below 100 μg/mL. In particular, they induced significant reduction in digestive efficiency of ingested food. All three metabolites significantly inhibited catalytic activity of digestive PLA 2 extracted from midgut lumen of the fifth instar larvae at a low micromolar range. These results suggest that the inhibitory activities of the three bacterial metabolites on digestive PLA 2 of S. exigua midgut may explain some of their oral toxic effects.terial metabolites gave significant inhibitory effects on PLA 2 activity in a dose-dependent manner (F = 4 431.87; df = 3,24; P < 0.000 1 for luminal extract and F = 2 295.39; df = 3,24; P < 0.000 1 for cellular extract).

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Two Entomopathogenic Bacteria, Xenorhabdus nematophila K1 and Photorhabdus temperata subsp. temperata ANU101 Secrete Factors Enhancing Bt Pathogenicity against the Diamondback Moth, Plutella xylostella

Cited by 13 publications

References 24 publications

A Survey on the Perception of Companion Plants for Eco-Friendly Urban Agriculture among Urban Residents

A Survey on the Perception of Companion Plants for Eco-Friendly Urban Agriculture among Urban Residents

Phospholipase A ₂ Inhibitors Synthesized by Two Entomopathogenic Bacteria, Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata

Three metabolites from an entomopathogenic bacterium, Xenorhabdus nematophila, inhibit larval development of Spodoptera exigua (Lepidoptera: Noctuidae) by inhibiting a digestive enzyme, phospholipase A2

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Two Entomopathogenic Bacteria, Xenorhabdus nematophila K1 and Photorhabdus temperata subsp. temperata ANU101 Secrete Factors Enhancing Bt Pathogenicity against the Diamondback Moth, Plutella xylostella

Cited by 13 publications

References 24 publications

A Survey on the Perception of Companion Plants for Eco-Friendly Urban Agriculture among Urban Residents

A Survey on the Perception of Companion Plants for Eco-Friendly Urban Agriculture among Urban Residents

Phospholipase A 2 Inhibitors Synthesized by Two Entomopathogenic Bacteria, Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata

Three metabolites from an entomopathogenic bacterium, Xenorhabdus nematophila, inhibit larval development of Spodoptera exigua (Lepidoptera: Noctuidae) by inhibiting a digestive enzyme, phospholipase A2

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Phospholipase A ₂ Inhibitors Synthesized by Two Entomopathogenic Bacteria, Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata