Mechanisms of Action of Bacterial Biological Control Agents

Narayanasamy, P.

doi:10.1007/978-94-007-6380-7_5

Cited by 11 publications

(12 citation statements)

References 391 publications

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“…Antibiosis, the secretion of pathogen-inhibiting substances, is one of several possible disease-suppression mechanisms of bacterial biocontrol agents (bBCA) [14][15][16]. In previous studies, F. defendens was isolated, characterized, and identified as a potential bBCA of phytoplasma, with antibiosis as a possible mode of action [9].…”

Section: Resultsmentioning

confidence: 99%

Antimicrobial Activity of Metabolites Secreted by the Endophytic Bacterium Frateuria defendens

Naama-Amar

Gitman

Shoshana

et al. 2020

Plants

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Candidatus Phytoplasma, the causative agent of yellows disease, inflicts substantial damage on several hundred plant species including perennials and annual plants. The endophytic bacterium Frateuria defendens reduces the symptoms of yellows disease in a number of agricultural crops. One possible mode of action is that the bacterium secretes antimicrobial metabolites. To test this hypothesis, the substances secreted by the endophyte during 10 days of growth in an artificial medium were identified by GC-MS (gas chromatography–mass spectrometry). Synthetic analogues to these substances were then used on periwinkle, a nurse culture plant infected by phytoplasma. Phytoplasma quantities were evaluated by quantitative PCR, and disease symptoms were monitored and recorded. It was found that specific compounds identified by the biochemical analysis caused a significant reduction in both the titer of phytoplasma and the disease symptoms in periwinkle when compared to untreated infected plants. Further research is required to examine the potential of these compounds as an effective treatment against yellows disease.

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Section: Resultsmentioning

confidence: 99%

Antimicrobial Activity of Metabolites Secreted by the Endophytic Bacterium Frateuria defendens

Naama-Amar

Gitman

Shoshana

et al. 2020

Plants

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“…: Jari-jari koloni jamur pada kontrol (mm) Ri : Jari-jari koloni jamur menuju pusat antagonis (mm) (Narayanasamy 2013).…”

Section: Sampel Tanamanunclassified

“…Tanaman pasak bumi sama halnya dengan tanaman lain, bahwa dalam satu tanaman minimal ada satu spesies mikrob endofit yang berasosiasi (Miller et al 2012, Alvin et al 2014, Das et al 2017 Pengendalian jamur patogen pada tanaman menggunakan agen hayati bakteri dapat terjadi melalui beberapa mekanisme, antara lain produksi senyawa toksik (enzim hidrolisis, antibiotik, senyawa organik volatil), kompetisi tempat tumbuh dan nutrien, mencegah kolonisasi patogen pada tanaman, dan menginduksi resistensi tanaman (Narayanasamy 2013). Enzim dapat ditemukan pada setiap makhluk hidup, tak terkecuali mikrob.…”

Section: Hasil Dan Pembahasanunclassified

BAKTERI ENDOFIT YANG DIISOLASI DARI AKAR <em>Eurycoma longifolia</em> DAN POTENSINYA SEBAGAI PENGENDALI JAMUR PATOGEN TANAMAN

Sulistiyani

Meliah

Damayanti

2020

J Bioteknol Biosains Indones

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Eurycoma longifoliaÂ (pasak bumi) is known as a medicinal plant that containsÂ biologically active compounds. Studies on endophytic bacteria associated with pasak bumi andÂ theirÂ biocontrol activitiesÂ have not been widely reported.Â The objective of this study is to isolate potential endophytic bacteria associated with E. longifolia possessing biocontrol activity against plant pathogenic fungi, Sclerotium rolfsii, Fusarium solani, F. oxysporum,Â andÂ Colletotrichum gloeosporioides.Â Endophytic bacteria were isolated from the roots of E. longifolia using the plant piece methodÂ and identifiedÂ based on 16S rRNA genes analysis.Â Antagonist test of bacterial isolates was conductedÂ byÂ dual confrontation method.Â TheÂ mechanisms of fungal growth inhibition were evaluated based on their ability to produce hydrolytic enzymes, antibiotic,Â and volatile organic compounds. Two isolates were obtained and identified as Stenotrophomonas maltophilia (Apb1) and Serratia marcescens (Apb2). Apb2 was able toÂ inhibitÂ the growth ofÂ four tested fungi andÂ showed protease, chitinaseÂ as well asÂ cellulase activities. The crude extract and volatile organic compound produced by Apb2Â wereÂ active against F.Â solaniÂ growth.Keywords: biocontrol, endophytic, Eurycoma longifolia, fungi, inhibition mechanismÂ ABSTRAKEurycoma longifoliaÂ (pasak bumi) dikenal sebagai tanaman obat yang mengandungÂ beberapa senyawa aktif secara biologis. PenelitianÂ mengenaiÂ bakteri endofit yang berasosiasi dengan tanaman pasak bumi berikut aktivitasÂ biokontrolnya belumÂ banyakÂ dilaporkan.Â Penelitian ini bertujuan mengisolasi bakteri endofit potensial dari tanamanÂ E. longifoliaÂ yang memiliki aktivitas biokontrol terhadap empat strain uji jamur patogen tanaman, yaitu Sclerotium rolfsii, Fusarium solani, F. oxysporum, dan Colletotrichum gloeosporioides. Bakteri endofit diisolasi dari akarÂ E. longifolaÂ menggunakan metodeÂ plant piece dan diidentifikasi berdasarkan analisis gen 16S rRNA.Â Uji antagonis isolat bakteriÂ dilakukan dengan metode konfrontasi ganda.Â Mekanisme penghambatan jamur patogen tanaman dievaluasi berdasarkan kemampuannya dalam memproduksi enzim hidrolisis, senyawa antibiotik, dan senyawa organik volatil.Â Dua isolat bakteri endofit berhasil diperoleh dan teridentifikasi sebagaiÂ Stenotrophomonas maltophilia Â (Apb1) dan Serratia marcescens (Apb2). Isolat Apb2 mampu menghambat pertumbuhan keempat jamur yang diujiÂ dan menunjukkan aktivitas protease, kitinase dan selulase. Ekstrak kasar dan senyawa organik volatil yang dihasilkan oleh isolat Apb2 aktif menghambatÂ pertumbuhanÂ F. solani.

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“…The search for agricultural-aiding microorganisms is an emerging strategy to tackle many plant pathogens (Hallmann et al, 1997;Compant et al, 2005;Rosenblueth and Martínez-Romero, 2006; Ryan et al, 2008;Narayanasamy, 2013). It is also a more 3 environment-friendly approach compared to the usage of pesticides in agriculture, as researchers have demonstrated the existence of residual chemicals in agricultural crops, which thereby affect the whole food chain (Ekström et al, 2011;Maheshwari et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

An endophytic bacteria (Pseudomonas aeruginosa) strain translocated and protected tomato (Solanum lycopersicum L.) plants from its parasitic weed Phelipanche aegyptiaca

Iasur-Kruh

Nassar

Lidor

et al. 2019

Preprint

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Phelipanche aegyptiaca is an obligate holo-parasitic weed lacking a functional photosynthetic system, which subsists on roots of a wide range of host crops, causing severe losses in yield quality and quantity. The parasite and its host are connected through their vascular system, forming a unique ecological system that enables the exchange of various substances. In a previous study, it was suggested that endophytic bacteria, which naturally inhabit the internal tissues of plants, can also be transmitted from the parasitic weed to its host and vice versa.In the current study, we investigate the characteristics of a previously isolated Pseudomonas sp. PhelS10 strain, using both biochemical and molecular methods. Our results revealed that production of Pseudomonas aeruginosa quinolone signal (PQS) was 2.1 times higher than that of the standard Pseudomonas aeruginosa strain (PAO1), which contributed to a 22% higher biofilm formation capability. PhelS10 strain was detected in the xylem of tomato plants using FISH analysis. In addition, PhelS10 strain was found in the parasitic weed's inner tissues, confirming the hypothesis that endophytic bacteria traffic between the plant host and its parasitic weed.

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Mechanisms of Action of Bacterial Biological Control Agents

Cited by 11 publications

References 391 publications

Antimicrobial Activity of Metabolites Secreted by the Endophytic Bacterium Frateuria defendens

Antimicrobial Activity of Metabolites Secreted by the Endophytic Bacterium Frateuria defendens

BAKTERI ENDOFIT YANG DIISOLASI DARI AKAR <em>Eurycoma longifolia</em> DAN POTENSINYA SEBAGAI PENGENDALI JAMUR PATOGEN TANAMAN

An endophytic bacteria (Pseudomonas aeruginosa) strain translocated and protected tomato (Solanum lycopersicum L.) plants from its parasitic weed Phelipanche aegyptiaca

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