Isolation and characterization of eight bacteriophages infectingErwinia amylovoraand their potential as biological control agents in British Columbia, Canada

As the use of chemical fungicides has raised environmental concerns, biological control agents have attracted interest as an alternative to chemical fungicides for plant-disease control. In this study, we attempted to explore biological control agents for three fungal phytopathogens causing downy mildew, gray mold, and ripe rot in grapevines, which are derived from shoot xylem of grapevines. KOF112, which was isolated from the Japanese indigenous wine grape Vitis sp. cv. Koshu, inhibited mycelial growth of Botrytis cinerea, Colletotrichum gloeosporioides, and Phytophthora infestans. The KOF112-inhibited mycelial tips were swollen or ruptured, suggesting that KOF112 produces antifungal substances. Analysis of the 16S rDNA sequence revealed that KOF112 is a strain of Bacillus velezensis. Comparative genome analysis indicated significant differences in the synthesis of non-ribosomal synthesized antimicrobial peptides and polyketides between KOF112 and the antagonistic B. velezensis FZB42. KOF112 showed biocontrol activities against gray mold caused by B. cinerea, anthracnose by C. gloeosporioides, and downy mildew by Plasmopara viticola. In the KOF112–P. viticola interaction, KOF112 inhibited zoospore release from P. viticola zoosporangia but not zoospore germination. In addition, KOF112 drastically upregulated the expression of genes encoding class IV chitinase and β-1,3-glucanase in grape leaves, suggesting that KOF112 also works as a biotic elicitor in grapevine. Because it is considered that endophytic KOF112 can colonize well in and/or on grapevine, KOF112 may contribute to pest-management strategies in viticulture and potentially reduce the frequency of chemical fungicide application.

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Isolation and Characterization of Photorhabdus Spp. (Enterobacteriaceae) Isolated From Heterorhabditis Bacteriophora in Kashere, Nigeria

Journal of Applied Sciences and Environmental Management ◽

10.4314/jasem.v25i8.9 ◽

2021 ◽

Vol 25 (8) ◽

pp. 1345-1348

Author(s):

H.U. Aliyu ◽

F. Tahir ◽

E.B. Agbo ◽

S.L. Kela

Keyword(s):

Biological Control ◽

Bacterial Isolate ◽

Insect Pests ◽

Entomopathogenic Nematode ◽

Heterorhabditis Bacteriophora ◽

Biochemical Tests ◽

Susceptible Host ◽

Isolation And Characterization ◽

Biological Control Potential

Photorhabdus bacteria are symbiotically associated with the infective juveniles of entomopathogenic nematodes of the genus Heterorhabditis. These bacteria after infecting a susceptible host, produces a host of lethal toxins that killthe insect hosts within 24 to 72 hours. Consequently they have emerged and are trending as excellent biological control agents against insect pests of agricultural crops. Therefore, this study aim to isolate, identify and test the pathogenicity of Photorhabdus bacteria isolated from Heterorhabditis bacteriophora, entomopathogenic nematode from Kashere, Gombe State, Nigeria. To this end phenotypic and biochemical tests were conducted. The tests conducted showed that the isolate exhibited characteristics similar to those of Photorhabdus bacteria that have been identified. Last instar larvae of G. mellonella exposed to different concentrations of the bacterial isolate showed some level of susceptibility of the larvae to the bacterial isolate confirming its biological control potential.

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Partial Characterization of Bacteriophages from Indonesia and its Potency as Biocontrol of Xanthomonas oryzae pv. oryzae

International Journal of Agriculture and Biology ◽

10.17957/ijab/15.1640 ◽

2021 ◽

Vol 25 (01) ◽

pp. 75-80

Author(s):

Desi Rejeki

Keyword(s):

Biological Control ◽

Genome Size ◽

Crop Production ◽

Xanthomonas Oryzae ◽

Biological Control Agents ◽

Vitro Assay ◽

Resistant Varieties ◽

A Genome

Bacterial leaf blight (BLB) is a disease caused by Xanthomonas oryzae pv. oryzae (Xoo) of rice in rice-producing countries including Indonesia and attack rice in all stages of growth. In the advanced, crop production will be decreased by up to 50–70%. Recently, the practical efforts to overcome the problem by using resistant varieties, antibiotics, and sanitation; however, the ability of the pathogen to forms the new virulent pathotypes is noteworthy. Alternatively, the pathogen could be environmental-friendly controlled by utilizing bacteriophages as biological control agents because of their specific characteristics to their bacterial hosts. This research aimed to obtain information about the characteristic of the first isolated bacteriophages from Indonesia. The result showed that two bacteriophages had been isolated from soil in Arjasa Jember and soil in Gadingan Situbondo, namely phage XooX1IDN and phage XooX2IDN, respectively. The two phages were inactivated at 80ºC and stable at pH within the range of 6 to 8. The phage XooX1IDN has a genome size of approximately 39 kb, while phage XooX2IDN had a genome size 38 kb. Morphologically, both phages possessed the family of Myoviridae. Phage biocontrol in vitro assay showed that both phages significantly reduced the growth of BLB pathogen, indicating that both phages potentially, as biological control agents for BLB disease in rice. © 2021 Friends Science Publishers

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Isolation and Characterization of Bacterial Endophytes from Ramie (Boehmeria nivea)

International Journal of Agriculture and Biology ◽

10.17957/ijab/15.1685 ◽

2021 ◽

Vol 25 (02) ◽

pp. 436-440

Keyword(s):

Endophytic Bacteria ◽

Bacillus Pumilus ◽

Bacterial Endophytes ◽

Biological Control Agents ◽

Toxic Compounds ◽

Bacterial Phyla ◽

Boehmeria Nivea ◽

Isolation And Characterization ◽

Rdna Sequencing

Endophytic bacteria provide several advantages to the host plant by promoting growth as well as conferring resistance against pathogens and toxic compounds. More than 90% of the cultivation of ramie [Boehmeria nivea (L.) Gaud] is contributed by China. In our study, 265 isolates of bacterial endophytes were obtained from ramie plants. The isolates were then subjected to PCR-based screening. Four endophytic bacterial phyla were identified using 16S rDNA sequencing. The identified dominant microorganisms were Janibacter melonis, Moraxella, and Bacillus pumilus in the root, stem, and leaf, respectively. The results suggest that these endophytes isolated from the ramie have the potential to act as biocontrol agents against pathogens such as Sclerotinia, Colletotrichum, and Phytophthora. However, further study is required to examine the potential application of bacterial endophytes, particularly as biological control agents. © 2021 Friends Science Publishers

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Isolation and characterization of a high iturin yielding Bacillus velezensis UV mutant with improved antifungal activity

PLoS ONE ◽

10.1371/journal.pone.0234177 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0234177

Author(s):

Young Tae Kim ◽

Sung Eun Kim ◽

Won Jung Lee ◽

Zhao Fumei ◽

Min Sub Cho ◽

...

Keyword(s):

Biological Control ◽

Antifungal Activity ◽

Mutant Strain ◽

Fusarium Wilt ◽

Potential Candidate ◽

Wild Type ◽

Bacillus Velezensis ◽

Sclerotinia Rot ◽

Isolation And Characterization

To isolate Bacillus velezensis mutants with improved antifungal activity for use in the biological control of phytopathogenic fungi, wild-type Bacillus velezensis KRF-001 producing iturin, surfactin, and fengycin was irradiated by ultraviolet (UV) rays. The in vitro and in vivo antifungal activities of UV mutants and characterization of the cyclic lipopeptides produced by a selected mutant were examined. A mutant strain yielding high levels of iturin showed over 2-fold higher antifungal activity than the wild-type against Fusarium oxysporum. A potent suppressive effect of the mutant was also observed on spore germination of Botrytis cinerea, the causative agent of cucumber gray mold, at different butanol extract concentrations. Further analysis of the mutant by real-time PCR and high-performance liquid chromatography revealed increased expression of iturin and surfactin biosynthesis genes as well as enhanced production of iturin and surfactin metabolites. However, the amounts of fengycin obtained from the mutant strain BSM54 were significantly lesser than those of iturin and surfactin. Particularly, iturin A production by the mutant was 3.5-fold higher than that of the wild-type, suggesting that the higher antifungal activity of the mutant against F. oxysporum resulted from the increased expression of biosynthesis genes associated with iturin production. The commercial greenhouse experiment using soil naturally infested with Sclerotinia sclerotiorum (sclerotinia rot) and F. oxysporum (fusarium wilt) showed that the mutant strain reduced sclerotinia rot and fusarium wilt diseases (P = 0.05) more effectively than the wild-type and commercially available product Cillus® in Korea. These results suggest that the mutant with high iturin yield is a potential candidate for the development of a biological control agent in agriculture.

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Diversity and characterization of entomopathogenic fungi from rhizosphere of maize plants as potential biological control agents

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d200536 ◽

2019 ◽

Vol 20 (5) ◽

Cited By ~ 1

Author(s):

NOVRI NELLY ◽

MY SYAHRAWATI ◽

HASMIANDY HAMID ◽

TRIMURTI HABAZAR ◽

DWI NASRI GUSNIA

Keyword(s):

Biological Control ◽

Entomopathogenic Fungi ◽

Maize Plant ◽

Pathogenicity Test ◽

Biological Control Agents ◽

Plant Materials ◽

West Sumatra ◽

Maize Plants ◽

Cultivation Techniques

Abstract. Nelly N, Syahrawati MY, Hamid H, Habazar T, Gusnia DN. 2019. Diversity and characterization of entomopathogenic fungi from rhizosphere of maize plants as potential biological control agents. Biodiversitas 20: 1435-1441. The diversity and characters of entomopathogenic fungi in soil are influenced by cultivation techniques. This study aims at determining the characters and pathogenicity of entomopathogenic fungi in maize plant. Materials were extracted from maize plant rhizosphere at different planting system (monoculture, polyculture, and monoculture of corn on formerly oil palm plantation or replanting) in Nagari Koto Baru, Luhak Nan Duo Subdistrict, West Pasaman District, and West Sumatra Province. Insect bait and series dilution were used to carry out the isolation, while Tenebrio molitor larvae were used for the pathogenicity test. Parameters observed include macroscopic and microscopic characteristics, and pathogenicity of entomopathogenic fungi. The result shows that there are three types of entomopathogenic fungi with various features. After identification, it was known that Aspergillus and Metarizium were obtained from mono, polyculture and by replanting crops, while Beauveria was found from the rhizosphere of corn grown in polyculture with pathogenicity identified as one of the high causes of death to larvae T. molitor with LT50 ranging from 48.03-48.48 hours. Key words: Characterisation, diversity, entomopathogenic fungi, rhizosphere

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