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Krithika VP, Shandeep G, Bellie A, Gulsar Banu J, Mannu J, Suganthy M, Gomathi V, Uma D, Mohan P. Harnessing nature's arsenal: Ochrobactrum bacteria metabolites in the battle against root- knot nematode - Insights from in vitro and molecular docking studies. J Invertebr Pathol 2024; 204:108114. [PMID: 38636720 DOI: 10.1016/j.jip.2024.108114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/08/2024] [Accepted: 04/15/2024] [Indexed: 04/20/2024]
Abstract
Agricultural Productivity and plant health are threatened by the root-knot nematode. The use of biocontrol agents reduces the need for chemical nematicides and improves the general health of agricultural ecosystems by offering a more environmentally friendly and sustainable method of managing nematode infestations. Plant-parasitic nematodes can be efficiently managed with the use of entomopathogenic nematodes (EPNs), which are widely used biocontrol agents. This study focused on the nematicidal activity of the secondary metabolites present in the bacteria Ochrobactrum sp. identified in the EPN, Heterorhabditisindica against Root-Knot Nematode (Meloidogyne incognita). Its effect on egg hatching and survival of juveniles of root- knot nematode (RKN) was examined. The ethyl acetate component of the cell-free culture (CFC) filtrate of the Ochrobactrum sp. bacteria was tested at four different concentrations (25 %, 50 %, 75 % and 100 %) along with broth and distilled water as control. The bioactive compounds of Ochrobactrum sp. bacteria showed the highest suppression of M. incognita egg hatching (100 %) and juvenile mortality (100 %) at 100 % concentration within 24 h of incubation. In this study, unique metabolite compounds were identified through the Gas Chromatography- Mass Spectrometry (GC-MS) analysis, which were found to have anti- nematicidal activity. In light of this, molecular docking studies were conducted to determine the impact of biomolecules from Ochrobactrum sp. using significant proteins of M. incognita, such as calreticulin, sterol carrier protein 2, flavin-containing monooxygenase, pectate lyase, candidate secreted effector, oesophageal gland cell secretory protein and venom allergen-like protein. The results also showed that the biomolecules from Ochrobactrum sp. had a significant inhibitory effect on the different protein targets of M. incognita. 3-Epimacronine and Heraclenin were found to inhibit most of the chosen target protein. Among the targets, the docking analysis revealed that Heraclenin exhibited the highest binding affinity of -8.6 Kcal/mol with the target flavin- containing monooxygenase. Further, the in vitro evaluation of 3- Epimacronine confirmed their nematicidal activity against M. incognita at different concentrations. In light of this, the present study has raised awareness of the unique biomolecules of the bacterial symbiont Ochrobactrum sp. isolated from H. indica that have nematicidal properties.
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Affiliation(s)
- V P Krithika
- Centre for Agricultural Nanotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
| | - Ganeshan Shandeep
- Department of Nematology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - Anita Bellie
- Department of Nematology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
| | - J Gulsar Banu
- Principal Scientist (Nematology), ICAR-Central Institute for Cotton Research, Coimbatore, Tamil Nadu, India
| | - Jayakanthan Mannu
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - M Suganthy
- Department of Agricultural Entomology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - V Gomathi
- Centre for Agricultural Nanotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - D Uma
- Department of Biochemistry, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore 641003, India
| | - Prasanthrajan Mohan
- Centre for Agricultural Nanotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
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Description of Oscheius cyrus n. sp. (Nematoda: Rhabditidae) as new entomopathogenic nematode from Iran. J Helminthol 2022; 96:e69. [PMID: 36120816 DOI: 10.1017/s0022149x22000529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A new species of the genus Oscheius, Oscheius cyrus n. sp., collected in the moist soils taken from forest heights in the north of Iran, is recorded. A comprehensive description, comprising molecular (internal transcribed spacer (ITS), 18S, and 28S rDNA genes) information, morphometrics data, light microscope and scanning electron microscope images, is supplied. The species resembles Oscheius myriophilus. However, the highest ranges for female body length, female tail, infective juvenile tail length, median bulb, absence of epiptygma and lateral field incisures number vary. The new species was distinguished from Oscheius insectivorus by the general lip region. The male was not found. Molecular analysis showed that the new species has the most similarity to O. myriophilus both in the ITS and 18S regions. Morphological and molecular data confirmed its belonging to the Insectivora-group. Furthermore, the species of Ochrobactrum pseudogrignonense was reported as a dominant associated bacterium of the new Oscheius species. Finally, the mortality of the host after seven days varied from 20% to 82.5%, depending on nematodes' concentration.
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Abstract
A new microbial insecticide mathematical model with density dependent for pest is proposed in this paper. First, the system without impulsive state feedback control is considered. The existence and stability of equilibria are investigated and the properties of equilibria under different conditions are verified by using numerical simulation. Since the system without pulse has two positive equilibria under some additional assumptions, the system is not globally asymptotically stable. Based on the stability analysis of equilibria, limit cycle, outer boundary line and Sotomayor’s theorem, the existence of saddle-node bifurcation and global dynamics of the system are obtained. Second, we consider homoclinic bifurcation of the system with impulsive state feedback control. The existence of order-1 homoclinic orbit of the system is studied. When the impulsive function is slightly disturbed, the homoclinic orbit breaks and bifurcates order-1 periodic solution. The existence and stability of order-1 periodic solution are obtained by means of theory of semi-continuous dynamic system.
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Affiliation(s)
- Tieying Wang
- School of Information and Cyber Security, People’s Public Security University of China, Beijing 100038, P. R. China
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