نوع مقاله : مقاله کامل، انگلیسی
نویسندگان
1
Department of Biosciences, Chandigarh University, Mohali, Punjab, 140413, India
2
University Center for Research and Development, Department of Biosciences, Chandigarh University Gharuan, Mohali, Punjab, 140413 India
3
Department of Biosciences, Chandigarh University, Mohali 140413, Punjab, India
10.61186/jesi.45.1.9
چکیده
This study provides molecular and phenotypic characterization of an entomopathogenic nematode-bacterium complex isolated from agricultural soil and nematode efficacy against Helicoverpa armigera. The nematode, identified as Steinernema anantnagense KP_CU, was characterized using ITS rRNA, revealing 100% similarity with the type population of S. anantnagense. Phylogenetic analysis confirmed its conspecificity within a clade including S. kushidai, S. akhursti, and S. populi. Concurrently, the associated bacterium, identified as Xenorhabdus sp. KP_CU, exhibited 100% similarity in its 16S rRNA sequence with Xenorhabdus anantnagensis XENO-2T, suggesting conspecificity. Phenotypic characterization aligned bacterium closely with X. anantnagensis, highlighting typical traits such as rod-shaped, gram-negative cells and absence of bioluminescence. Biochemical tests supported this identification, distinguishing KP_CU from other Xenorhabdus species based on citrate utilization and bioluminescence. Phylogenetic analysis based on 16S rRNA placed Xenorhabdus sp. KP_CU within a monophyletic clade with X. anantnagensis, along with sister relationships to X. japonica and X. vietnamensis. The bacterial strain exhibited larvicidal activity against Galleria mellonella and even at the lowest optical density (OD590 = 0.125) induced over 80% larval mortality within merely 24 h post-injection, emphasizing its elevated virulence. The strain KP_CU could kill wax moth larvae with 38, 16 and 9 IJs at 24, 36 and 48 h, respectively. The nematode isolate KP_CU demonstrated high virulence against H. armigera, with complete mortality achieved within 60 h across all tested inoculum levels. Mortality began at 36 h post-inoculation at 100 IJs/larva and was reached within 24 h at 200 IJs/larva. LD50 values decreased significantly from 38 IJs at 24 h to just 9 IJs at 48 h, indicating potent lethality. Additionally, progeny production showed a dose-dependent increase, though slightly reduced at higher doses, suggesting a trade-off between virulence and reproductive success. These results suggest that S. anantnagense could hold potential as a biocontrol agent for H. armigera in India
کلیدواژهها
موضوعات
عنوان مقاله [English]
Biochemical, Ecological and Molecular Characterization of Xenorhabdus anantnagensis Associated with Steinernema anantnagense from India: Evaluating Nematode Efficacy against Helicoverpa armigera
نویسندگان [English]
-
Krishnapriya Okram
1
-
Aashaq Hussain Bhat
2
-
Ladoi Drema
3
1
Department of Biosciences,
Chandigarh University,
Mohali, Punjab, 140413, India
2
University Center for Research and Development, and Department of Biosciences,
Chandigarh University
Gharuan, Mohali, Punjab, 140413, India
3
Department of Biosciences, Chandigarh University, Mohali 140413, Punjab, India
چکیده [English]
This study provides molecular and phenotypic characterization of an entomopathogenic nematode-bacterium complex isolated from agricultural soil and nematode efficacy against Helicoverpa armigera. The nematode, identified as Steinernema anantnagense KP_CU, was characterized using ITS rRNA, revealing 100% similarity with the type population of S. anantnagense. Phylogenetic analysis confirmed its conspecificity within a clade including S. kushidai, S. akhursti, and S. populi. Concurrently, the associated bacterium, identified as Xenorhabdus sp. KP_CU, exhibited 100% similarity in its 16S rRNA sequence with Xenorhabdus anantnagensis XENO-2T, suggesting conspecificity. Phenotypic characterization aligned bacterium closely with X. anantnagensis, highlighting typical traits such as rod-shaped, gram-negative cells and absence of bioluminescence. Biochemical tests supported this identification, distinguishing KP_CU from other Xenorhabdus species based on citrate utilization and bioluminescence. Phylogenetic analysis based on 16S rRNA placed Xenorhabdus sp. KP_CU within a monophyletic clade with X. anantnagensis, along with sister relationships to X. japonica and X. vietnamensis. The bacterial strain exhibited larvicidal activity against Galleria mellonella and even at the lowest optical density (OD590 = 0.125) induced over 80% larval mortality within merely 24 h post-injection, emphasizing its elevated virulence. The strain KP_CU could kill wax moth larvae with 38, 16 and 9 IJs at 24, 36 and 48 h, respectively. The nematode isolate KP_CU demonstrated high virulence against H. armigera, with complete mortality achieved within 60 h across all tested inoculum levels. Mortality began at 36 h post-inoculation at 100 IJs/larva and was reached within 24 h at 200 IJs/larva. LD50 values decreased significantly from 38 IJs at 24 h to just 9 IJs at 48 h, indicating potent lethality. Additionally, progeny production showed a dose-dependent increase, though slightly reduced at higher doses, suggesting a trade-off between virulence and reproductive success. These results suggest that S. anantnagense could hold potential as a biocontrol agent for H. armigera in India.
کلیدواژهها [English]
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Entomopathogenic nematode
-
biocontrol
-
ITS rRNA
-
phylogenetic analysis
-
Virulence
)