Indian Journal of Entomology
Open Access
SCOPUSWeb of Science
  • Year: 2025
  • Volume: 87
  • Issue: 2

Evaluation and Identification of Novel Insecticidal Toxin Genes from Bacillus thuringiensis (Berliner) Isolates

  • Author:
  • Mahadev Naik1, Basavaraj Kalmath1,*, Lakshmikanth2, Saroja Rao2, Syed Dastager3, Arunkumar Hosamani4, Basavaraj Kadannavar5, Harischandra Naik6
  • Total Page Count: 8
  • Published Online: Sep 25, 2025
  • Page Number: 323 to 330

1Department of Agricultural Entomology, College of Agriculture, Raichur584104, Karnataka, India

2Department of Biochemistry, College of Agriculture, Raichur584104, Karnataka, India

3CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune411008, Maharashtra, India

4AICRP on Biocontrol, MARS, Raichur584104, Karnataka, India

5Department of Agricultural Entomology, College of Agriculture, Gangavathi583227, Karnataka, India

6Pesticide Residue and Food Quality Analysis Laboratory, UAS, Raichur584104, Karnataka, India

*Email: bskalmath@gmail.com (corresponding author)

Online Published on 25 September, 2025.

Abstract

The present study evaluated fifteen Bacillus thuringiensis (Berliner) isolates against second instar larvae of tobacco leaf eating caterpiller Spodoptera litura (F) and Vip genes were identified in the effective isolates. Four NCIM isolates (5111, 5112, 5116 and 5117) were found promising, and their LC50 ranged from 2.5×105 to 3.33×105 ppm and 2.20×105 to 2.85×105 ppm in diet incorporation and surface contamination methods, respectively. The NCIM-5111 isolate exhibited the lowest LC50 of 2.5×105 ppm in diet incorporation and 2.2×105 ppm in the surface contamination method. Surface contamination method revealed more mortality of 6.66 to 10.00% across the NCIM isolates. All the isolates were further used for identification of insecticidal toxin (Vip, Cyt) genes, and it was observed that four NCIM isolates harbour the Vip3Aa1 gene and one viz., NCIM-5112 isolate carries the Vip1/Vip2 gene, which has distinct motifs from the Vip toxins that are currently in use.

Keywords

Vegetative insecticidal protein, Cytolytic protein, Entomopathogenic bacterial isolates, Spodoptera litura, Cellular extract, Bioassay, Vip1 and 2, Surface contamination method, Diet incorporation method, Insecticidal proteins, LC50