title: Effect of gamma radiation on Phenoloxidase pathway, antioxidant defense mechanism in Helicoverpa armigera (Lepidoptera: Noctuidae) and its implication in inherited sterility towards pest suppression.
abstract: OBJECTIVE
  To investigate age-correlated radiosensitivity in highly radioresistant lepidopteran pest, Helicoverpa armigera, upon exposure to ionizing radiation and to examine the irradiation impact on stress-molecular responses in F1 (first-filial) progeny of irradiated (100 Gy) male moths in relation to its reproductive behavior.
  
  
  METHODS
  Efficacy of sub-lethal gamma radiation was evaluated on two markedly apart ontogenic stages, neonates and adult moths. Differential growth, reproductive behavior and stress-indicating molecular responses were examined upto F1 progeny of sub-sterilized moths. Free-radical scavenging enzymes, superoxide dismutase (SOD), catalase (CAT) and Phenoloxidase cascade enzymes, pro-phenoloxidase (PPO), its activating enzyme (PPAE) were studied in irradiated and irradiated plus microbial challenge regimen (dual-stress) by Real-time RT-PCR (reverse-transcription-polymerase-chain-reaction).
  
  
  RESULTS
  An inverse correlation of radiosensitivity with developmental age of insect was observed. F1 sterility was higher than parent sterility. F1 progeny exhibited protraction in development and decreased survival upon irradiation. Sex ratio in F1 progeny was skewed towards males. PPO, PPAE, SOD and CAT transcripts were downregulated upon neonate irradiation resulting in enhanced vulnerability of larvae to incidental microbial challenge. These transcripts were upregulated in F1 progeny of sub-sterilized male moths (100 Gy) upon dual-stress.
  
  
  CONCLUSIONS
  Irradiation impact on stress-indicating molecular responses in F1 progeny is correlated with its reproductive performance. These observations will permit defining regimen having pragmatic viability of 'F1 sterility technique' for pest suppression. Gamma dose of 100 Gy would ensure balance between induced sterility of males and their field competitiveness. These parameters would facilitate integration of biocontrol strategy with parabiological 'Sterile Insect Release Technique'.
authors: International Centre for Genetic Engineering and Biotechnology (ICGEB) , New Delhi.
authors: Bindiya
authors: B
authors: Sachdev
authors: Mahtab
authors: M
authors: Zarin
authors: Zubeda
authors: Z
authors: Khan
authors: Pawan
authors: P
authors: Malhotra
authors: Rakesh Kumar
authors: RK
authors: Seth
authors: Raj K
authors: RK
authors: Bhatnagar
mesh_terms: D000375:Aging / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D007248:Infertility, Male / Q000209:etiology* / Q000235:genetics; D007915:Lepidoptera / Q000502:physiology / Q000528:radiation effects*; D008297:Male; D014442:Monophenol Monooxygenase / Q000378:metabolism / Q000528:radiation effects*; D010572:Pest Control, Biological / Q000379:methods*; D011829:Radiation Dosage; D012098:Reproduction / Q000502:physiology / Q000528:radiation effects; D015398:Signal Transduction / Q000502:physiology / Q000528:radiation effects
chemical_list: D000975:Antioxidants; D014442:Monophenol Monooxygenase