Serodiagnosis of onion soft rot bacterium (Erwinia carotovora var. carotovora) from onion seeds

Abstract

Studies on the detection of the seed-borne nature of bacterium revealed that bacterial oozing from seed contains Erwinia carotovora var. carotovora and it was confirmed by biochemical studies. Polyclonal antibodies were raised against unfractionated protein of E. carotovora var. carotovora by immunizing in New Zealand white rabbit. DAS-ELISA was carried out to determine the titre value of antibody against antigen from different genotypes at 405 nm absorbance. The studies on the seed infection by soft rot bacteria revealed that the higher titre value compared to disease-free seed materials. Western blot analysis confirmed the presence of 40 kDa bacterial protein, which was isolated from onion seed.

Keywords:

• Erwinia carotovora var. carotovora
• onion seeds
• polyclonal antibody
• antigens

Acknowledgements

The authors are grateful to Dr Veereragavathatham, Professor and Head, Department of vegetables and seed testing laboratory, for providing the onion genotypes and seeds.