National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
The bacteria Photorhabdus associated symbiotically with the entomopathogenic nematodes of genus Heterorhabditis is an effective killer of insect-pests belonging to a different order. The bacteria Photorhabdus encodes numerous toxins once inside the midgut of insects and cause rapid death by employing multiple toxicity mechanism. In this paper, we isolated the bacteria Photorhabdus associated with Heterorhabditis nematodes using a modified White trap and demonstrated a bioassay of toxicity against last instar larva of wax moth Galleria mellonella. The larva was injected with 25µl bacterial suspension inside the midgut by micro syringe at undiluted and diluted concentration. The bacteria was found quick in killing the larva with a medium lethal time 12hr post-injection at both of the concentration. The dead larva turned brick-red upon infestation by bacteria Photorhabdus. The bacteria perform three major tasks once inside the insect body, which includes the production of the digestive enzyme to convert the insect’s tissue into a suitable growth medium. Later bacteria encode multiple toxin protein to kills it hosts and finally release several secondary antibiotic compounds to prevent the growth of any other microbe on the dead cadaver. The full potential of bacteria in crop protection schemes against insect-pests of crops is yet to be realized. The bacteria Photorhabdus have the full potential to be utilized as an alternative of already existing Bt crops once the biological pathways and genes involved in toxicity are understood.
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