SCREENING AND EVALUATION OF INSECTICIDAL RNAI PARTIAL GENE CONSTRUCTS IN NON-TARGET INSECT SPECIES

Potato Virus X mediated VIGS mechanism was employed for colossal reproduction of dsRNA in tobacco plants to screen partial gene RNAi constructs of 152bp Calcium channel alpha 1a (CAα1a, 325bp nuclear gene) and Elongation factor-1a (ELF1-a) from cotton mealybug P. solenopsis Tinsley and Arginine kinase (AK) from A. gossypii in non-target insect species. Feeding dsRNA of CAα1a and ELF1-a in aphid species M. persicae Sulzer exhibited no significant insecticidal RNAi effect in terms of adult aphid mortality and nymphs reproduction by adult aphids and non-significant insecticidal effects in terms of larval mortality in H. virscens (p 0.05). Feeding CAα1a showed significant insecticidal effects on larval mortality and larval development in S. litturalis and dry weight gain in H. virescens (p 0.05 and p 0.01, respectively). AK exhibited visible and strong significant insecticidal RNAi effects (p 0.01) in terms of adult aphid mortality, nymphs production and survival of M. persicae ,as well as in term of larval mortality and dry weight gain of survived larvae of S. litturalis and H. virescence on transgenic tobacco plants. The results showed visible clues of some of the non-target RNAi effects which seems to be highly dependent on homology and length of nucleotide sequences utilized closest to taxa in evaluation of nontarget RNAi effects.