Host Delivered RNAI Confers Resistance against M. Incognita in Transgenic Tobacco
The phyto-parasitic nematodes are the most harmful pests to crop plants and are responsible for hefty economic loss to the agricultural sector globally. Different approaches employed so far for controlling these dangerous parasites have achieved only partial success or have had some or the other harmful environmental effects. RNAi mediated gene silencing experiments have shown high specificity and efficiency in functional genomic studies carried out for finding out the gene functions. This paper presents an attempt to engineer nematode resistance in the host tobacco plants through HD RNAi (host delivered RNAi). The MiTP gene from Meloidogyne incognita was targeted using HD RNAi strategy. Stable homozygous transgenic tobacco lines (RNAi-MiTP) expressing dsRNAs were generated. The transgenic tobacco lines expressing MiTP gene showed a reduction in the number of knots/plant, number of females/knot, number of egg masses g-1 root wt. and number of eggs g-1 root wt. by 83.6%, 76.9%, 51.6% and 59.5% respectively in comparison to the empty vector control tobacco lines. The RT-PCR done for evaluating the expression of the transgene failed to amplify the MiTP genes from cDNA of the nematodes isolated from the roots of transgenic RNAi-MiTP tobacco lines even after several cycles of amplification. Thus the HD RNAi mediated silencing of MiTP genes in the nematodes resulted in significant and potent resistance in the transgenic tobacco plants against M.incognita and hence it will be highly beneficial in developing nematode resistance the crops.
Keywords - Phyto-Parasitic Nematodes, RNAi, HD RNAi, Transgenic Tobacco Lines, Nematode Resistance.