Expression of Jaburetox 2-Ec in Potato Encodes Resistance Against Tuta absoluta Meyrick (Lepidoptera: Gelechiidae)

Abstract

The tomato leaf miner Tuta absoluta Meyrick is the most serious pest of potato worldwide. In the present study, we explored an alternate approach to induce resistance in potatoes against T. absoluta by engineering Jaburetox-2Ec, an insecticidal peptide derived from an isoform of urease from Jack bean (Canavalia ensiformis L.). The construct was developed by cloning a PCR-amplified fragment of Jaburetox-2Ec (270 bp) in a pBIN61 vector under the control of a 35S promoter and was named pBIN-JBTX. Furthermore, the recombinant plasmid expressing Jaburetox-2Ec was transformed into potato cv. Lady Olympia using Agrobacterium tumefaciens strain EHA105. The results showed the proper integration of the T-DNA region in primary transformants. Quantitative PCR assays showed the independent transgenic lines had enhanced transcript levels of Jaburetox. The leaf biotoxicity assays were performed by releasing pre-starved 2nd, 3rd, and 4th instar larvae of T. absoluta on transgenic potato plants. As a result, depending on the larval stage, the mortality rate of larvae feeding on transgenic plants ranged from 11 to 33%. Additionally, it was found that larvae feeding on control plants gained more weight than those feeding on transgenic plants. Besides that, deformities in larvae feeding on transgenic plants were also recorded. Overall, the results exhibited the insecticidal activity of Jaburetox 2-Ec against T. absoluta. The transgenic lines can be used as a source of germplasm for an efficient potato breeding programme.