Expression of cryIAb Driven by a Wound Inducible Promoter (MPI) in Tomato to Enhance Resistance to Tuta absoluta

Tomato leafminer (Tuta absoluta) is one of the important pests of tomato in Iran. It causes serve losses to tomato yield between 50 to 100% in the world. The cryIAb gene has been introduced into many plant species, including maize resulting in protection of the maize plants against corn borer larvae. In most studies, constitutive promoters such as CaMV35S were employed for genetic transformation; however the constitutive expression of genes led to changes in plant metabolic pathways due to permanent energy consumption in plants. Since, wound inducible promoter MPI (Maize Protease Inhibitor) posses more efficiency and strength than CaMV35S promoter. Therefore, in the current study, transgenic tomato (cv. Falat) plants harboring cryIAb gene under control of the MPI promoter were developed for the first time. The MPI promoter was isolated from maize and cloned into pPZP122 expression vector replacing the CaMV35S promoter. The cryIAb gene was isolated from pCIB4427 and cloned in pPZP122:MPI:cryIAb and the resulting construct was transformed into Agrobacterium AGL1 strain using In planta approach. Initial selection of the transgenic plants was carried out in media culture containing gentamicin. PCR analysis confirmed the presence of transgene in gentamycin-resistance plants in the first and second generations by rate of 62.5% and 75.58%, respectively. Protein dot blotting using anti-CryIAb polyclonal antibody confirmed the presence of protein in the second generation of transgenic lines. Based on the result of Tuta bioassay, transgenic plants demonstrated an enhanced resistance against Tuta. Thus, the wound inducible promoter MPI can be used in genetic transformation of crop plants if insecticidal protein-encoding genes (such as different types of cry) are used and therefore, it is important to be used when plants asked to express only when are being attacked by insect pests.