Effect of transgenic tobacco plant, Nicotiana tabacum expressing ribosome inactivating gene isolated from the bulbs of Dutch iris, Iris hollandica on biological parameters of Myzus nicotianae (Hem.: Aphididea) and Spodoptera exigua (Lep.: Noctuidae)

The use of modified crop plants through gene transfer between different plant species plays an important role in pest control programs. We have investigated the insecticidal properties of two lines of tobacco transgenic plant consisting of IRIP (expressed with type 1 ribosome inactivating gene) and IRA (expressed with type 2 ribosome inactivating gene) against beet armyworm, Spodoptera exigua Hübner (Lepidoptera: Noctuidae) and tobacco aphid, Myzus nicotianane Blackman (Hemiptera: Aphididae). The transgenic tobacco plants expressing IRA increased mortality and decreased reproduction rate of tobacco aphid. The reproductive period of tobacco aphid fed on transgenic tobacco plant expressing IRA reduced in comparison with the control and IRIP. We did not observed any impact on reproduction parameters of the aphids treated with IRIP plant in comparison with control. Feeding second instar larvae of S. exigua on transgenic tobacco plant expressing IRA led to about 33.3% mortality. Weight of larvae and pupae as well as the rate of the emergence of adult S. exigua were significantly decreased in larvae fed on IRA in comparison with control. These results suggest that type-2 ribosome inactivating proteins serve as significant insecticidal factors on both insect pest and can be used in integrated pest control programs.