Adaptation of Helicoverpa armigera (Lepidoptera: Noctuidae) to a proteinase inhibitor expressed in transgenic tobacco

摘要: A giant taro proteinase inhibitor (GTPI) cDNA was expressed in transgenic tobacco using three different gene constructs. The highest expression level obtained ca. 0.3% of total soluble protein when the driven by Arabidopsis rbcS ats1 promoter. Repeated feeding trials with Helicoverpa armigera larvae fed on clonally derived T0 and T1 plants expressing GTPI demonstrated that, relative to those control plants, some growth inhibition (22–40%) occurs, but there no increase larval mortality. Proteinase activities GTPI-expressing or GTPI-containing diet were examined monitor spectrum digestive proteinases midgut. Total activity reduced 13%, GTPI-insensitive increased up 17%. Trypsin inhibited 58%, chymotrypsin elastase 26% 16% respectively. These results point an adaptive mechanism this insect that elevates levels other classes compensate for trypsin dietary inhibitors.