Studies On Insect Resistant Gene Transformation Of Betula Platyphylla And The Insect Resistance Of Transgenic Plants

The paper first reported that transgenic plants of Betulla Platyphylla were obtained by Agrobacterium mediated method in China. It replenished the blankness of Birch genetic transformation, and provided a new path for genetic improvement in this species.The materials as explant in transformation come from Birch leaf, stem segment and leaf stalk, and the Spider toxin gene was used as foreign gene for this transformation experiment. It showed that the best explant was the big leaf, on which the transformation frequency was 22%. By GUS detection, there were 43 percent of the plants with kanamycin resistance, and 100 percent of positive result, by PCR amplification, was gotten from random sampling.It indicated that 76.5 percent of positive frequency of all the plants was achieved by using Southern dot hybridization, 87.5 percent of the plants with GUS positive activity was gotten by PCR southern blotting and 42 percent of the plants with GUS positive activity was gotten by southern blotting. It means that insect resistant gene was transferred and integrated into genome of the plants. By northern dot blotting, it also showed that the foreign gene could express in the transgenic plants.The insect feeding test indicated that the development of Lymantria dispar was clearly put off, in which the insects feeded transgenic plants were 2 ages, when the insects as the control were 4 ages after treating 15 days. Besides, the insect growth was restrained, that the weight of insect as control was 9.7 and 6.4 times compared to the treated ones. It also resulted that the foreign gene could normally express in the transgenic plants by displaying insect resistance in a certain degrees. It reached to 30 percent in mortality rate to Lymantria dispar.