5356
SHEREEN ABDEL HAMEED MOHAMED ABDEL HAMEED
MOLECULAR GENETIC MODIFICATION
OF BACILLUS THURINGENSIS TO
IMPROVE THEIR PERSISTENCE
AS BIOINSECTCIDE
Bacillus thuringiensis, Tuta absoluta, Protoplast fusion, mortality, persistence
Four Bacillus bacterial strains were used in this study. One strain of Bacillus thuringienesis strain (Bt) were used as a cry1Ab donor. The three bacillus strains that naturally colonized on tomato plant were used as recipients; Bacillus subtillus subsp. subtilis strain (Bs1) and Bacillus licheniforms strain (Bl) were used in this study. 16S rDNA sequences, Plasmid pattern and SDS-PAGE protein banding patterns techniques were done on the four Bacillus strains for identification and characterization. Genetic marker test was carried using eleven antibiotics on the previous strains. Three attempts of protoplast fusion technique were done, the first was (Bt::Bs1), the second (Bt::Bl) and the thired was (Bt::Bs2). Eighty seven of fusants products were obtained; 29, 28 and 30 for first, second and third attempts, respectively. Strongest growths of the obtained fusant products of each attempt were chosen for bioassay treatments. Under lab conditions, the obtained results showed as follow; for the first attempt, the best fusion time was 40 min that was registered high mortality percentage of tomato leaf minor ranged from 74 to 100% for fusants product F7, F8 and F9 larval mortality. For second attempt, the accumulative larval mortality were notation the highest percentage reach to 100 in case of treatment by fusant product F19 followed by F20, F13 which gave 87 and 72% larval mortality. For attempt fusant F32 achieved the highest mortality percentage up to 100 percent followed by F33 achieved 72%. Under semi-field conditions, all the chosen fusant products able to tolerate sunray. From the beginning to end of experiments the fusion product F32 showed higher mortality ratio (95.4 and 99.5) than the other new genetic constructed strains; F9 (92 and 98) and F19 (90 and 96), respectively. Field experiment (Long persistence experiment) after two month, infestation percentage were increased to 100% percent (F9 and F32) or close to them (F19). On the contrary, the number of larval tunnels decreased to zero percent (F9 and F32) or close to them (F19).
2017
Ph.d
Ain Shams
Agriculture