| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1990: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Bacillus thuringiensis which is well known for the production of parasporal inclusions(crystals)toxic for lepidopterous, dipterous and coleopterous insects plays an important role in the microbial control of pest insects. B. thuringiensis strain AF101, belonging to H-serotype 4a : 4b, was selected as the strain of low toxic to silkworm, but highly toxic to other lepidopterous pest insects. Strain AF101 was revealed to possess a single plasmid(pAF101)which contained crystal gene and the entire genome of temperate phage J7W-I. In this study, the genetic analysis of pAF101 in stain AFIOI was carried out for the purpose of developing the effective tool for the molecular breeding of B. thuringiensis.
The physical map of pAF101 was constracted by digesting restriction enzymes. It was revealed that a part of the genome of temperate phage KK-88 which was also lysogenized phage in AF101 and had different induction system from phage J7W-l was located on pAF101. Furthermore, the induction system of these phages were examined to reveal that 34kdal and 50kdal of cellar proteins were repressor like proteins for J7W-l and KK-88, respectively. The crystal gene was cloned from pAF101- The location on pAF101 was detected to find that the crystal gene region was located between the regions of J7W-l phage genome' and KK-88 phage genome. According to these mentioned above, pAF101 was constrcted by mainly three genetical regions, such as two types of phage genome and crystal gene.
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