Coleopterancidal 6-endotoxin and Constructing Its Genomic Library
抗鞘翅目δ－内毒素 及毒素基因文库的构建

The composition of crytal protein and plasmid patterns, in tive new coleopterancidal strains of Bacillus turingiensis were investigated. Larvae of Plagiodera versicolra was chosen as model insect in assay of toxicity. Strain YM-03 had the highest toxicity. Plasmids patterns were detected, by rapid agarose gel electrophoresis. It was demonstrated that plasmid patterns of five strains were quite different. The partial amino acid sequences for N -terminal of YM-03 crystal protein was analyzed by amino acid analyzer. Genomic library of coleopterancidal S-endotoxin of YM-03 has been constructed. The EcoRI fragements (20-30kDa) of the tatol DNA were ligated with vector DNA of pLAFRI. Thirteen clones which contained both of pLAFRI and foreign DNA fragements out of 17 recombined plasmids were obtained. The frequency of recombinant clones was 76%. Three positive clones, named LE392(pBYM2) , LE392 (pBYM3) and LE392(pBYM4) were detected from 1200 resistant clones by using a synthesized 18bp probe from a coleopterancidal S-endotoxin gene. It was demonstrated that LE392 (pBYM3) and LE392(pBYM4) have the same EcoRI digested pattern,they all contained coleopteran specific S-endotoxin gene but showed a different level of expression.