Characterization of plasmid pAW63, a second self-transmissible plasmid in Bacillus thuringiensis subsp. kurstaki HD73
Characterization of plasmid pAW63, a second self-transmissible plasmid in Bacillus thuringiensis subsp. kurstaki HD73
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DOI：
10.1099/00221287-144-5-1263
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发表时间：
1998-05-01
期刊：
影响因子：
--
通讯作者：
Andrup, L
中科院分区：
文献类型：
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作者：
Wilcks, A;Jayaswal, N;Andrup, L
苏云金芽孢杆菌（Bacillus thuringiensis）亚种kurstaki HD73对鳞翅目幼虫有毒性，含有两个大的自传质粒pHT73和pAW63，长度约为75 kb。结合质粒pHT73已被广泛研究，并被证明含有毒素基因cry1Ac、转座子Tn4430和几个插入序列。本研究表明，次要质粒pAW63也具有自传性，其动员质粒pBC16的效率约为其10-30倍。为了便于pAW63转移的直接选择，用四环素抗性转座子Tn5401标记质粒，在种内交配中发现，2小时后，所有受体都获得了质粒的拷贝。交配实验表明，pAW63可以转移到苏云金芽孢杆菌亚种。以色列芽孢杆菌、蜡样芽孢杆菌、地衣芽孢杆菌、枯草芽孢杆菌和球形芽孢杆菌的共轭函数在这些宿主中均有表达。杂交研究表明，pAW63和pHT73的复制子彼此不同。然而，与转座子Tn4430同源的序列和几个插入序列被证明存在于两个质粒上。
Bacillus thuringiensis subspecies kurstaki HD73, toxic for lepidopteran larvae, contains two large self-transmissible plasmids of approximately 75 kb, pHT73 and pAW63. The conjugative plasmid pHT73 has been studied extensively and has been shown to harbour the toxin gene cry1Ac, the transposon Tn4430 and several insertion sequences. In this study it was demonstrated that the minor plasmid pAW63 is also self-transmissible and about 10-30 times more efficient in mobilizing plasmid pBC16. To facilitate direct selection for pAW63 transfer, the plasmid was tagged with the tetracycline resistance transposon Tn5401 and in intraspecies matings it was found that after 2 h, all recipients had acquired a copy of the plasmid. Mating experiments demonstrated that pAW63 could be transferred to Bacillus thuringiensis subsp. israelensis, Bacillus cereus, Bacillus licheniformis, Bacillus subtilis and Bacillus sphaericus, and that the conjugative functions were expressed in these hosts. Hybridization studies showed that the replicons of pAW63 and pHT73 were distinct from one another. Sequences homologous to transposon Tn4430 and several insertion sequences were, however, shown to reside on both plasmids.