青蒿植物内生链霉菌中的质粒pCQ4与噬菌体ΦCQ4  

Plasmid pCQ4 and its phage ФCQ4 of endophytic Streptomyces sp. from Artemisia annua L.

作　　者：成秋香[1] 钟莉[1] 覃重军[1] 

机构地区：[1]中国科学院上海生命科学研究院植物生理生态研究所合成生物学重点实验室,上海200032

出　　处：《微生物学报》2012年第7期825-831,共7页Acta Microbiologica Sinica

基　　金：国家"973项目"(2011CBA00801);国家自然科学基金(31121001);中国科学院知识创新工程项目(KSCX2-EW-G-13)~~

摘　　要：【目的】在青蒿植物的内生链霉菌W75中检测到一个大的环型质粒pCQ4。克隆、测序、分析和功能研究pCQ4。【方法】Southern杂交确定质粒的酶切图谱,利用接合转移和同源重组方法将质粒克隆到了大肠杆菌BAC衍生的载体上,并进行鸟枪测序和分析。【结果】获得了全长为84833 bp的pCQ4序列,预测编码129个基因,其中成簇的40个基因与其它噬菌体的基因同源。实验证明含有质粒pCQ4的菌株能够低频率释放噬菌体ФCQ4,并可以侵染消除了pCQ4的W75X孢子和形成噬菌斑。在透射电镜下观察到噬菌体颗粒,脉冲场凝胶电泳显示ФCQ4为线型DNA。pCQ4与已发表的链霉菌质粒-噬菌体pZL12比对,编码噬菌体的主要结构蛋白的基因是相似的。【结论】链霉菌大的质粒pCQ4也可以转化为噬菌体ФCQ4,其噬菌体相关的基因簇可能是可转移的单元。[ Objective] Large plasmid pCQ4 was detected in Streptomyces sp. W75 from Artemisia annua L. We clonined, sequenced, analyzed and characterized pCQ4. [ Methods] Southern hybridization was used to determine restriction map of pCQ4. To clone the full-length of pCQ4, conjugation and recombinational cloning in a BAC vector were used. [Results] The complete nucleotide sequence of pCQ4 consisted of 84833-bp, encoding 129 ORFs which 40 ORFs resembled these of bacterial phages. W75 culture could infect W75 cured of pCQ4 and formed plaques on plate. Phage particle （~CQ4） was observed by transmission electron microscopy. Linearq）CQ4 DNA was detected on pulsed-field gel electrophoresis. Comparison to Streptomyces plasmid-phage pZL12, genes encoding major phage structural proteins resembled that of pCQ4. [ Conclusion] Streptomyces plasmid pCQ4 could be transformed into lytic phageФCQ4, and the phage segment on pCQ4 might be a mobile unit.

关 键 词：链霉菌 质粒 噬菌体 

分 类 号：Q93[生物学—微生物学]