A novel T4SS-mediated DNA transfer used by pXO16, a conjugative plasmid from Bacillus thuringiensis serovar israelensis
A novel T4SS-mediated DNA transfer used by pXO16, a conjugative plasmid from Bacillus thuringiensis serovar israelensis
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DOI：
10.1111/1462-2920.14084
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发表时间：
2018-04-01
影响因子：
5.1
通讯作者：
Mahillon, Jacques
中科院分区：
文献类型：
--
作者：
Makart, Lionel;Gillis, Annika;Mahillon, Jacques
昆虫病原苏云金芽孢杆菌以色列血清型显示出特殊的接合转移能力，大的接合质粒pXO16(350kb)说明了这一点。高效和快速的接合转移伴随着细菌伴侣的宏观聚集。此外，pXO16已被证明能够有效地动员和回溯转移可动员和不可动员的质粒。在这项工作中，聚集现象被证明促进了pXO16的转移，而不是强制性的转移。也观察到将pXO16转移到不显示聚集的苏云金芽孢杆菌受体菌株，从而扩大了先前定义的宿主范围。利用转接子的变种召唤分析，可以观察到高达791kb的染色体区域动员。先前对pXO16的分析没有发现任何IV型分泌系统(T4SS)的同源物，这表明存在一种不寻常的结合系统。FtsK/SpOIIIE ATPase基因是接合转移所必需的。此外，对这两个结合对中的自然限制-修饰系统的分析也归功于单链DNA转移机制。含有该ATPase基因的‘转移以色列质粒’(TIP)区域编码其他潜在的T4SS蛋白，说明了一个与其他已知的革兰氏阳性T4SS蛋白有较远亲缘关系的接合系统。
The entomopathogenic Bacillus thuringiensis serovar israelensis displays peculiar conjugative transfer capabilities, accounted for by the large conjugative plasmid pXO16 (350 kb). The efficient and fast conjugative transfers are accompanied by a macroscopic aggregation of bacterial partners. Moreover, pXO16 has proven capable of effective mobilization and the retro-transfer of both mobilizable and 'non-mobilizable' plasmids. In this work, the aggregation phenomenon is shown to promote pXO16 transfer while not being mandatory for transfer. Transfer of pXO16 to B. thuringiensis recipient strains that do not display aggregation is observed as well, hence enlarging the previously defined host range. The use of variant calling analysis of transconjugants allowed for observation of up to 791 kb chromosomal regions mobilization. Previous analysis of pXO16 did not reveal any Type IV Secretion System (T4SS) homologs, which suggested the presence of an unusual conjugative system. A FtsK/SpOIIIE ATPase gene proved here to be necessary for conjugative transfer. Additionally, the analysis of natural restriction-modification systems in both conjugative partners gave credit to a ssDNA transfer mechanism. A 'transfer israelensis plasmid' (tip) region containing this ATPase gene was shown to code for other potential T4SS proteins, illustrating a conjugative system distantly related to the other known Gram-positive T4SSs.