Linear DNA plasmids of the perennial ryegrass choke pathogen, Epichloë typhina (Clavicipitaceae)
Linear DNA plasmids of the perennial ryegrass choke pathogen, Epichloë typhina (Clavicipitaceae)
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多年生黑麦草窒息病原体 Epichloëtyphina（麦角藻科）的线性 DNA 质粒
DOI：
10.1007/bf00334781
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发表时间：
1991
期刊：
影响因子：
2.5
通讯作者：
C. Schardl
中科院分区：
文献类型：
--
作者：
K. Mogen;M. Siegel;C. Schardl
摘要斑节杆菌是一种棍棒菌科的子囊菌，系统侵染牧草，引起寄主花序窒息病，与一群互惠共生的草类内生真菌有关。从多年生黑麦草(Lolium Perenne)上分离的伤寒沙门氏菌(E.typhina)的线粒体DNA中，发现了3个大小为7.5、2.1和2.0kb的质粒。酶切鉴定结果表明，所构建的重组质粒Et7.5L、Et2.1L和Et2.0L均为线形双链DNA，其5‘端含有蛋白质(PlDNA)。这些质粒之间几乎没有同源性，并且没有整合到线粒体或核基因组中。从其他草类寄主、变形内生菌或其他棒状菌科分离的伤寒沙门氏菌中未检测到同源质粒。然而，在巴兰西亚和紫皮中也存在其他的质粒。伤寒沙门氏菌的一个质粒Et2.0L的部分序列表明，当UGA被认为编码色氨酸时，它是一个开放阅读框。推测的氨基酸序列在脉孢子菌的两个转录酶区域有超过258个氨基酸的24%的同源性，该转录酶是由毛利和瓦库德两个环质粒编码。同源性包括六个在RNA模板依赖的DNA或RNA聚合酶中保守的片段。
SummaryEpichloë typhina is a clavicipitaceous ascomycete which systemically infects grasses, causes choke disease of host inflorescences, and is related to a group of mutualistic grass endophytes. Three plasmids of 7.5, 2.1 and 2.0 kilobase pairs were found in mitochondrial DNA preparations of an E. typhina isolate from perennial ryegrass (Lolium perenne). Results of nuclease digestion indicated that the plasmids, designated Et7.5L, Et2.1L, and Et2.0L, were linear, double-stranded DNAs with protein linked to their 5′-ends (plDNA). The plasmids shared little or no homology with each other, and were not integrated into the mitochondrial or nuclear genomes. No homologous plasmids were detected in isolates of E. typhina from other grass hosts, anamorphic endophytes, or other Clavicipitaceae. However, other plasmids were present in Balansia obtecta and Claviceps purpurea. A partial sequence of one of the E. typhina plasmids, Et2.0L, indicated an open reading frame when UGA was assumed to encode tryptophan. The inferred amino acid sequence had 24% indentity over 258 amino acids in two regions of the reverse transcriptase encoded by the circular Mauriceville and Varkud plasmids of Neurospora spp. The homologies included six segments conserved in RNA template-dependent DNA or RNA polymerases.