Endogenous viral sequences and their potential contribution to heritable virus resistance in plants
Endogenous viral sequences and their potential contribution to heritable virus resistance in plants
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DOI：
10.1093/emboj/21.3.461
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发表时间：
2002-02-01
期刊：
影响因子：
11.4
通讯作者：
Matzke, AJM
中科院分区：
文献类型：
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作者：
Mette, MF;Kanno, T;Matzke, AJM
烟草内源性副逆转录病毒（TEPRVs）是在植物中发现的第一个病毒衍生的重复序列家族。teprv的序列保守性和缺乏外源形式的病毒表明，teprv具有有益的功能，可能是通过同源序列相互作用提供病毒抗性。这一假设得到了teprv甲基化和可忽略的转录的观察结果的支持。此外，由TEPRV增强子驱动的转基因在导入烟草时被沉默和甲基化，但在缺乏TEPRV同源序列的非宿主物种中保持活性和未甲基化。在转基因拟南芥中，TEPRV增强子主要在茎分生组织中活跃。这表明产生teprv的病毒可以感染生殖细胞前体，这是减数分裂遗传插入宿主染色体的先决条件。自多倍体形成以来，四倍体烟草及其二倍体祖先烟叶（Nicotiana sylvestris）中teprv的拷贝数、组织和甲基化一直保持不变。在两个独立进化的物种中，这些特征的显著保存进一步支持了teprv在病毒免疫中的作用。
Tobacco endogenous pararetroviruses (TEPRVs) represent the first virus-derived repetitive sequence family found in plants. The sequence conservation of TEPRVs and the lack of an exogenous form of the virus suggest that TEPRVs serve a beneficial function, perhaps by furnishing virus resistance via homologous sequence interactions. This hypothesis is supported by the observation that TEPRVs are methylated and negligibly transcribed. Moreover, transgenes driven by the TEPRV enhancer are silenced and methylated when introduced into tobacco, but remain active and unmethylated in non-host species devoid of sequences homologous to TEPRVs. In transgenic Arabidopsis, the TEPRV enhancer is active primarily in shoot meristems. This suggests that the virus giving rise to TEPRVs could infect germ cell precursors, a prerequisite for meiotically heritable insertions into host chromosomes. The copy number, organization and methylation of TEPRVs in tetraploid tobacco and one of its diploid ancestors, Nicotiana sylvestris, the presumed original host for the virus, have remained constant since polyploid formation. The remarkable conservation of these features in two independently evolving species further supports a role for TEPRVs in viral immunity.