Introns of the tobacco resistance gene N play important roles in elicitor-responsive upregulation and efficient induction of defense responses
Introns of the tobacco resistance gene N play important roles in elicitor-responsive upregulation and efficient induction of defense responses
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烟草抗性基因 N 的内含子在诱导子响应上调和有效诱导防御反应中发挥重要作用
DOI：
10.1007/s10327-018-0762-y
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发表时间：
2018
影响因子：
1.2
通讯作者：
H
中科院分区：
文献类型：
--
作者：
Taku;K.;Sasaki;N.;Matsuzawa;K.;Okamura-Mukai;A.;Nyunoya;H
已知烟草抗性基因N在烟草花叶病毒感染或病毒诱导子（称为p50）瞬时表达时转录上调，所述病毒诱导子是病毒复制酶的解旋酶结构域，导致细胞死亡相关的防御反应。为了研究N基因编码的蛋白质和内含子在N基因启动子诱导表达中的作用，我们建立了一个农杆菌介导的瞬时基因转移系统，在缺氮烟草中表达由N基因自身上游区域控制的N转基因。当p50转基因共表达时，带有内含子的N转基因的转录水平显著提高。引入含内含子的N转基因的移码突变废除了其对激发子的反应，但额外表达的功能性N蛋白补充了突变转基因的上调。相比之下，无内含子的N转基因不能被p50共表达上调，导致延迟和减弱的细胞死亡和缓慢诱导防御相关基因表达。此外，在无内含子的N转基因中引入移码突变导致即使与功能性N蛋白共表达也对激发子没有反应。我们的数据提供了第一个证据的重要作用的抗性基因的内含子在激发子响应基因调控和有效的防御诱导。
The tobacco resistance geneNis known to be upregulated transcriptionally upon infection withTobacco mosaic virusor the transient expression of the virus elicitor (termed p50), which is the helicase domain of the virus replicase, leading to cell death-associated defense responses. To investigate the roles of the encoded protein and introns of theNgene in its elicitor-triggered upregulation, we developed anAgrobacterium-mediated transient gene transfer system to express theNtransgene controlled by the upstream region of theNgene itself inN-lacking tobacco. The transcript level of theNtransgene with the introns was enhanced sharply when thep50transgene was coexpressed. Introduction of a frameshift mutation in the intron-containingNtransgene abolished its response to the elicitor, but an additional expression of the functional N protein supplied in trans complemented the upregulation of the mutant transgene. In contrast, an intron-lessNtransgene failed to be upregulated by thep50coexpression, resulting in delayed and attenuated cell death and slow induction of defense-related gene expression. In addition, introduction of a frameshift mutation in the intron-lessNtransgene resulted in no response to the elicitor even with coexpression of the functional N protein. Our data provide the first evidence for important roles of introns of a resistance gene in elicitor-responsive gene regulation and efficient defense induction.