The TIR-NBS but not LRR domains of two novel N-like proteins are functionally competent to induce the elicitor p50-dependent hypersensitive response
The TIR-NBS but not LRR domains of two novel N-like proteins are functionally competent to induce the elicitor p50-dependent hypersensitive response
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DOI：
10.1016/j.pmpp.2007.11.002
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发表时间：
2007-07-01
影响因子：
2.7
通讯作者：
Nyunoya, Hiroshi
中科院分区：
文献类型：
--
作者：
Gao, Jun-Shan;Sasaki, Nobumitsu;Nyunoya, Hiroshi
烟草N蛋白识别烟草花叶病毒（TMV）复制酶的解旋酶结构域（p50）作为激发子并介导过敏反应（HR）。我们从烟草（Nicotiana tabacum cv.）Samsun NN NL-C26和NL-B69具有Toll-白细胞介素-1受体/核苷酸结合位点/富含亮氨酸重复序列（TIR-NBS-LRR）结构，与N的同源性分别为78%和73%。NL-C26和NL-B69基因在N.烟草Samsun nn，缺少N基因。与N不同，当与p50共表达时，NL-C26和NL-B69未能在Samsun nn叶中的农杆菌渗入位点上诱导HR。然而，在Samsun nn中的激发子依赖性HR被具有NL-C26和NL-B69的连续TIR-NBS结构域的嵌合N蛋白有效地诱导。另一方面，HR诱导的效率在具有NL蛋白的TIR和NBS结构域的嵌合N蛋白之间变化显著。因此，NL-C26和NL-B69的TIR-NBS结构域可以在功能上适应N的LRR结构域，这可能决定了对激发子的特异性。我们推测，NL基因是潜在的HR诱导的抗病基因以外的TMV未知病原体。(C)2007年由Elsevier Ltd.出版
The tobacco N protein recognizes the helicase domain (p50) of the Tobacco mosaic virus (TMV) replicase as an elicitor and mediates hypersensitive response (HR). We obtained two cDNA clones encoding novel N-like (NL) proteins NL-C26 and NL-B69 from Nicotiana tabacum cv. Samsun NN. NL-C26 and NL-B69 had a Toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (TIR-NBS-LRR) structure and showed 78% and 73% identities to N, respectively. The NL-C26 and NL-B69 genes were also expressed in N. tabacum cv. Samsun nn, which lacks the N gene. Unlike N, NL-C26 and NL-B69, when coexpressed with p50, failed to induce HR on the sites of agroinfiltration in Samsun nn leaves. However, the elicitor-dependent HR in Samsun nn was induced efficiently by chimeric N proteins with the continuous TIR-NBS domains of NL-C26 and NL-B69. On the other hand, the efficiency of HR induction varied significantly among chimeric N proteins with either of the TIR and NBS domains of the NL proteins. In contrast, chimeras carrying the LRR domains of the NL proteins did not induce HR. Thus, the TIR-NBS domains of NL-C26 and NL-B69 could functionally adapt to the LRR domain of N, which may determine the specificity for the elicitor. We speculate that the NL genes are potential HR-inducing resistance genes for undetermined pathogens other than TMV. (C) 2007 Published by Elsevier Ltd.