Audy P, Palukaitis P, Slack S A, Zaitlin M
Department of Plant Pathology, Cornell University, Ithaca, NY 14853.
Mol Plant Microbe Interact. 1994 Jan-Feb;7(1):15-22. doi: 10.1094/mpmi-7-0015.
Nicotiana tabacum 'Turkish Samsun NN' plants were transformed with nuclear inclusion b (NIb) gene sequences of potato virus Y, O strain (PVYO). The full-length construct included an additional in-frame initiation codon contiguous to the putative N-terminal amino acid codon and a stop codon replacing the C-terminal amino acid codon. Of 13 independently transformed lines, four yielded 37 (out of 100) plants in the R1 generation that were resistant to PVYO infection. Progeny of 13 out of 15 of R1 plants tested expressed resistance in the R2 generation. Conversely, 30 independently transformed tobacco lines expressing essentially the same sequence but deleted for the Gly-Asp-Asp (GDD) motif were not resistant. Two other constructs encoding either the 5'-deleted or 3'-truncated NIb gene, but harboring the GDD motif, conferred resistance to PVYO in some tobacco plants. Despite the high level of nucleotide and amino acid identity shared by strains PVYO and PVYN for the NIb gene, PVYN replication was found in all PVYO-resistant plants. However, plants of one R2 line showed reduced PVYN replication.
用马铃薯Y病毒O株系（PVYO）的核内含体b（NIb）基因序列转化烟草品种“土耳其萨姆松NN”。全长构建体在推定的N端氨基酸密码子旁包含一个额外的框内起始密码子，并替换C端氨基酸密码子的终止密码子。在13个独立转化的株系中，有4个在R1代产生了100株中有37株对PVYO感染具有抗性的植株。15株R1代植株中的13株的后代在R2代表现出抗性。相反，30个独立转化的烟草株系表达基本相同的序列，但缺失了甘氨酸-天冬氨酸-天冬氨酸（GDD）基序，它们没有抗性。另外两个构建体分别编码5'端缺失或3'端截短的NIb基因，但含有GDD基序，在一些烟草植株中赋予了对PVYO的抗性。尽管PVYO和PVYN株系在NIb基因上具有高度的核苷酸和氨基酸同一性，但在所有对PVYO具有抗性的植株中都发现了PVYN的复制。然而，一个R2株系的植株显示出PVYN复制减少。
