Farinelli L, Malnoë P
Federal Agricultural Research Station of Changins (RAC), Nyon, Switzerland.
Mol Plant Microbe Interact. 1993 May-Jun;6(3):284-92. doi: 10.1094/mpmi-6-284.
We transformed SR1 tobacco with a cDNA fragment of the potato virus Y strain N (PVYN) 605 genome which contained the 3' end of the NIb polymerase gene, the coat protein (CP) coding sequence, and most of the viral 3' untranslated region. Complete resistance to several PVY strains was obtained in plants of the R2 generation. The resistance to PVYN and PVYO strains was maintained when the plants were inoculated dually with the potato potyviruses V or A (PVV or PVA). Only partial resistance to PVYN 605 was observed in plants containing the CP coding sequence in an antisense orientation. Both the "sense" and "antisense" plants accumulated CP transcripts and possessed multiple copies of the transgene. Systemic spread of the virus was studied by grafting experiments. The transgenic PVYN 605 CP was undetectable in healthy plants. This protein accumulated in plants of PVY-susceptible CP-transgenic line 4B5-31 when infected by PVYO, PVA, or PVV, but not in plants of line 4B5-S4, that were resistant to PVY and tolerant to PVA or PVV. To assess the role of the transgenic PVYN 605 CP in protection, we transformed plants with a construct bearing a frame-shift mutation at the beginning of the CP coding sequence, and observed partial protection from PVYN 605. Several hypotheses to explain these resistance mechanisms are discussed.
我们用马铃薯Y病毒N株系（PVYN）605基因组的一个cDNA片段转化了SR1烟草，该片段包含NIb聚合酶基因的3'末端、外壳蛋白（CP）编码序列以及大部分病毒3'非翻译区。在R2代植株中获得了对几种PVY株系的完全抗性。当植株同时接种马铃薯马铃薯Y病毒V或A（PVV或PVA）时，对PVYN和PVYO株系的抗性得以保持。在含有反义方向CP编码序列的植株中，仅观察到对PVYN 605的部分抗性。“正义”和“反义”植株均积累CP转录本并拥有转基因的多个拷贝。通过嫁接实验研究了病毒的系统传播。在健康植株中未检测到转基因PVYN 605 CP。当被PVYO、PVA或PVV感染时，这种蛋白在对PVY敏感的CP转基因株系4B5 - 31的植株中积累，但在对PVY具有抗性且对PVA或PVV具有耐受性的株系4B5 - S4的植株中不积累。为了评估转基因PVYN 605 CP在保护中的作用，我们用一个在CP编码序列起始处带有移码突变的构建体转化植株，并观察到对PVYN 605的部分保护。讨论了几种解释这些抗性机制的假说。
