Dynamics of Responses in Compatible Potato - Potato virus Y Interaction Are Modulated by Salicylic Acid

To investigate the dynamics of the potato – Potato virus Y (PVY) compatible interaction in relation to salicylic acid - controlled pathways we performed experiments using non-transgenic potato cv. Désirée, transgenic NahG-Désirée, cv. Igor and PVYNTN, the most aggressive strain of PVY. The importance of salicylic acid in viral multiplication and symptom development was confirmed by pronounced symptom development in NahG-Désirée, depleted in salicylic acid, and reversion of the effect after spraying with 2,6-dichloroisonicotinic acid (a salicylic acid - analogue). We have employed quantitative PCR for monitoring virus multiplication, as well as plant responses through expression of selected marker genes of photosynthetic activity, carbohydrate metabolism and the defence response. Viral multiplication was the slowest in inoculated potato of cv. Désirée, the only asymptomatic genotype in the study. The intensity of defence-related gene expression was much stronger in both sensitive genotypes (NahG-Désirée and cv. Igor) at the site of inoculation than in asymptomatic plants (cv. Désirée). Photosynthesis and carbohydrate metabolism gene expression differed between the symptomatic and asymptomatic phenotypes. The differential gene expression pattern of the two sensitive genotypes indicates that the outcome of the interaction does not rely simply on one regulatory component, but similar phenotypical features can result from distinct responses at the molecular level.为探究马铃薯与Y病毒（Potato virus Y, PVY）的亲和互作动态及其与水杨酸（salicylic acid）调控通路的关联，本研究采用非转基因马铃薯品种Désirée、转NahG基因的Désirée（NahG-Désirée）、品种Igor以及PVY致病力最强的毒株PVYNTN开展实验。通过水杨酸缺失型材料NahG-Désirée出现显著症状，以及经2,6-二氯异烟酸（2,6-dichloroisonicotinic acid，一种水杨酸类似物）喷施后症状得到逆转，证实了水杨酸在病毒增殖与病害症状形成过程中的关键作用。本研究采用定量PCR（quantitative PCR）技术监测病毒增殖情况，并通过检测选定的光合活性、碳水化合物代谢及防御响应相关标记基因的表达水平，分析植物的响应模式。在本研究所有接种处理的材料中，品种Désirée（本研究中唯一无症状的基因型）的病毒增殖速率最慢。在接种位点处，两个感病基因型（NahG-Désirée与品种Igor）的防御相关基因表达强度显著高于无症状植株（品种Désirée）。感病与无症状表型的植株间，光合及碳水化合物代谢相关基因的表达模式存在显著差异。两个感病基因型的差异基因表达模式表明，该互作的结局并非仅依赖单一调控组分，即便分子层面的响应机制存在差异，也可产生相似的表型特征。