Abstract

Organ-specificity of plant defence is an under-represented axis of research in plant biology. However, recent publications point out the importance of this concept in plant–pathogen interactions. Indeed, assuming the resistance status of a whole plant against a given pathogen following studies conducted on a single organ might lead to erroneous conclusions. This study aims at understanding the extent of potato (Solanum tuberosum) organ-specific defence mechanisms after leaf and tuber treatments with pathogen-associated molecular patterns (PAMPs). Our results show that potato leaves and tubers activate contrasting defence responses, in terms of production of reactive oxygen species (ROS) and activation of defence-related genes, following treatments with the Phytophthora PAMP Pep-25 or the bacterial PAMP flg22. Interestingly, flg22 induced ROS production in both leaves and tubers, indicating that this peptide is recognized in these organs. By contrast, ROS production was induced in the leaf but not in the tuber after Pep-25 treatment. Analysis of changes in expression of defence-related genes showed that at least six genes exhibited organ-specific expression patterns. In addition to those early responses, inhibition of potato seedling growth was also found to affect both the aboveground and belowground organs following treatment with Pep-25 and with flg22. Taken together, these experiments will help further the investigation of potato defence against Phytophthora spp.

摘要

植物防御的器官特异性是植物生物学研究中代表性不足的一个轴心。然而，最近的出版物指出了这一概念在植物-病原体相互作用中的重要性。事实上，在对单个器官进行研究之后假设整株植物对给定病原体的抗性状态可能会导致错误的结论。本研究旨在了解用病原体相关分子模式 (PAMPs) 处理叶和块茎后马铃薯 ( Solanum tuberosum ) 器官特异性防御​​机制的程度。我们的研究结果表明，在用疫霉处理后，马铃薯叶和块茎在活性氧 (ROS) 的产生和防御相关基因的激活方面激活了不同的防御反应PAMP Pep-25 或细菌 PAMP flg22。有趣的是，flg22 在叶子和块茎中都诱导了 ROS 的产生，表明这种肽在这些器官中被识别。相比之下，在 Pep-25 处理后，叶中诱导了 ROS 产生，但块茎中没有。对防御相关基因表达变化的分析表明，至少有六个基因表现出器官特异性表达模式。除了这些早期反应外，还发现在用 Pep-25 和 flg22 处理后，抑制马铃薯幼苗生长会影响地上和地下器官。总之，这些实验将有助于进一步研究马铃薯对疫霉属的防御。