Unité Mixte de Recherches Interactions Biotiques et Santé Végétale, INRA1301-CNRS6243-UNS, 400 route des Chappes, F-06903 Sophia Antipolis, France.
New Phytol. 2010 Jul;187(2):449-460. doi: 10.1111/j.1469-8137.2010.03272.x. Epub 2010 Apr 29.
*The outcome of plant-microbe interactions is determined by a fine-tuned molecular interplay between the two partners. Little is currently known about the molecular dialogue between plant roots and filamentous pathogens. We describe here a new pathosystem for the analysis of molecular mechanisms occurring during the establishment of a compatible interaction between Arabidopsis thaliana roots and a root-infecting oomycete. *We performed cytological and genetic analyses of root infection during the compatible interaction between A. thaliana and Phytophthora parasitica. *Phytophthora parasitica uses appressoria to penetrate A. thaliana roots. Initial biotrophic growth is accompanied by the formation of haustoria, and is followed by a necrotrophic lifestyle. Arabidopsis thaliana mutants with impaired salicylic acid (SA), jasmonic acid (JA) or ethylene (ET) signaling pathways are more susceptible than the wild-type to infection. The salicylate- and jasmonate-dependent signaling pathways are concertedly activated when P. parasitica penetrates the roots, but are downregulated during invasive growth, when ethylene-mediated signaling predominates. *Thus, defense responses in A. thaliana roots are triggered immediately on contact with P. parasitica. Our findings suggest that the pattern of early defense mechanism activation differs between roots and leaves.
植物与微生物的相互作用的结果取决于两者之间精细的分子相互作用。目前对于植物根系和丝状病原体之间的分子对话知之甚少。我们在这里描述了一个新的病理系统，用于分析拟南芥根系与根侵染卵菌之间建立相容相互作用过程中发生的分子机制。我们对拟南芥与寄生疫霉的相容互作过程中的根侵染进行了细胞学和遗传学分析。寄生疫霉利用附着胞穿透拟南芥的根。初始的生物营养生长伴随着吸器的形成，随后是坏死营养生长。与野生型相比，水杨酸（SA）、茉莉酸（JA）或乙烯（ET）信号通路受损的拟南芥突变体更容易被感染。当寄生疫霉穿透根时，水杨酸和茉莉酸依赖的信号通路协同激活，但在侵入性生长时下调，此时乙烯介导的信号通路占主导地位。因此，拟南芥根中的防御反应在与寄生疫霉接触时立即被触发。我们的发现表明，早期防御机制的激活模式在根和叶之间存在差异。
