Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IFRMP 23, Plate-forme de Recherche en Imagerie Cellulaire de Haute Normandie, Université de Rouen, 76821 Mont Saint Aignan, France.
Ann Bot. 2011 Sep;108(3):459-69. doi: 10.1093/aob/mcr177. Epub 2011 Aug 1.
The oomycete Aphanomyces euteiches causes up to 80 % crop loss in pea (Pisum sativum). Aphanomyces euteiches invades the root system leading to a complete arrest of root growth and ultimately to plant death. To date, disease control measures are limited to crop rotation and no resistant pea lines are available. The present study aims to get a deeper understanding of the early oomycete-plant interaction at the tissue and cellular levels.
Here, the process of root infection by A. euteiches on pea is investigated using flow cytometry and microscopic techniques. Dynamic changes in secondary metabolism are analysed with high-performance liquid chromatography with diode-array detection.
Root infection is initiated in the elongation zone but not in the root cap and border cells. Border-cell production is significantly enhanced in response to root inoculation with changes in their size and morphology. The stimulatory effect of A. euteiches on border-cell production is dependent on the number of oospores inoculated. Interestingly, border cells respond to pathogen challenge by increasing the synthesis of the phytoalexin pisatin.
Distinctive responses to A. euteiches inoculation occur at the root tissue level. The findings suggest that root border cells in pea are involved in local defence of the root tip against A. euteiches. Root border cells constitute a convenient quantitative model to measure the molecular and cellular basis of plant-microbe interactions.
卵菌纲的腐霉属真菌 Aphanomyces euteiches 可导致豌豆（Pisum sativum）减产 80%。Aphanomyces euteiches 会侵袭根系，导致根系生长完全停止，最终导致植物死亡。迄今为止，疾病控制措施仅限于轮作，尚无抗豌豆品系。本研究旨在更深入地了解卵菌与植物在组织和细胞水平上的早期相互作用。
本研究采用流式细胞术和显微镜技术，研究了 A. euteiches 对豌豆根系的感染过程。利用二极管阵列检测高效液相色谱法分析了次生代谢物的动态变化。
感染始于伸长区，但根冠和边缘细胞不受感染。根接种后，边缘细胞的产量显著增加，其大小和形态发生变化。A. euteiches 对边缘细胞产生的刺激作用取决于接种的卵孢子数量。有趣的是，边缘细胞通过增加植物抗毒素豌豆素的合成来响应病原体的挑战。
在根组织水平上对 A. euteiches 接种有明显的反应。这些发现表明，豌豆的根边缘细胞参与了根尖对 A. euteiches 的局部防御。根边缘细胞构成了一种衡量植物-微生物相互作用的分子和细胞基础的便利定量模型。
