González-Sama Alfonso, Lucas M Mercedes, De Felipe María R, Pueyo José J
Department of Plant Physiology and Biochemistry, Centro de Ciencias Medioambientales, CSIC, Serrano 115-bis, E-28006 Madrid, Spain.
New Phytol. 2004 Aug;163(2):371-380. doi: 10.1111/j.1469-8137.2004.01121.x.
• The infection of white lupin (Lupinus albus) roots and the early stages in organogenesis of the lupinoid nodule are characterized in detail in this work. • Immunolabelling of Bradyrhizobium sp. (Lupinus) ISLU16 and green fluorescent protein labelling of Mesorhizobium loti NZP2037, two strains that induce nodulation in L. albus, allowed us to monitor the infection and morphogenesis process. Light and transmission electron microscopy, low-temperature scanning electron microscopy, fluorescence and confocal microscopy were employed. • Rhizobia penetrated the root intercellularly at the junction between the root hair base and an adjacent epidermal cell. Bacteria invaded the subepidermal cortical cell immediately beneath the root hair through structurally altered cell wall regions. The newly infected cell divided repeatedly to form the central infected zone of the young nodule. Bacteria seemed to be equally distributed between the daughter cells. • A new mode of direct epidermal infection and an unusual morphogenesis for indeterminate nodules lead to the formation of the lupinoid nodule with unique characteristics.
• 本研究详细描述了白羽扇豆（Lupinus albus）根的感染以及羽扇豆类根瘤器官发生的早期阶段。• 对两种能在白羽扇豆中诱导结瘤的菌株，即慢生根瘤菌属（Lupinus）ISLU16和百脉根中生根瘤菌NZP2037进行免疫标记和绿色荧光蛋白标记，使我们能够监测感染和形态发生过程。使用了光学显微镜、透射电子显微镜、低温扫描电子显微镜、荧光显微镜和共聚焦显微镜。• 根瘤菌在根毛基部与相邻表皮细胞的交界处通过细胞间隙穿透根部。细菌通过结构改变的细胞壁区域侵入根毛下方紧邻的表皮下皮层细胞。新感染的细胞反复分裂，形成幼根瘤的中央感染区。细菌似乎在子细胞之间均匀分布。• 一种直接的表皮感染新模式和不定根瘤不寻常的形态发生导致了具有独特特征的羽扇豆类根瘤的形成。
