Nodulation of Aeschynomene afraspera and A. indica by Photosynthetic Bradyrhizobium Sp. Strain ORS285: The Nod-Dependent Versus the Nod-Independent Symbiotic Interaction
Nodulation of Aeschynomene afraspera and A. indica by Photosynthetic Bradyrhizobium Sp. Strain ORS285: The Nod-Dependent Versus the Nod-Independent Symbiotic Interaction
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DOI：
10.1094/mpmi-04-11-0093
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发表时间：
2011-11-01
影响因子：
3.5
通讯作者：
Giraud, Eric
中科院分区：
文献类型：
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作者：
Bonaldi, Katia;Gargani, Daniel;Giraud, Eric
在这里，我们对 Aeschynomene afraspera 和 A. indica 的结瘤过程进行了比较分析，它们对 Nod 因子 (NF) 的需求不同，以启动与光合缓生根瘤菌的共生。使用绿色荧光蛋白标记的慢生根瘤菌（Bradyrhizohium sp.）检查感染过程和结节器官发生。菌株 ORS285 能够使这两种物种结瘤。在籼稻中，当采用不依赖NF的策略时，细菌穿过腋根毛之间的根部细胞间，并通过宿主细胞壁内陷侵入表皮下皮质细胞。虽然第一个被感染的皮质细胞崩溃了，但紧邻其下的被感染的皮质细胞保持了完整性并反复分裂形成结节。在 a. afraspera 中，当使用 NF 依赖性策略时，细菌通过侧根出现所产生的表皮裂隙进入植物，并在根皮层的细胞间更深处扩散，在其进展过程中感染一些皮层细胞。下皮质层的感染细胞迅速分裂形成结节，而上层的感染细胞则产生增生，其中细菌仍然封闭在大的管状结构中。两种不同的感染和根瘤器官发生模式在豆科植物中共存，每种模式都显示出原始特征。
Here, we present a comparative analysis of the nodulation processes of Aeschynomene afraspera and A. indica that differ in their requirement for Nod factors (NF) to initiate symbiosis with photosynthetic bradyrhizobia. The infection process and nodule organogenesis was examined using the green fluorescent protein labeled Bradyrhizohium sp. strain ORS285 able to nodulate both species. In A. indica, when the NF-independent strategy is used, bacteria penetrated the root intercellularly between axillary root hairs and invaded the subepidermal cortical cells by invagination of the host cell wall. Whereas the first infected cortical cells collapsed, the infected ones immediately beneath kept their integrity and divided repeatedly to form the nodule. In A. afraspera, when the NF-dependent strategy is used, bacteria entered the plant through epidermal fissures generated by the emergence of lateral roots and spread deeper intercellularly in the root cortex, infecting some cortical cells during their progression. Whereas the infected cells of the lower cortical layers divided rapidly to form the nodule, the infected cells of the upper layers gave rise to an outgrowth in which the bacteria remained enclosed in large tubular structures. Together, two distinct modes of infection and nodule organogenesis coexist in Aeschynomene legumes, each displaying original features.