Interactions between bacterial diazotrophs and non-legume dicots: Arabidopsis thaliana as a model plant
Interactions between bacterial diazotrophs and non-legume dicots: Arabidopsis thaliana as a model plant
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DOI：
10.1023/a:1004235919993
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发表时间：
1997-07-01
期刊：
影响因子：
4.9
通讯作者：
Denarie, J
中科院分区：
文献类型：
--
作者：
Gough, G;Vasse, J;Denarie, J
当固氮菌和非豆科植物之间的相互作用进行了研究的背景下，试图延长生物固氮非豆科作物，一个重要的第一步是建立可重复的内部定植在这些植物的高频率。使用Azorhizobium caulinodans ORS571（诱导茎和根瘤的热带豆科植物田菁rostrata），与组成型表达的lacZ报告基因标记，我们研究了内部殖民化的模式双子叶植物拟南芥的根系的可能性。发现ORS571能够进入A.在侧根出现的时间点，在第一次定殖侧根裂缝（LRCs）后，拟南芥根。细胞学研究表明，LRC定殖后，细菌进入根的皮层和内胚层细胞层之间的细胞间隙。在我们的实验条件下，这种LRC和细胞间定植是可重复的，并且发生频率很高，尽管每个位点的定植水平很低。发现黄酮类化合物柚皮素和大豆苷元在低浓度下显著刺激（p=0.01水平）LRC和细胞间定殖的频率。thaliana根，A.茎节类研究了结构性的类黄酮ABC基因以及调节基因类黄酮D在定殖中的作用，发现定殖和类黄酮刺激定殖都不依赖于基因。这些系统现在应该使各种遗传和生理因素，限制根瘤菌定植和内生固氮在非豆科植物，进行调查。特别是，使用A.在分子遗传学研究方面，与其他植物相比，拟南芥在研究固氮菌与非豆科双子叶植物之间的相互作用方面具有许多优势，因此，它应提供一种手段，以查明和了解植物基因参与这些相互作用的机制。
When interactions between diazotrophic bacteria and non-legume plants are studied within the context of trying to extend biological nitrogen fixation to non-legume crops, an important first step is to establish reproducible internal colonization at high frequency of these plants. Using Azorhizobium caulinodans ORS571 (which induces stem and root nodules on the tropical legume Sesbania rostrata), tagged with a constitutively expressed lacZ reporter gene, we have studied the possibilities of internal colonization of the root system of the model dicot Arabidopsis thaliana. ORS571 was found to be able to enter A. thaliana roots after first colonizing lateral root cracks (LRCs), at the points of emergence of lateral roots. Cytological studies showed that after LRC colonization, bacteria moved into the intercellular space between the cortical and endodermal cell layers of roots. In our experimental conditions, this LRC and intercellular colonization are reproducible and occur at high frequency, although the level of colonization at each site is low. The flavonoids naringenin and daidzein, at low concentrations, were found to significantly stimulate (at the p=0.01 level) the frequency of LRC and intercellular colonization of A. thaliana roots by A. caulinodans. The role in colonization of the structural nodABC genes, as well as the regulatory gene nodD, was studied and it was found that both colonization and flavonoid stimulation of colonization are nod gene-independent. These systems should now enable the various genetic and physiological factors which are limiting both for rhizobial colonization and for endophytic nitrogen fixation in non-legumes, to be investigated. In particular, the use of A. thaliana, which has many advantages over other plants for molecular genetic studies, to study interactions between diazotrophic bacteria and non-legume dicots, should provide the means of identifying and understanding the mechanisms by which plant genes are involved in these interactions.