Host plants benefit from legume root nodule symbiosis with nitrogen-fixing bacteria under nitrogen-limiting conditions. In this interaction, the hosts must regulate nodule numbers and distribution patterns to control the degree of symbiosis and maintain root growth functions. The host response to symbiotic bacteria occurs discontinuously but repeatedly at the region behind the tip of the growing roots. Here, live-imaging and transcriptome analyses revealed oscillating host gene expression with approximately 6-hour intervals upon bacterial inoculation. Cytokinin response also exhibited a similar oscillation pattern. Cytokinin signaling is crucial to maintaining the periodicity, as observed in cytokinin receptor mutants displaying altered infection foci distribution. This periodic regulation influences the size of the root region responsive to bacteria, as well as the nodulation process progression.

中文翻译：

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百脉根瘤菌感染和根瘤发育中的周期性细胞分裂素反应


在氮限制条件下，寄主植物受益于豆科植物根瘤与固氮细菌的共生。在这种相互作用中，宿主必须调节根瘤数量和分布模式，以控制共生程度并维持根系生长功能。宿主对共生细菌的反应在生长的根尖后面的区域不连续但重复地发生。在这里，实时成像和转录组分析显示，细菌接种后宿主基因表达以大约 6 小时的间隔出现振荡。细胞分裂素反应也表现出类似的振荡模式。细胞分裂素信号传导对于维持周期性至关重要，正如在显示改变的感染灶分布的细胞分裂素受体突变体中观察到的那样。这种周期性调节影响根部区域对细菌反应的大小，以及结瘤过程的进展。