ABSTRACT Cytokinin plays crucial roles in regulating plant growth and development, with the signal transduction mediated by type-A and type-B response regulators (RRs).While much genetic knowledge about RRs on regulating plant height remains unclear. Here, we found that overexpressing an OsORR2 gene (a type-B RR) could reduce plant height in rice compared with the wild type (WT). Using quantitative real time (RT-qPCR) assay, OsORR2was expressed widely in most tissues such as root, culm, sheath, leaf, and panicle. Strong signals were detected in leaf mesophyll cells and anther by in situ hybridization assays (ISH). The subcellular localization of OsORR2 was in cell nucleus. In addition, we found that the transcriptional expression levels of type-A RR genes such as OsRR9, OsRR10, OsRR12, and OsRR13 were significantly up-regulated in the overexpression transgenic plants (OE) plants. Taken together, our data suggested that OsORR2was involved in the development of plant height in rice and provided a foundation for future deep molecular research of the type-B RRs.

中文翻译：

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B型细胞分裂素反应调节剂（OsORR2）的过表达降低了水稻的株高

摘要 细胞分裂素在调节植物生长发育中起着至关重要的作用，其信号转导由 A 型和 B 型反应调节因子 (RRs) 介导。而关于 RRs 调节植物高度的许多遗传知识仍不清楚。在这里，我们发现与野生型 (WT) 相比，过表达 OsORR2 基因（B 型 RR）可以降低水稻的株高。使用实时定量（RT-qPCR）测定，OsORR2在根、茎、鞘、叶和穗等大多数组织中广泛表达。通过原位杂交试验 (ISH) 在叶肉细胞和花药中检测到强信号。OsORR2 的亚细胞定位在细胞核中。此外，我们发现 A 型 RR 基因如 OsRR9、OsRR10、OsRR12、和 OsRR13 在过表达转基因植物 (OE) 植物中显着上调。综上所述，我们的数据表明 OsORR2 参与了水稻株高的发育，并为未来 B 型 RR 的深入分子研究奠定了基础。