Gao Y L, Song Z B, Li W Z, Jiao F C, Wang R, Huang C J, Li Y P, Wang B W
Yunnan Academy of Tobacco Agricultural Sciences, Key Laboratory of Tobacco Biotechnological Breeding, National Tobacco Genetic Engineering Research Center, Kunming, China.
Zhengzhou Tobacco Research Institute, Zhengzhou, China.
Genet Mol Res. 2016 Dec 19;15(4):gmr-15-04-gmr.15049320. doi: 10.4238/gmr15049320.
Axillary branching is controlled by a very complex mechanism involving various endogenous and environmental factors. Previous studies have shown that Tb1/BRC1 is the point of integration in the network of molecular mechanisms regulating axillary branching in plants. In this study, we cloned the Tb1/BRC1 ortholog, NtBRC1, from Nicotiana tabacum and functionally analyzed its role in the control of axillary branching in tobacco. Overexpression of NtBRC1 resulted in significant retardation of axillary branching, and downregulation of this gene resulted in significant acceleration of axillary branching after decapitation. This indicates a negative role for this gene in the regulation of axillary branching. In-line with previous reports, NtBRC1 was found to be expressed predominantly in axillary buds. Additionally, as expected, expression was decreased 8 h following decapitation, which further confirms its role in the suppression of axillary branching. Furthermore, the expression of NtBRC1 was significantly downregulated by cytokinin, but was not affected by GR24, a synthetic strigolactone. Based on the data collected in the present study, we demonstrate that NtBRC1 negatively regulates axillary branching in tobacco after decapitation and functions downstream of the cytokinin signaling pathway inside axillary buds.
腋芽分枝受涉及多种内源性和环境因素的非常复杂的机制控制。先前的研究表明，Tb1/BRC1是植物中调控腋芽分枝的分子机制网络的整合点。在本研究中，我们从烟草中克隆了Tb1/BRC1的直系同源基因NtBRC1，并对其在烟草腋芽分枝控制中的作用进行了功能分析。NtBRC1的过表达导致腋芽分枝显著延迟，该基因的下调导致打顶后腋芽分枝显著加速。这表明该基因在腋芽分枝调控中起负向作用。与先前的报道一致，发现NtBRC1主要在腋芽中表达。此外，正如预期的那样，打顶8小时后表达下降，这进一步证实了其在抑制腋芽分枝中的作用。此外，NtBRC1的表达受细胞分裂素显著下调，但不受合成独脚金内酯GR24的影响。基于本研究收集的数据，我们证明NtBRC1在打顶后对烟草腋芽分枝起负向调控作用，并在腋芽内细胞分裂素信号通路的下游发挥作用。
