Abstract:

Light is one of the most important external environmental factors that affects plant branching， however， whether ELONGATED HYPOCOTYL5 （HY5） regulating plant branching is still unknown. In this study， HY5 transgenic overexpression plants were created and commercial T-DNA insertion mutant homozygous plants were obtained. By comparing the number of branches of wild type （WT）， overexpression plant （HY5-OE） and mutant （hy5?215）， the results showed that the overexpression plants had much more rosette branches， while the mutants had less branches compared with wild type plants. The transcriptional levels of BRC1 （BRANCHED1）， a key negative regulatory factor of Arabidopsis thaliana branches were further compared. The results also showed that BRC1 transcription was significantly down-regulated in overexpressed plants and up-regulated in mutants. The results suggested that HY5 promotes Arabidopsis thaliana branching by inhibiting the transcription of BRC1. These results of this research provided a theoretical basis for elucidating the biological functions of HY5 regulatory branches.

Key words: Arabidopsis thaliana, ELONGATED HYPOCOTYL5, branching

摘要：

光是影响植物分枝的重要外在环境因素，但光信号因子HY5（ELONGATED HYPOCOTYL5）是否调控植物分枝目前尚不清楚。创制了HY5转基因超表达植株，并获得商业化T-DNA插入突变体纯合植株。通过比较野生型（WT）、超表达植株（HY5-OE）、突变体（hy5-215）的分枝数目发现，与野生型相比，超表达植株分枝数目显著增加，而突变体分枝数目则显著减少。进一步比较这些遗传材料的拟南芥植株分枝的负调控关键因子BRC1（BRANCHED1）转录本水平差异，发现与野生型相比，超表达植株中BRC1转录本显著下调、突变体中显著上调。研究结果表明，HY5通过抑制拟南芥分枝关键负调控因子BRC1的转录水平，进而促进拟南芥的分枝。研究结果为阐明HY5调控分枝的生物学功能提供了一定的理论依据。

关键词: 拟南芥, 光信号转导因子HY5, 分枝